Optical sensor

Abstract

The invention provides an optical sensor capable of reducing stray light. An optical sensor (100) is provided with: a light projection unit (11) that includes a light source (12) that emits light, and a light projection lens (16) that is configured so as to condense the light from the light source (12); a light receiving unit (21) that receives light; and a detection unit (40) that detects an object (TA) on the basis of the received light, the light projection unit (11) further comprising: a package (13) in which the light source (12) is provided on the bottom surface (13b) of a recess (13a) formed in the package (13); and a resin (14) which has translucency and covers the light source (12), in which a side surface (13c) of the recess (13a) contains a material that absorbs light from the light source (12).

Description

Technical Field

[0001] This invention relates to optical sensors. Background Technology

[0002] As optical sensors, there are typically two types: those that detect the type of an object based on the amount of light received, and those that detect the type of an object by converting the light distribution into the object's position. A specific example of the latter type is known as follows: A light distribution is obtained; if multiple maxima are detected in the light distribution, it is determined that multiple reflections have occurred, thus indicating the presence of an object. Conversely, even if no maxima are detected, the presence of an object is still determined based on a change in state. Furthermore, even if there is only one maxima, if the peak position exceeds a threshold range, the presence of an object is also determined. Additionally, if the width of the light waveform exceeds a specified range, the presence of an object is also determined (see Patent Document 1). This optical sensor detects the presence or absence of multiple reflections based on the light distribution and outputs a signal related to the presence or absence of multiple reflections, thereby enabling control corresponding to the occurrence of multiple reflections.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-221491

[0006] Previously, the light-emitting part of optical sensors used readily available packages that included both a light source and a package.

[0007] However, if such a package is used directly, the light from the light source is reflected by the package, generating unwanted light, i.e., stray light. In order to prevent this stray light from affecting the performance of optical sensors, countermeasures such as reducing the light emission of the light source have been implemented in the past. As a result, the conventional countermeasures have led to a decrease in the signal-to-noise ratio (hereinafter also referred to as "S / N ratio"). Summary of the Invention

[0008] The present invention was made in view of the following circumstances, and one of its objectives is to provide an optical sensor capable of reducing stray light.

[0009] An optical sensor according to one aspect of this disclosure includes: a light-emitting section comprising a light source emitting light and a light-concentrating element configured to concentrate the light from the light source; a light-receiving section receiving light; and a detection section detecting an object based on the received light. The light-emitting section further includes: an encapsulation having a light source disposed on the bottom surface of a recess formed in the encapsulation; and a resin having light transmittance and covering the light source, wherein the side surface of the recess contains a material that absorbs the light from the light source.

[0010] According to this method, the projection section further includes: an encapsulation, in which a light source is disposed on the bottom surface of a recess formed in the encapsulation; and a resin that is translucent and covers the light source, wherein the side surface of the recess contains a material that absorbs light from the light source. Thus, light incident from the light source disposed on the bottom surface onto the side surface is absorbed, thereby absorbing stray light that may be generated, stray light that includes the side surface and is a major factor in the generation path. Therefore, stray light can be reduced, and the decrease in the signal-to-noise ratio can be suppressed. Furthermore, the visual confirmability of the spot of the main light illuminating the object or the like can be improved.

[0011] In the aforementioned method, the side surface can also be connected to the bottom surface, and the angle between the side surface and the bottom surface is greater than 90 degrees.

[0012] According to this method, the side surface is connected to the bottom surface, and the angle between them is greater than 90 degrees. This increases the opening of the recess, allowing more light from a light source located on the bottom surface to escape from the package.

[0013] In the aforementioned method, the reflectivity of the light from the side to the light source can also be less than 10%.

[0014] According to this method, the reflectivity of light from the side to the light source is less than 10%. Therefore, stray light originating from the side can be effectively absorbed, reducing the possibility of false detection of objects.

[0015] In the aforementioned method, the side surface can also be rough.

[0016] According to this method, the side surface is rough. As a result, light undergoes diffuse reflection on its surface, thus reducing the reflectivity of the side surface.

[0017] In the aforementioned method, the encapsulation can also be formed from a material that absorbs light from a light source.

[0018] According to this method, the package is formed from a material that absorbs light from a light source. This stabilizes the stray light suppression properties and allows for easy manufacturing of the package.

[0019] In the aforementioned method, the encapsulation can also be formed from a material that absorbs light from a light source, with a metal electrode pattern on the surface of the bottom surface, and the light source is connected to the metal electrode pattern.

[0020] According to this method, the package is formed from a material that absorbs light from a light source, and has a metal electrode pattern on the bottom surface. The light source is connected to the metal electrode pattern. Therefore, if the LED lead frame is used as the light source, various reflections will occur, thus causing stray light problems. However, by forming electrodes on the bottom surface as a wiring pattern made of metal, even if light from the light source shines on the electrodes, the pattern surface is mirror-like and the incident angle is large, thus suppressing the generation of diffuse reflection light and reducing stray light generation.

[0021] In the aforementioned method, the light-projecting part and the light-receiving part can also be separate frames, with the light-projecting part irradiating a light beam to the outside, and the light-receiving part being set to receive the light emitted from the light-projecting part, and the detection part detecting the object based on the change in the amount of light received.

[0022] According to this method, the light-projecting part and the light-receiving part are separate frames. The light-projecting part illuminates the outside with a light beam, and the light-receiving part is configured to receive the light emitted from the light-projecting part. The detection part detects the object based on the change in the amount of light received. As a result, false detection of the object caused by stray light being received by the object itself or by stray light being reflected and received by an object other than the object, such as a device, can be suppressed.

[0023] In the aforementioned method, the projection section and the receiving section may be housed in a common frame, with the projection section irradiating the light beam toward the retroreflector, the receiving section configured to receive the light reflected by the retroreflector, and the detection section detecting the object based on the change in the amount of light received.

[0024] According to this method, the light-projecting part and the light-receiving part are arranged in a common frame. The light-projecting part irradiates a light beam toward the retroreflector, and the light-receiving part is configured to receive the light reflected by the retroreflector. The detection part detects the object based on the change in the amount of light received. As a result, false detection of objects caused by stray light being reflected and received by the object, the reduction in the degree of freedom of setting, and the reduction in the detection performance of transparent objects can be suppressed.

[0025] In the aforementioned method, the projection section and the receiving section may be housed in a shared frame. The projection section illuminates the light beam outward, and the receiving section has a light-receiving field of view and is configured to receive reflected light from the area where the light beam intersects with the light-receiving field of view. The detection section detects the object based on the change in the amount of light received.

[0026] According to this method, the light-projecting part and the light-receiving part are disposed in a shared frame. The light-projecting part illuminates the light beam outward, and the light-receiving part has a light-receiving field of view and is configured to receive reflected light from the area where the light beam intersects with the light-receiving field of view. The detection part detects the object based on the change in the amount of light received. Therefore, it is possible to suppress the expansion of the detection range caused by stray light, maintain the detection range, and suppress false detections caused by stray light being reflected and received by objects other than the object, such as equipment.

[0027] In the aforementioned manner, the light-receiving axis of the light-receiving part and the light-projecting axis of the light-projecting part can be configured to intersect in a manner that limits the area in which the light beam intersects with the field of view of the light-receiving part.

[0028] According to this method, the light-receiving axis of the light-receiving part and the light-projecting axis of the light-projecting part are intersected in a manner that limits the area where the light beam intersects with the field of view. This solves the problem of difficulty in achieving area limitation when stray light is present.

[0029] In the aforementioned method, the light-projecting part can also irradiate a light beam to the outside, and the light-receiving part can be configured such that multiple pixels can each detect the amount of light received, and can obtain the light amount distribution signal of each pixel for the received light, and the detection part can detect the object based on the light amount distribution signal.

