JP2013246048A - Distance measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact and inexpensive distance measuring device capable of highly accurately measuring a distance without performing calibration each time before measurement.SOLUTION: A part of light output from an infrared LED 2 is used as reference light, and passed through a reflection plate 15 formed in a light receiving side lens 13 to be guided to a position sensitive detector (PSD) of an image sensor 3. A deviation amount between the light receiving side lens and the PSD is detected to correct the position of reflected light for measurement. Thus, a distance from an object is accurately measured.

Description

  The present invention relates to an optical distance measuring device that detects the presence of an object to be measured within a measurable range and the distance to the object to be measured.

  2. Description of the Related Art Conventionally, an optical distance measuring device is used for various applications in order to measure a distance from a target object that is an object to be measured by a non-contact method. For example, it is installed in a toilet to detect the entry / exit of a user, or is installed in a projector to measure the distance between the screen and the lens when the projection screen is focused, or is installed in a robot such as an automatic vacuum cleaner. An optical distance measuring device (hereinafter also referred to as a distance measuring sensor) is used to detect an obstacle in advance and perform an avoidance action.

  In this distance measuring sensor, a product using a triangulation method is mainly used in view of its size and manufacturing cost. A distance measuring sensor of this type is reflected by a measured object (target object) out of light emitted from the light emitting element that emits light, a light emitting side lens that optically adjusts the emitted light, and the light emitted from the light emitting side lens. A light receiving side lens for collecting the reflected light and a light receiving element for detecting the light collected by the light receiving side lens.

  FIG. 4 shows a schematic configuration of an optical distance measuring sensor based on the triangulation method. This optical distance measuring sensor includes a light emitting unit composed of a light emitting side lens 51 and an LED (Light Emitting Diode) 52 as a light emitting element, and a light receiving side lens 53 and a PSD (semiconductor position) as a light receiving element. The light-receiving part comprised from the detection element: Position Sensitive Detector) 54 is arrange | positioned along with the fixed space | interval. Then, the light from the LED 52 is condensed via the light emitting side lens 51 and irradiated to a target object (not shown) in front of the distance measuring sensor, and the reflected light returned from the target object is reflected. A distance measuring sensor that utilizes the fact that the light receiving position of the reflected light on the light receiving area of the PSD 54 depends on the distance from the distance measuring sensor to the target object. The distance between the target object and the target object is calculated. The light receiving position on the light receiving area of the PSD 54 is determined by the ratio of the output currents from the two output terminals provided on the PSD 54 (current ratio output value). This is because the distance representing the light receiving position on the light receiving area of the PSD 54 and the current ratio output value have a relationship as shown in FIG.

  FIG. 5 shows the above-mentioned triangulation principle more specifically. The distance between the parallel optical axes of the light-emitting side lens 51 and the light-receiving side lens 53 is the baseline length S, and the focal point of the light-receiving side lens 53 is shown in FIG. The distance is f, and the distance between the LED 52 and the target object 55 is L. Then, light from the LED 52 is irradiated onto the target object 55 via the light emitting side lens 51, and reflected light from the target object 55 enters the light receiving position Rx of the PSD 54 via the light receiving side lens 53. The distance between the light receiving position Rx of the reflected light of the PSD 4 and the optical axis of the light receiving lens 53 is x.

Then, by the principle of triangulation,
L = S · f / x (Formula 1)
Thus, the measurement accuracy mainly depends on the accuracy of the base line length S and the distance x between the optical axis of the light receiving side lens 53 and the light receiving position Rx on the PSD 54.

  On the other hand, the incident position (light receiving position) Rx of the reflected light on the PSD 54 becomes closer to the LED 52 when the distance L between the LED 52 and the target object 55 increases, and when the distance between the LED 52 and the target object 55 decreases. It is far from. At this time, the distance L from the LED 52 to the target object 55 and the incident position Rx of the reflected light on the PSD 54 have a one-to-one correspondence as can be seen from FIG. Further, the distance representing the light receiving position Rx in the light receiving region on the PSD 54 and the current ratio output value of the PSD 54 have a one-to-one correspondence as shown in FIG. Therefore, the light receiving position Rx on the PSD 54 is calculated from the current ratio output value of the PSD 54, and it is assumed that the horizontal positional relationship between the light receiving side lens 53 and the PSD 54 at this time is the same as the initial setting and there is no error. The distance L from the LED 52 to the target object 55, that is, the distance L from the distance measuring sensor to the target object 55 can be calculated using the relationship shown in (Formula 1).

  In the triangulation method, the accuracy of distance measurement depends on the distance between the light emitting part and the light receiving part in principle, but with a small distance measuring sensor with a distance of 1 cm, a target object with a distance of 150 cm is measured with an accuracy of about 10%. In order to do this, the detection accuracy of the light receiving position Rx of the reflected light is required to be 1 μm or less.

  However, if the PSD 54 is shifted relative to the light receiving side lens 53 in the horizontal direction in FIG. 5 due to the influence of temperature, humidity, stress, etc., the current ratio output value of the PSD 54 is the optical axis of the light receiving side lens 53 and the PSD 54. Since the distance x to the upper light receiving position Rx is not correctly expressed, the distance L cannot be detected with high accuracy.

  As described above, in the triangulation method, in distance measurement, it is important to accurately detect the distance x and the base line length S of the incident position Rx of the reflected light on the light receiving area of the PSD 54 with respect to the optical axis of the light receiving side lens 53. However, since the relationship shown in FIG. 5 is determined only by the positional relationship of each component, in order to accurately determine the distance L between the target object 55 and the distance measuring sensor, the positional relationship is accurately determined. You have to decide high.

  Of course, when designing and manufacturing a distance measuring sensor, the positions of the LED 52 as the light emitting element, the PSD 54 as the light receiving element, the light emitting side lens 51, the light receiving side lens 53, etc. are set in advance. The relationship between the distance L to the target object 55 and the incident position Rx of the reflected light is uniquely determined.

  However, the positional relationship is affected by the deformation due to environmental changes (changes in temperature, humidity, stress, etc.) when the distance sensor is mounted on the final product and after use, as well as the assembly accuracy when manufacturing the distance sensor. Change