[0030] According to this method, the light-projecting part illuminates a light beam to the outside, and the light-receiving part is configured such that multiple pixels can each detect the amount of light received, and is configured to acquire a light-receiving amount distribution signal for each pixel in response to the received light. The detection part detects an object based on the light-receiving amount distribution signal. As a result, stray light components in the light-receiving amount distribution signal can be suppressed, the center of gravity of the light-receiving amount signal can be reduced, and false detection of objects can be suppressed.

[0031] According to the present invention, stray light can be reduced. Attached Figure Description

[0032] Figure 1 This is a block diagram illustrating the schematic structure of the optical sensor in the first embodiment.

[0033] Figure 2 This is a diagram used to illustrate the detection principle of the optical sensor in the first embodiment.

[0034] Figure 3 This is a cross-sectional view illustrating the general structure of the periphery of the light-emitting section of the optical sensor in the first embodiment.

[0035] Figure 4 This is an enlarged cross-sectional view of the main part of the schematic structure of the light-projecting part of the optical sensor in the first embodiment.

[0036] Figure 5This is a diagram used to illustrate the stray light path in a hypothetical projection section.

[0037] Figure 6 This is an image illustrating a spot of light when light emitted from the projection section of the optical sensor in the first embodiment illuminates an object.

[0038] Figure 7 This is a diagram illustrating an example of the effect of stray light in conventional optical sensors.

[0039] Figure 8 This is another example illustrating the effect of stray light in conventional optical sensors.

[0040] Figure 9 This diagram illustrates the detection principle of the optical sensor in the second embodiment when there is no object present.

[0041] Figure 10 This diagram illustrates the detection principle of the optical sensor in the second embodiment when an object is present.

[0042] Figure 11 This diagram illustrates the detection principle of the optical sensor in the second embodiment when other objects are present.

[0043] Figure 12 This diagram illustrates the effect of stray light when detecting an object in a conventional optical sensor.

[0044] Figure 13 This diagram illustrates the effect of stray light when detecting an object in a conventional optical sensor.

[0045] Figure 14 This diagram illustrates the effect of stray light when detecting other objects in conventional optical sensors.

[0046] Figure 15 This is a diagram illustrating the detection principle of the optical sensor in the third embodiment.

[0047] Figure 16 This diagram illustrates the effect of stray light in conventional optical sensors.

[0048] Figure 17 This diagram illustrates the effect of stray light in conventional optical sensors.

[0049] Figure 18 This is a diagram illustrating the detection principle of the optical sensor in the fourth embodiment.

[0050] Figure 19 This is a diagram used to illustrate the effect of stray light in conventional optical sensors.

[0051] Figure 20 This is a block diagram illustrating the schematic structure of the optical sensor in the fifth embodiment.

[0052] Figure 21 This is a diagram illustrating the detection principle of the optical sensor in the fifth embodiment.

[0053] Figure 22 This is a schematic diagram illustrating an application example of the optical sensor in the fifth embodiment.

[0054] Figure 23 This is a waveform diagram illustrating an example of a light distribution signal.

[0055] Figure 24 This is a waveform diagram used to illustrate the effect of stray light in conventional optical sensors.

[0056] Label Explanation

[0057] 10 Projector; 11 Projection section; 12 Light source; 13 Encapsulation; 13a Recess; 13b Bottom surface; 13c Side surface; 13d Opening; 14 Resin; 15 Bonding line; 16 Projection lens; 19 Projection drive circuit; 20 Receiver; 21, 21A Light receiving section; 22 Shielding; 26 Light receiving lens; 29 Signal processing circuit; 40, 40A Detection section; 41 Judgment section; 42 Calculation section; 50, 50A, 50B Control section; 60, 60A... 60B Input / Output I / F; 70, 70A, 70B Storage Units; 80, 80A, 80B Input / Output Control Units; 81, 81A, 81B Operation Units; 82, 82A, 82B Output Units; 100, 200, 300, 400, 500 Optical Sensors; 210, 310, 410 Light Projectors / Receivers; 530 Main Body; BG Background; EQ Equipment; RP Retroreflector; TA, TA1, TA2 Objects; θ Angle. Detailed Implementation

[0058] The following describes embodiments of the present invention. In the following drawings, the same or similar parts are indicated by the same or similar reference numerals. However, the drawings are schematic. Therefore, specific dimensions, etc., should be determined in conjunction with the following description. Furthermore, the drawings also include portions with different dimensional relationships and ratios. Moreover, the scope of the present invention should not be construed as limited to this embodiment.

[0059] [First Implementation Method]

[0060] First, refer to Figure 1 The structure of the optical sensor according to the first embodiment will be described. Figure 1This is a block diagram illustrating the schematic structure of the optical sensor 100 in the first embodiment.

[0061] like Figure 1 As shown, the optical sensor 100 includes a light emitter 10 and a light receiver 20. The optical sensor 100 is, for example, a photoelectric sensor, configured to detect an object TA by utilizing various properties of light.

[0062] The optical sensor 100 in this embodiment is a transmission-type photoelectric sensor, with the projector 10 and the receiver 20 respectively housed in their respective frames (casings).

[0063] The projector 10 includes a control unit 50A, an input / output (I / F) interface 60A, a storage unit 70A, an input / output control unit 80A, an operation unit 81A, and an output unit 82A. The receiver 20 includes a detection unit 40, a control unit 50B, an input / output (I / F) interface 60B, a storage unit 70B, an input / output control unit 80B, an operation unit 81B, and an output unit 82B.

[0064] The detection unit 40 is configured to detect an object TA based on light received by the light-receiving unit 21 (described later). The detection unit 40 includes a processor. In this case, a program and data for detecting the object TA are programmed into the processor of the detection unit 40. Specifically, the detection unit 40 is configured to control the light emitter 10. The detection unit 40 generates control signals, for example, by controlling the intensity (power) of the light projected by the light emitter 10, the duration of light projection, the period or interval of light projection, and the timing of light projection. The generated control signals are output to the signal processing circuit 29.

[0065] The detection unit 40 includes a determination unit 41 as a functional block. A light-receiving amount signal, representing the amount of light received by the light-receiving unit 21 (hereinafter also referred to as "light-receiving amount"), is input to the detection unit 40 via the signal processing circuit 29. The detection unit 40 is configured to detect the object TA based on changes in this light-receiving amount. In one example, the detection unit 40 outputs the detection signal and light-receiving amount (described later) to the outside via the input / output I / F 60. Further details regarding the determination unit 41 will be described later.

[0066] Control unit 50A is configured to control the operation of each part of the projector 10, and control unit 50B is configured to control the operation of each part of the receiver 20. For example, control unit 50B is connected to detection unit 40 and exchanges signals and data with detection unit 40. Control unit 50A is configured to include a processor such as a CPU (Central Processing Unit). Furthermore, control unit 50B is configured to include a processor such as an ASIC (Application Specific Integrated Circuit).

[0067] Input / output I / F 60A is the interface between the projector 10 and external devices, and input / output I / F 60B is the interface between the receiver 20 and external devices. Input / output I / F 60A and 60B are configured to exchange data and signals with external devices. Furthermore, input / output I / F 60A and 60B are configured to control communication with external devices.

[0068] Storage units 70A and 70B are configured to store programs, data, etc. Specifically, storage unit 70A stores data such as programs executed by control unit 50A, setting items and setting content, and set values, while storage unit 70B stores data such as programs executed by control unit 50B, setting items and setting content, and set values. Storage units 70A and 70B may be configured to include, for example, ROM (Read Only Memory), RAM (Random Access Memory), flash memory, or other similar memory.

[0069] Input / output control unit 80A is configured to control the operation of output unit 82A, and input / output control unit 80B is configured to control the operation of output unit 82B. Input / output control unit 80A is connected to operation unit 81A and output unit 82A, and input / output control unit 80B is connected to operation unit 81B and output unit 82B. Furthermore, input / output control unit 80A is connected to control unit 50A and exchanges data with control unit 50A, and input / output control unit 80B is connected to control unit 50B and exchanges data with control unit 50B. Input / output control unit 80A may be configured to include a processor such as a CPU.

[0070] exist Figure 1 The example shown illustrates a structure where the control unit 50A and the input / output control unit 80A are separate elements, but this is not a limitation. For example, the control unit 50A and the input / output control unit 80A may also be integrated. In this case, the control unit 50A and the input / output control unit 80A may be configured to include a processor such as a CPU. Similarly, the example shows a structure where the detection unit 40, the control unit 50B, and the input / output control unit 80B are separate elements, but this is not a limitation. For example, at least two of the detection unit 40, the control unit 50B, and the input / output control unit 80A may be integrated. When the detection unit 40, the control unit 50B, and the input / output control unit 80A are integrated, for example, they may be configured to include a processor such as an ASIC.

[0071] Operation unit 81A is used to input information to the projector 10, and operation unit 81B is used to input information to the receiver 20. Operation units 81A and 81B may be configured to include, for example, buttons, switches, touch panels, or keyboards. For example, when a user operates at least one of the buttons, switches, touch panels, or keyboards, input / output control units 80A and 80B generate data corresponding to that operation. In this way, information is input to the projector 10 and the receiver 20.

[0072] Output units 82A and 82B are used to output information. Output units 82A and 82B may, for example, include a display device, an indicator light, and a speaker. The indicator light may, for example, include a single-lamp indicator light based on a conventional light-emitting diode (LED), or a seven-segment LED. In this case, a surface-emitting LED is used as the light-emitting element. The display device may, for example, include a display panel such as a liquid crystal display, an EL (Electro-Luminescence) display, a plasma display, an organic EL (OLED) display, a quantum dot organic EL (QD-OLED) display, a mini-LED display, or a micro-LED display. Output unit 82 drives at least one of the display device, the indicator light, and the speaker to output information based on a control signal input from the input / output control unit 80.

[0073] In this embodiment, an example of using an ASIC or CPU as a processor is shown, but it is not limited to this. The processor of the optical sensor 100 can replace the ASIC or CPU, or be used in conjunction with the ASIC or CPU with an integrated circuit such as a DSP (Digital Signal Processor), FPGA (Field-Programmable Gate Array), PLD (Programmable Logic Device), or SoC (System-on-a-Chip).

[0074] The projector 10 also includes a light-emitting section 11 and a light-emitting drive circuit 19. The light-emitting section 11 is configured to emit light, for example, from a light-emitting window (not shown) formed in the frame. The light-emitting drive circuit 19 drives the light-emitting section 11. Specifically, the light-emitting drive circuit 19 outputs a drive signal to the light-emitting section 11 based on a control signal input from the control unit 50A. The light-emitting section 11 is driven by the drive signal and emits light.

[0075] The light receiver 20 also includes a light-receiving section 21 and a signal processing circuit 29. The light-receiving section 21 is configured to receive, for example, light incident from a light-receiving window (not shown) formed in the frame. More specifically, the light-receiving section 21 is configured to receive light emitted from the light-emitting section 11. The light-receiving section 21 may include, for example, one or more light-receiving elements. The light-receiving element is, for example, a photodiode (PD). In addition to the light-receiving element, the light-receiving section 21 may also include a condenser lens, a filter, etc. The light-receiving element outputs an electrical signal corresponding to the amount of light received during a predetermined exposure time. Furthermore, when using a PD as the light-receiving element, a charge accumulation section that accumulates charge corresponding to the amount of light received during the exposure time may be externally provided.

[0076] The signal processing circuit 29 controls the light-receiving unit 21. For example, the signal processing circuit 29 outputs a control signal to the light-receiving unit 21 in such a way that the light-receiving element receives light during the exposure time and outputs an electrical signal during periods other than the exposure time, i.e., non-exposure periods. This control signal is input from the detection unit 40.

[0077] Furthermore, the signal processing circuit 29 receives an electrical signal from the light-receiving element of the light-receiving unit 21. The signal processing circuit 29 includes an amplifier circuit (not shown) that amplifies the input electrical signal with a predetermined gain and outputs it. Alternatively, if the electrical signal from the light-receiving unit 21 is a current signal, the signal processing circuit 29 may also include a current-to-voltage conversion circuit. In this case, the signal processing circuit 29 converts the input current signal into a voltage value corresponding to the current value. Then, the signal processing circuit 29 amplifies the converted voltage signal using the amplifier circuit and outputs it. This amplified signal is output to the detection unit 40 as a signal representing the amount of light received.

[0078] Here, the detection principle of the optical sensor in the first embodiment will be explained. Figure 2 This is a diagram illustrating the detection principle of the optical sensor 100 in the first embodiment.

[0079] like Figure 2 As shown, the projector 10 and the receiver 20 are respectively configured such that light emitted from the projector 10 is incident on the receiver 20. More specifically, the projector 10 and the receiver 20 are arranged such that the projection window of the projector 10 and the receiving window of the receiver 20 are opposite each other. If an object TA exists in the space between the projector 10 and the receiver 20, the object TA will block or attenuate the light emitted from the projector 10, reducing the amount of light incident on the receiver 20. Figure 1 The detection unit 40 shown is configured to detect the object TA based on the change in the amount of light received by the light receiving unit 21 of the light receiver 20, and generate a detection signal for the object TA.

[0080] Specifically, Figure 1 The determination unit 41 of the detection unit 40 compares the amount of light received by the light receiver 20 with a threshold value for determination to determine the presence or absence of the object TA. When the amount of light received is above the threshold, it is assumed that the object TA does not exist between the projector 10 and the light receiver 20. Therefore, the detection unit 40 sets the signal level of the detection signal to a level indicating an off state, such as a low level. On the other hand, when the amount of light received is below the threshold, it is assumed that the object TA exists between the projector 10 and the light receiver 20, and the light from the projector 10 to the light receiver 20 is blocked or attenuated by the object TA. Therefore, the detection unit 40 sets the signal level of the detection signal to a level indicating an on state, such as a high level. In this way, the detection unit 40 can detect the presence or absence of the object TA.

[0081] Next, refer to Figure 3 and Figure 4 The structure of the light-projecting part of the optical sensor in the first embodiment will be described. Figure 3 This is a cross-sectional view illustrating the schematic structure of the periphery of the light-emitting section 11 of the optical sensor 100 in the first embodiment. Figure 4 This is an enlarged cross-sectional view of the main parts of the schematic structure of the package 13 of the optical sensor 100 in the first embodiment.

[0082] The projection section 11 is housed inside the frame of the projector 10. The projection section 11 projects a beam of light outwards. Figure 3 As shown, in addition to the light-emitting part 11, the frame of the projector 10 also includes a lens bracket 17 and a substrate 18.

[0083] The light-emitting unit 11 includes a light source 12, a package 13, and a light-emitting lens 16. The light source 12 is configured to emit light. The light source 12 may include, for example, a light-emitting element such as an LED or a laser diode.

[0084] Furthermore, regardless of the type of light emitted, light source 12 can utilize a variety of light sources. For example, light source 12 can be a point light source or a surface-emitting LED. It can also be a laser diode that emits a vertical-cavity surface-emitting laser (VCSEL).

[0085] Package 13 is on one side ( Figure 3 and Figure 4 The upper surface of the package 13 has a recess 13a, such as a cavity or depression. The material of the package 13 is, for example, a ceramic such as epoxy resin, alumina (Al2O3), or aluminum nitride (AlN). The package 13 is formed together with the recess 13a, for example, using a mold.

[0086] like Figure 4 As shown, the recess 13a includes a light projection direction toward the light in the projector 10, for example... Figure 3 and Figure 4 An opening 13d opens in the positive Y-axis direction. Furthermore, the recess 13a also includes a bottom surface 13b for mounting the light source 12. The light source 12 is configured such that the emitting surface (hereinafter also referred to as "main light") emits the primary light. Figure 3 and Figure 4 The upper surface of the middle surface faces the opening 13d side.

[0087] The projection section 11 also includes resin 14 covering the light source 12. The resin 14 is transparent to the light from the light source 12. The material of the resin 14 is, for example, epoxy resin or silicone resin. The resin 14 fills the recess 13a after the light source 12 is disposed on the bottom surface 13b.

[0088] Thus, the projection section 11 also includes a resin 14 that is translucent and covers the light source 12. As a result, the light source 12 can be protected, and the light source 12 can be fixed to the bottom surface 13b of the recess 13a.

[0089] The recess 13a also includes a side surface 13c connecting the bottom surface 13b and the opening 13d. The side surface 13c and the bottom surface 13b have an angle θ between them. The recess 13a is formed such that the area of ​​the bottom surface 13b is smaller than the area of ​​the surface containing the opening 13d (hereinafter also referred to as the "opening surface"). Therefore, the side surface 13c is inclined at an angle θ greater than 90 degrees and less than 180 degrees (180° > θ > 90°). This increases the opening surface of the recess 13a, allowing more light emitted from the light source 12 disposed on the bottom surface 13b to escape from the package 13.

[0090] The projection section 11 also includes a bonding wire 15 connected to the light source 12. The bonding wire 15 is, for example, a wiring made of gold (Au) that electrically connects the light source 12 to the substrate 18.

[0091] The projection lens 16 is configured to focus the light from the light source 12. Specifically, the projection lens 16 is positioned at a predetermined distance from the package 13. More specifically, the projection lens 16 is positioned on one side relative to the package 13 so that light emitted from the opening 13d of the recess 13a is incident on the projection lens 16. Figure 3 (On the positive Y-axis side). The projection lens 16 is fixed and held by the lens holder 17.

[0092] The projection lens 16 is, for example, a convex lens. In this case, the projection lens 16 directs the light incident onto a surface ( Figure 3 The light beam is refracted from the lower surface of the beam and converged to a predetermined focal point from another surface (the lower surface of the beam). Figure 3 (From the upper surface of the middle)

[0093] Thus, the optical sensor 100 also includes a projection lens 16 disposed relative to the package 13 so that light emitted from the opening 13d of the recess 13a can be incident on it. As a result, by refracting, diverging or converging the light emitted from the package 13, light can be easily irradiated onto the object TA or the light-receiving part 21.

[0094] In this embodiment, an example of one projection lens 16 is shown, but it is not limited to this. The optical sensor 100 may also have two or more projection lenses. Furthermore, the optical sensor 100 may replace the projection lens or have other lenses together with the projection lens, and may also have other optical components, such as reflectors.

[0095] Here, the generation of stray light will be explained. Figure 5 This diagram illustrates the stray light path in a hypothetical projection section. Furthermore, the hypothetical projection section is a projection section found in conventional optical sensors; structures identical or similar to the projection section 11 of this embodiment are labeled with the same or similar reference numerals, and their descriptions are appropriately omitted. Figure 5 Is with Figure 4 The figure shows an enlarged cross-sectional view of the main part of the package 13.

[0096] like Figure 5 As shown, the light source 12 is disposed on the bottom surface of the recess (not shown) formed in the package 13' and is covered by resin 14. Furthermore, a bonding line 15 is connected to the light source 12.

[0097] Stray light generated in a hypothetical projection area can be exemplified by the following: Figure 5 As shown by the dashed line, light emitted from the side of the light source 12 is reflected from the side of the recess formed in the package 13', producing stray light along the path incident on the projection lens (not shown). Furthermore, as... Figure 5 As shown by the dashed line, light emitted from the upper surface of the light source 12 is reflected on the surface of the resin 14, and then reflected on the bottom surface of the recess formed in the package 13', generating stray light along the path incident on the projection lens. Furthermore, as... Figure 5 As shown by the double-dotted line, light emitted from the upper surface of the light source 12 is reflected by the bonding line 15, and then reflected on the bottom surface of the recess formed in the package 13' to generate stray light along the path incident on the projection lens.

[0098] The inventors of this application used optical simulation to analyze stray light in a hypothetical projection section, and found that: stray light traveling along various generation paths... Figure 5The stray light in the generation path shown by the dashed line is the main factor. Therefore, it was considered that by implementing measures to reduce the amount of this stray light, the impact of stray light could be significantly suppressed.

[0099] In contrast, formed in Figure 4 The side surface 13c of the recess 13a of the package 13 shown in this embodiment contains a material that absorbs light emitted by the light source 12. Specifically, the side surface 13c is made of a black material. For example, the side surface 13c is made of black epoxy resin. Alternatively, the side surface 13c is formed by sintering a black pigment mixed in powder such as alumina. In all the side surfaces 13c surrounding the light source 12, it is preferable to include a material that absorbs light from the light source 12. Furthermore, not only the side surfaces 13c, but the entire package 13 can also be formed of a material that absorbs light from the light source 12.

[0100] Here, for comparison, Figure 5 The light intensity and reflectivity of the hypothetical light-projecting section are explained. In the hypothetical light-projecting section, when using a white package 13' with relatively high reflectivity, the amount of stray light illuminating an object, such as a screen, is 153% of the amount of main light, and the stray light is more than 1.5 times that of the main light. At this time, the reflectivity of the package 13' for the wavelength range of 610nm to 980nm of the light source 12 is approximately 90%.

[0101] The reflectivity (= numerator / denominator) here is defined as follows.

[0102] • Denominator: The total amount of light emitted from the light source 12 that is directly incident on the side 13c of the package 13 is used as the denominator. Here, light reflected by other paths and incident on the side 13c is not included.

[0103] • Molecules: The total amount of light incident on the aforementioned side 13c that is reflected near the interface of side 13c and passes directly through the opening 13d is defined as molecules. Here, light passing through the opening 13d via other paths is not included.

[0104] In contrast, Figure 4 In the package 13 of this embodiment shown, when the entire package 13, including the side 13c, is black, the amount of stray light from the illumination light illuminating an object, such as a screen, is 0.03% of the amount of the main light, which is practically negligible. At this time, the reflectivity of the package 13 to the wavelength of the light source 12 in the 610nm to 980nm range is approximately 4%.

[0105] Next, refer to Figure 6 The illumination light of the light-projecting part of the optical sensor in the first embodiment will be described. Figure 6This is an image illustrating the light spot when light emitted from the light-projecting section 11 of the optical sensor 100 in the first embodiment illuminates an object. Additionally, Figure 6 The image shown was obtained by placing graph paper at a predetermined distance from the projector 10 and taking a picture of the light shining on the paper.

[0106] like Figure 6 As shown, when using a surface-emitting LED as the light source 12, it can be confirmed that in the illumination light IL1 on the graph paper 100 mm from the projector 10, stray light is significantly reduced, and the proportion of the main light is high. Similarly, it can be confirmed that in the illumination light IL2 on the graph paper 200 mm from the projector 10, stray light is also significantly reduced, and the proportion of the main light remains high. Furthermore, even when using a point-emitting LED as the light source 12, it can be confirmed that in the illumination light IL3, stray light is significantly reduced, and the proportion of the main light is high.

[0107] Thus, in the optical sensor 100, the light-emitting section 11 further includes: a package 13, with a light source 12 disposed on the bottom surface 13b of a recess 13a formed in the package 13; and a resin 14, which is light-transmitting and covers the light source 12, with the side surface 13c of the recess 13a containing a material that absorbs the light from the light source 12. Therefore, light incident from the light source 12 disposed on the bottom surface 13b onto the side surface 13c is absorbed, thereby absorbing stray light that may be generated, including stray light that includes the side surface 13c in its generation path and is a major factor. Therefore, stray light can be reduced, and the decrease in the S / N ratio can be suppressed. Furthermore, the visual confirmability of the spot of the main light illuminating the object TA, etc., can be improved.

[0108] The side surface 13c preferably has a reflectivity greater than 0% and less than 10% for light emitted from the light source 12. Generally, in practical applications, when black paper is assumed to be the object with the lowest reflectivity among objects detected by a photoelectric sensor, its reflectivity is 6%. On the other hand, when objects made of metals such as aluminum (Al) are assumed to be objects with relatively high reflectivity, their reflectivity is 60% or more. Furthermore, when using an LED as a light source, if the light emission from the front and the side is considered to be approximately equal, when the light from the front shines on the black paper at the center of the light spot and the light from the side is reflected by metal objects surrounding the light spot, it is necessary to avoid either false detection of the object due to ambient light or failure to detect the object due to ambient light (hereinafter, both will be collectively referred to as "false detection"). Therefore, the reflectivity of the side of the package into which light from the LED side is incident is preferably less than 10%.

[0109] Thus, the reflectivity of the light emitted by the light source 12 to the side 13c is less than 10%. As a result, stray light generated by the side 13c can be effectively absorbed, thereby reducing the possibility of false detection of the object TA.

[0110] Furthermore, more preferably, the reflectivity of the side surface 13c to light emitted from the light source 12 is greater than 0% and less than 6%. That is, even if approximately 100% of the light is reflected by a highly reflective object such as a reflective film present in the surrounding area, which is theoretically the highest value, false detection of objects due to ambient light is also considered. In this case, the reflectivity of the side surface of the package to which light from the LED side is incident is preferably less than 6%.

[0111] Thus, the reflectivity of the side 13c to the light emitted by the light source 12 is less than 6%. As a result, stray light generated by the side 13c can be absorbed more efficiently, thereby further reducing the possibility of false detection of the object TA.

[0112] Furthermore, the side surface 13c can also be a rough surface. In this case, the side surface 13c is formed using a mold with a rough surface. Specifically, the surface roughness of the side surface 13c, for example, the maximum value of the arithmetic mean roughness (Ra) is 0.03 μm or more. In this way, by making the side surface 13c a rough surface, light is diffusely reflected on its surface, and therefore, as a result, the reflectivity of the side surface 13c can be reduced.

[0113] The flatness of side surface 13c can be lower than that of opening 13d (the interface of resin 14). Opening 13d is typically manufactured flat. If opening 13d is a rough surface, scattering will occur there, which is not preferable.

[0114] Package 13 is formed from a material that absorbs light from light source 12. As a result, the property of suppressing stray light is stabilized, and package 13 can be easily manufactured.

[0115] Alternatively, the package 13 may have a metal electrode pattern on the surface of the bottom surface 13b, and the light source 12 may be connected to the metal electrode pattern. Therefore, if the LED lead frame is used as the light source 12, various reflections will occur, thus stray light becomes a problem. However, by forming electrodes on the bottom surface 13b as a wiring pattern made of metal, even if the light from the light source 12 shines on the electrodes, the generation of diffuse reflection light can be suppressed because the pattern surface is mirrored and the incident angle is large, thereby reducing the generation of stray light.

[0116] Next, refer to Figure 7 and Figure 8 This explains the effect of stray light in conventional optical sensors. Figure 7 This is a diagram illustrating an example of the effect of stray light in conventional optical sensors. Figure 8This is another example illustrating the effect of stray light in conventional optical sensors. Additionally, Figure 7 and Figure 8 The conventional optical sensors are transmission-type photoelectric sensors. For the sake of simplicity, only the light transmitter and light receiver of the conventional optical sensors are shown.

[0117] like Figure 7 As shown, when multiple optical sensors are arranged close together, if the light emitted from the projector 10' contains stray light (shown by the dashed line), this stray light may enter the photodetector 20" of an adjacent optical sensor. In this case, the light emitted from the projector 10" should normally be blocked by the object TA, thus detecting the object TA. However, because the stray light enters the photodetector 20" and is received, it may be mistakenly determined that there is no object TA.

[0118] And, as Figure 8 As shown, when a device EQ is present near an optical sensor, if the light emitted from the projector 10' contains stray light (shown by the dashed line), this stray light may be reflected by the device EQ and incident on the receiver 20'. In this case, the light emitted from the projector 10' should be blocked by the object TA located between the projector 10' and the receiver 20', and the object TA should be detected due to the reduced light intensity. However, the reflected light, reflected by the device EQ, is incident on the receiver 20' and received. As a result, it is possible that the light intensity does not decrease significantly, leading to a false determination that there is no object TA.

[0119] In contrast, in the optical sensor 100 of this embodiment, the light-emitting part 11 and the light-receiving part 21 are separate frames. The light-emitting part 11 illuminates a light beam to the outside, and the light-receiving part 21 is configured to receive light emitted from the light-emitting part 11. The detection unit 40 detects the object TA based on the change in the amount of light received. This suppresses false detections of the object TA caused by stray light being received by the object itself or by stray light being reflected and received by an object other than the object, such as a device EQ.

[0120] [Second Implementation]

[0121] Next, refer to Figures 9 to 11 The detection principle of the optical sensor in the second embodiment will be explained. Figure 9 This diagram illustrates the detection principle of the optical sensor 200 in the second embodiment when there is no object present. Figure 10 This is a diagram illustrating the detection principle of the optical sensor 200 in the second embodiment when an object TA1 is present. Figure 11This diagram illustrates the detection principle of the optical sensor 200 in the second embodiment when another object TA2 is present. Furthermore, in the second embodiment, structures that are the same as or similar to those in the first embodiment are labeled with the same or similar reference numerals, and their descriptions are appropriately omitted unless specifically stated otherwise. Moreover, the following description primarily focuses on the differences from the first embodiment, without repeatedly mentioning the same effects resulting from structures identical to those in the first embodiment.

[0122] The optical sensor 200 in this embodiment is a retroreflective photoelectric sensor. For example... Figure 9 As shown, the light-emitting part 11 and the light-receiving part 21 are housed in the same frame as a light-emitting and light-receiving unit 210. The light-emitting and light-receiving unit 210 is arranged opposite to the retroreflector RP. The retroreflector RP may be, for example, a resin molded product or a sheet structure. The light-emitting part 11 irradiates a light beam from the package 13, on which the light source 12 is provided on the bottom surface 13b, toward the retroreflector RP via the light-emitting lens 16. The irradiated light is reflected by the retroreflector RP and returns to the light-emitting and light-receiving unit 210. This reflected light is configured to be received by the light-receiving part 21 via the light-receiving lens 26.

[0123] like Figure 10 As shown, when the object TA1 is present in the space between the light emitter 210 and the retroreflector RP, the light beam emitted from the light emitter 11 is blocked by the object TA1. The light reflected by the object TA1 is configured not to incident on the light receiver 21. More specifically, a shielding object 22, such as a slit, is provided in the light receiver 21, and the light reflected at a position closer to the retroreflector RP is designed to incident on the shielding object 22. Therefore, the amount of reflected light received by the light receiver 21 is reduced. Similarly to the first embodiment, the detection unit 40 is configured to detect the object TA1 based on the change in the amount of reflected light received and generate a detection signal for the object TA1.

[0124] And, as Figure 11 As shown, when a transparent object TA2 exists in the space between the light emitter 210 and the retroreflector RP, a portion of the light beam emitted from the light emitter 11 passes through the object TA2 and is reflected by the retroreflector RP. The reflected light may then pass through the object TA2 again and enter the light receiver 21. At this time, a portion of the light incident on the surface of the object TA2 is refracted, and the refracted light does not enter the light receiver 21. Therefore, the amount of reflected light received in the light receiver 21 is reduced. Similar to the first embodiment, the detection unit 40 is configured to detect the object TA2 based on the change in the amount of reflected light received and generate a detection signal for the object TA2.

[0125] Next, refer to Figures 12 to 14 The influence of stray light in conventional optical sensors is explained. Figure 12This is a diagram used to illustrate the effect of stray light when detecting an object TA1 in a conventional optical sensor 200'. Figure 13 This is a diagram used to illustrate the effect of stray light when detecting an object TA1 in a conventional optical sensor 200'. Figure 14 This diagram illustrates the effect of stray light when detecting other objects TA2 in a conventional optical sensor 200'. Additionally, Figures 12 to 14 The conventional optical sensor 200' is a retroreflective photoelectric sensor. For the sake of simplicity, only the light transmitter and receiver 210' of the conventional optical sensor is shown.

[0126] like Figure 12 As shown, if the light emitted from the package 13' and the projection lens 16 in the projection section 11' contains stray light as indicated by the dashed line, then if the object TA1 is a piece of white paper or the like, the stray light will be diffusely reflected by the object TA1 and easily incident on the light receiving section 21' and be received. In this case, the light emitted from the projection section 11' should originally be reflected by the object TA1, and the reflected light should be blocked by the shielding object 22 to detect the object TA1. However, because the stray light is incident on the light receiving section 21' and received, it is possible to mistakenly determine that there is no object TA1.

[0127] And, as Figure 13 As shown, when multiple retroreflectors RP1 and RP2 are arranged adjacent to each other at a close distance, if the light emitted from the projection section 11' contains stray light (as indicated by the dashed line), this stray light may be reflected by the adjacent retroreflector RP2 and incident on the light-receiving section 21', where it will be received. In this case, the light emitted from the projection section 11' should ideally be reflected by the object TA1, and this reflected light should be blocked by the shielding object 22 to detect the object TA. However, since the reflected light reflected by the retroreflector RP2 is incident on the light-receiving section 21' and received, it is possible to mistakenly determine that there is no object TA. Therefore, the degree of freedom in setting up the conventional optical sensor 200' is reduced.

[0128] Furthermore, such as Figure 14As shown, when the object TA2 is transparent, if the light emitted from the projection section 11' contains stray light (as indicated by the dashed line), this stray light may be refracted by the object TA2 and reflected back to the retroreflector RP, and the reflected light may be refracted again by the object TA2 and incident on the light-receiving section 21'. In this case, the light emitted from the projection section 11' should be attenuated by the object TA2, and the object TA2 should be detected due to the reduced light intensity. However, the reflected light from the stray light refracted by the object TA2 is received by the light-receiving section 21'. As a result, the reduced light intensity may suppress the detection, or the light intensity may actually increase, leading to a false determination that the object TA2 is not present. Therefore, the detection performance of the transparent object TA2 in the conventional optical sensor 200' is reduced.

[0129] In contrast, in the optical sensor 200 of this embodiment, the light-emitting part 11 and the light-receiving part 21 are provided in a common frame. The light-emitting part 11 irradiates a light beam toward the retroreflector RP, and the light-receiving part 21 is configured to receive light reflected by the retroreflector RP. The detection part 40 detects objects TA1 and TA2 based on the change in the amount of light received. As a result, false detection of object TA1 caused by stray light being reflected and received by object TA1, the reduction in the degree of freedom of setting, and the reduction in the detection performance of transparent object TA2 can be suppressed.

[0130] [Third Implementation Method]

[0131] Next, refer to Figure 15 The detection principle of the optical sensor in the third embodiment will be explained. Figure 15 This diagram illustrates the detection principle of the optical sensor 300 in the third embodiment. Furthermore, the third embodiment uses the same or similar reference numerals for structures that are the same as or similar to those in the above embodiments, and descriptions of these structures are appropriately omitted unless explicitly stated otherwise. In the following description, the differences from the above embodiments will be primarily explained, without repeatedly mentioning the same effects of structures found in the above embodiments.

[0132] The optical sensor 300 in this embodiment is a diffuse reflection type photoelectric sensor. For example... Figure 15 As shown, the light-projecting part 11 and the light-receiving part 21 are housed in the same frame as a light-projecting receiver 310. The light-projecting part 11 illuminates a light beam to the outside. The light-receiving part 21 has a light-receiving field of view and is configured to receive reflected light from the area where the light beam intersects with the light-receiving field of view. When there is no object TA, the light beam emitted from the package 13, where the light source 12 is provided on the bottom surface 13b, via the light-projecting lens 16 in the light-projecting part 11 is not reflected and does not return to the light-projecting receiver 310. On the other hand, as Figure 15As shown, when an object TA is present in the portion where the spot of the light beam emitted from the projection unit 11 overlaps with the field of view of the light-receiving unit 21, the light is reflected by the object TA and returns to the projection-receiving unit 310. This reflected light is received by the light-receiving unit 21 via the light-receiving lens 26. Therefore, compared to when there is no object TA, the amount of reflected light received by the light-receiving unit 21 increases. The detection unit 40 is configured to detect the object TA based on the change in the amount of light received by the reflected light and generate a detection signal for the object TA.

[0133] Next, refer to Figure 16 and Figure 17 This explains the effect of stray light in conventional optical sensors. Figure 16 This is a diagram used to illustrate the effect of stray light in a conventional optical sensor 300'. Figure 17 This is a diagram used to illustrate the effect of stray light in a conventional optical sensor 300'. Additionally, Figure 16 and Figure 17 The conventional optical sensor 300' is a diffuse reflection type photoelectric sensor. For the sake of simplicity, only the light transmitter 310' of the conventional optical sensor 300' is shown.

[0134] like Figure 16 As shown, if the light emitted from the package 13' and the projection lens 16 in the projection section 11' contains stray light as indicated by the dashed line, the portion overlapping with the field of view, i.e., the detection range, expands. Therefore, the light emitted from the projection section 11', which was originally within the field of view, will illuminate objects such as objects TA located in positions not overlapping with the projection point. In applications where the light spot emitted from the projection section 11' is to be limited, although the detection range is the controlled object, stray light is not intended in the design; therefore, it is difficult to maintain a detection range containing stray light.

[0135] And, as Figure 17 As shown, in an environment where there are objects with high reflectivity, such as the device EQ, if the light emitted from the projection unit 11' contains stray light as indicated by the dashed line, this stray light may be reflected by the device EQ and incident on the light receiving unit 21', where it may be received. In this case, the object TA is not originally present, so the reflected light should not be received. However, since the reflected light reflected by the device EQ is incident on the light receiving unit 21' and received, it is possible to erroneously detect the presence of the object TA.

[0136] In contrast, in the optical sensor 300 of this embodiment, the light-emitting part 11 and the light-receiving part 21 are disposed in a common frame. The light-emitting part 11 illuminates a light beam to the outside, and the light-receiving part 21 has a light-receiving field of view and is configured to receive reflected light from the area where the light beam intersects with the light-receiving field of view. The detection part 40 detects the object TA based on the change in the amount of light received. As a result, the expansion of the detection range caused by stray light can be suppressed, the detection range can be maintained, and false detections caused by stray light being reflected and received by objects other than the object, such as the device EQ, can be suppressed.

[0137] [Fourth Implementation Method]

[0138] Next, refer to Figure 18 The detection principle of the optical sensor in the fourth embodiment. Figure 18 This diagram illustrates the detection principle of the optical sensor 400 in the fourth embodiment. Furthermore, the fourth embodiment uses the same or similar reference numerals for structures identical or similar to those in the above embodiments, and descriptions of these structures are omitted unless specifically stated otherwise. In the following description, the differences from the above embodiments will be primarily explained, without repeatedly mentioning the same effects of structures identical to those in the above embodiments.

[0139] The optical sensor 400 in this embodiment is a reflective photoelectric sensor. For example... Figure 18 As shown, the light-projecting part 11 and the light-receiving part 21 are housed in the same frame as a light-projecting receiver 410. The axis of the light emitted from the light-projecting part 11 of the light-projecting receiver 410 (hereinafter also referred to as the "projection axis") intersects the axis of the light incident on the light-receiving part 21 of the light-projecting receiver 410 (hereinafter also referred to as the "receiving axis"). More specifically, the light-receiving axis of the light-receiving part 21 and the projection axis of the light-projecting part 11 are configured to intersect in a manner that limits the area where the light beam intersects with the field of view. Figure 18 In this diagram, the projection axis of the projection section 11 is represented by a single-dotted line, and the light-receiving axis of the light-receiving section 21 is represented by a double-dotted line. Furthermore, the area overlapping the range of light emitted from the projection section 11 and the light-receiving area of ​​the light-receiving section 21 constitutes the detection area. Figure 18 In the example shown, the finite range of the rectangle enclosed by the light range indicated by the thick line and the light-receiving area indicated by the dashed line is the detection area DA. If an object TA is present in the detection area DA, the light beam emitted from the package 13, where the light source 12 is provided on the bottom surface 13b, via the projection lens 16 is reflected by the object TA and returns to the light receiver 410. This reflected light is received by the light-receiving unit 21 via the light-receiving lens 26. Therefore, compared to when there is no object TA in the detection area DA, the amount of reflected light received by the light-receiving unit 21 increases. The detection unit 40 is configured to detect the object TA based on the change in the amount of reflected light received and to generate a detection signal for the object TA.

[0140] Next, refer to Figure 19 This explains the effect of stray light in conventional optical sensors. Figure 19 This is a diagram used to illustrate the effect of stray light in a conventional optical sensor 400'. Additionally, Figure 19 The conventional optical sensor 400' is a limited reflective photoelectric sensor. For the sake of simplicity, only the light transmitter 410' of the conventional optical sensor 400' is shown.

[0141] like Figure 19 As shown, when the light emitted from the package 13' and the projection lens 16 in the projection section 11' contains stray light as indicated by the dashed line, the detection area expands. Figure 19 In the example shown, the detection area DA' extends to the area of ​​stray light indicated by the dashed line and the rectangular area surrounded by the illuminated area indicated by the dashed line. Therefore, the object TA, which would otherwise be outside the detection area, is included within the detection area DA'. Since stray light is not intended in the design, it is difficult to maintain the definition of the detection area.

[0142] In contrast, in the optical sensor 400 of this embodiment, the light-receiving axis of the light-receiving section 21 and the light-projecting axis of the light-projecting section 11 are configured to intersect in a manner that limits the area where the light beam intersects with the field of view. This solves the problem of difficulty in achieving area limitation when stray light is present.

[0143] [Fifth Implementation]

[0144] Next, refer to Figure 20 The structure of the optical sensor according to the fifth embodiment will be described. Figure 20 This is a block diagram illustrating the schematic structure of the optical sensor 500 in the fifth embodiment. Furthermore, in the fifth embodiment, structures that are the same as or similar to those in the above embodiments are labeled with the same or similar reference numerals, and their descriptions are appropriately omitted unless specifically stated otherwise. Moreover, the following description primarily focuses on the differences from the above embodiments, without repeatedly mentioning the same effects resulting from structures identical to those in the above embodiments.

[0145] The optical sensor 500 in this embodiment is a distance-setting type photoelectric sensor. For example... Figure 20 As shown, the optical sensor 500 includes a main body 530. The main body 530 includes a light-emitting unit 11, a light-emitting drive circuit 19, a light-receiving unit 21A, a signal processing circuit 29, a detection unit 40A, a control unit 50, an input / output I / F 60, a storage unit 70, an input / output control unit 80, an operation unit 81, and an output unit 82, all housed in the same frame.

[0146] The light-receiving unit 21A is configured such that multiple pixels receive light separately, and the amount of light received by each pixel can be detected. Furthermore, the light-receiving unit 21A is configured to acquire a light-receiving amount distribution signal representing the amount of light received by each pixel, as described later. The light-receiving unit 21A may include, for example, an imaging element. The imaging element may be, for example, a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor or a CCD (Charge-Coupled Device) image sensor. The imaging element includes multiple pixels, which are arranged one-dimensionally or two-dimensionally. Each pixel accumulates a charge corresponding to the amount of light received during a predetermined exposure time. Furthermore, each pixel outputs an electrical signal corresponding to the accumulated charge.

[0147] The detection unit 40A includes a determination unit 41 and a calculation unit 42 as functional blocks. The light intensity distribution signal obtained by the light receiving unit 21A is input to the detection unit 40A via the signal processing circuit 29. The detection unit 40A is configured to detect the object TA based on the change in the light intensity distribution signal. Further details regarding the determination unit 41 and the calculation unit 42 will be described later.

[0148] exist Figure 20 The example shown illustrates the structure of the determination unit 41 and the calculation unit 42 as functional blocks of the detection unit 40A, but it is not limited to this. For example, the determination unit 41 and the calculation unit 42 may also be configured as separate independent elements. Furthermore, the light-emitting drive circuit 19, the light-receiving unit 21A, the signal processing circuit 29, the determination unit 41, the calculation unit 42, the control unit 50, and the input / output control unit 80 are not limited to being separate independent elements. For example, at least two of the light-emitting drive circuit 19, the light-receiving unit 21A, the signal processing circuit 29, the determination unit 41, the calculation unit 42, the control unit 50, and the input / output control unit 80 may be configured as a single unit. More specifically, the light-receiving unit 21A, the signal processing circuit 29, and the determination unit 41 may be configured as a single unit including a processor such as an ASIC, and the light-emitting drive circuit 19, the calculation unit 42, the control unit 50, and the input / output control unit 80 may be configured as a single unit including a processor such as an ASIC. Alternatively, the light-emitting drive circuit 19, the light-receiving unit 21A, the signal processing circuit 29, and the computing unit 42 may be integrated into a processor such as an ASIC, and the determination unit 41, the control unit 50, and the input / output control unit 80 may be integrated into a processor such as an ASIC.

[0149] In addition, the optical sensor 200, optical sensor 300 and optical sensor 400 described above can also be configured in the same way as the optical sensor 500 of this embodiment.

[0150] Here, refer to Figure 21 The principle of the optical sensor in the fifth embodiment for detecting objects will be explained. Figure 21 This is a diagram illustrating the detection principle of the optical sensor 500 in the fifth embodiment.

[0151] like Figure 21 As shown, the main body 530 of the optical sensor 500 is positioned at a predetermined distance D1 from the object TA. In the projection section 11, a light beam emitted from the package 13, on which the light source 12 is provided on the bottom surface 13b, via the projection lens 16 is reflected by the object TA. The reflected light is incident on a portion of the pixels of the light-receiving section 21A via the light-receiving lens 26. On the other hand, a background BG is positioned, for example, at a distance D2 (distance D2 > distance D1) from the main body 530. The light reflected by the background BG is incident on the other pixels of the light-receiving section 21A via the light-receiving lens 26. Thus, in Figure 21 In the example shown, each pixel of the light-receiving portion 21A, which is arranged one-dimensionally in the vertical direction, corresponds to a distance D from the main body 530. Furthermore, in Figure 21 In the example shown, each pixel of the light-receiving part 21A can also be arranged in two dimensions in the vertical direction and the depth direction (the direction perpendicular to the paper). Therefore, by arranging each pixel of the light-receiving part 21A in one dimension or two dimensions, a light-receiving amount distribution signal representing the amount of light received by each pixel can be obtained, that is, a light-receiving amount distribution signal representing the amount of light received corresponding to the distance D from the main body 530.

[0152] Next, refer to Figure 22 An application example of the optical sensor according to the fifth embodiment will be described. Figure 22 This is a schematic diagram illustrating an application example of the optical sensor 500 according to the fifth embodiment.

[0153] like Figure 22 As shown, the main body 530 of the optical sensor 500 is positioned above the background BG and is configured to project light toward the background BG and receive reflected light. The object TA is placed on the background BG, and the background BG on which the object TA is placed projects light toward the background BG. Figure 22 Move in the direction indicated by the black arrow.

[0154] Here, refer to Figure 23 This section explains the distance based on the light distribution signal. Figure 23 This is a waveform diagram illustrating an example of a light distribution signal. In Figure 23 In the diagram, the horizontal axis represents each pixel of the light-receiving part 21A, and the vertical axis represents the amount of light received.

[0155] like Figure 23As shown, typically, the light distribution signal has a waveform where the light received by a certain pixel is the peak. The pixel with the peak light received in the light distribution signal obtained from the light receiving unit 21A is the pixel into which light is incident from the body 530 and reflected by the object TA. Moreover, the pixel corresponds to the distance from the body 530 to the object TA.

[0156] Specifically, the calculation unit 42 of the detection unit 40A calculates the coordinates of the centroid in the light distribution signal. Then, the calculation unit 42 converts the calculated coordinates into a distance. In this way, the calculation unit 42 can calculate the distance from the main body 530 to the object TA.

[0157] The determination unit 41 of the detection unit 40A determines whether the distance calculated by the calculation unit 42 based on the maximum peak value in the light distribution signal is within a predetermined range (±ΔD) from the object TA at a preset distance D1. In this way, the detection unit 40A can detect the object TA at a distance D1 from the main body 530.

[0158] Next, refer to Figure 24 This explains the effect of stray light in conventional optical sensors. Figure 24 This is a waveform diagram used to illustrate the effect of stray light in conventional optical sensors. Additionally, Figure 24 Conventional optical sensors are distance-setting photoelectric sensors, with a light-receiving section configured to acquire the light distribution signal of each pixel based on the received light. Furthermore, in Figure 24 In the diagram, the horizontal axis represents the pixels in the light-receiving area, and the vertical axis represents the amount of light received.

[0159] If the light emitted from the projection section contains stray light, the illumination range of the projection section expands, and the stray light is sometimes reflected by the aforementioned background (BG) and incident on the receiving section. Furthermore, if the surface of the object TA is packaged, and this package contains colors or patterns with different reflectivities, it is possible that these colors and patterns reflect stray light, and the reflected stray light is incident on the receiving section. In these cases, such as... Figure 24 As shown, the light distribution signal of the light-receiving part includes stray light (SLE) in addition to the main light component. Therefore, it is possible that the center of gravity in the light distribution signal changes, causing the calculated distance to change and leading to an incorrect determination of the presence or absence of the object TA.

[0160] In contrast, in the optical sensor 500 of this embodiment, the light-emitting unit 11 illuminates a light beam to the outside, and the light-receiving unit 21A is configured such that each of the multiple pixels can detect the amount of light received, and is configured to acquire a light-receiving amount distribution signal for each pixel based on the received light. The detection unit 40A detects the object TA based on the light-receiving amount distribution signal. As mentioned above, the light incident from the light source 12 provided on the bottom surface 13b to the side surface 13c is absorbed. Therefore, stray light component SLE in the light-receiving amount distribution signal can be suppressed, the center of gravity of the light-receiving amount signal can be reduced, and false detection of the object TA can be suppressed.

[0161] The exemplary embodiments of the present invention have been described above. According to one embodiment, the optical sensor 100 includes: a light-emitting unit 11 comprising a light-emitting light source 12 and a light-emitting lens 16 configured to focus the light from the light source 12; a light-receiving unit 21 that receives light; and a detection unit 40 that detects an object TA based on the received light. The light-emitting unit 11 further includes: a package 13, on the bottom surface 13b of a recess 13a formed in the package 13, the light source 12 being disposed thereon; and a resin 14 having light transmittance and covering the light source 12, the side surface 13c of the recess 13a comprising a material that absorbs the light from the light source 12. Thus, light incident from the light source 12 disposed on the bottom surface 13b onto the side surface 13c is absorbed, thereby absorbing stray light that may be generated, including stray light that includes the side surface 13c in its generation path and is a major factor. Therefore, stray light can be reduced, and the decrease in the S / N ratio can be suppressed. Furthermore, the visual confirmability of the spot of the main light illuminating the object TA can be improved.

[0162] Furthermore, the embodiments described above are for ease of understanding of the present invention and are not intended to limit or explain the present invention. The present invention can be modified / improved without departing from its spirit, and its equivalents are also included in the present invention. That is, any appropriate design changes made to the embodiments by those skilled in the art, as long as they possess the features of the present invention, are also included within the scope of the present invention. For example, the elements, their configurations, materials, conditions, shapes, dimensions, etc., possessed in each embodiment are not limited to the illustrative content and can be appropriately modified. Moreover, the embodiments are illustrative, and it goes without saying that partial substitutions or combinations of the structures shown in different embodiments are possible; as long as they contain the features of the present invention, these are also included within the scope of the present invention.

[0163] (Postscript)

[0164] 1. An optical sensor 100, 200, 300, 400, 500, comprising:

[0165] The light-emitting part 11 includes a light source 12 that emits light and a light-emitting lens 16 configured to focus the light from the light source 12.

[0166] Light receiving parts 21 and 21A receive light; and

[0167] Detection units 40 and 40A detect the object TA based on the received light.

[0168] The projection section 11 further includes: a package 13, wherein the light source 12 is disposed on the bottom surface 13b of the recess 13a formed in the package 13; and a resin 14, which is transparent and covers the light source 12.

[0169] The side surface 13c of the recess 13a contains a material that absorbs light from the light source 12.

Claims

1. An optical sensor, comprising: The light-emitting part includes a light source that emits light and a light-concentrating element configured to focus the light from the light source; The light-receiving part receives light; and The detection unit detects the object based on the received light. The light-projecting part further includes: an encapsulation, wherein the light source is disposed on the bottom surface of a recess formed in the encapsulation; and a resin that is translucent and covers the light source. The sides of the recess contain a material that absorbs the light from the light source.

2. The optical sensor according to claim 1, wherein, The side surface is connected to the bottom surface, and the angle between the side surface and the bottom surface is greater than 90 degrees.

3. The optical sensor according to claim 1, wherein, The reflectivity of the side surface to the light from the light source is less than 10%.

4. The optical sensor according to claim 1, wherein, The side surface is rough.

5. The optical sensor according to claim 1, wherein, The package is formed from a material that absorbs the light from the light source.

6. The optical sensor according to claim 1, wherein, The package is formed of a material that absorbs the light from the light source, and has a metal electrode pattern on the surface of the bottom surface, with the light source connected to the metal electrode pattern.

7. The optical sensor according to claim 1, wherein, The light-projecting part and the light-receiving part are separate frames. The light-projecting part faces outward to illuminate the light beam. The light-receiving part is configured to receive light emitted from the light-projecting part. The detection unit detects the object based on changes in the amount of light received.

8. The optical sensor according to claim 1, wherein, The light-projecting part and the light-receiving part are arranged in a common frame. The light-projecting part illuminates the beam of light towards the retroreflector. The light-receiving part is configured to receive light reflected by the retroreflector. The detection unit detects the object based on changes in the amount of light received.

9. The optical sensor according to claim 1, wherein, The light-projecting part and the light-receiving part are arranged in a common frame. The light-projecting part faces outward to illuminate the light beam. The light-receiving part has a light-receiving field of view and is configured to receive reflected light from the region where the light beam intersects with the light-receiving field of view. The detection unit detects the object based on changes in the amount of light received.

10. The optical sensor according to claim 9, wherein, The light-receiving axis of the light-receiving part and the light-projecting axis of the light-projecting part are intersected in such a way that the area where the light beam intersects with the field of view of the light-receiving part is limited.

11. The optical sensor according to claim 1, wherein, The light-projecting part faces outward to illuminate the light beam. The light-receiving unit is configured such that each of the multiple pixels can detect the amount of light received, and is configured to acquire the light distribution signal of each pixel in response to the received light. The detection unit detects the object based on the light distribution signal.

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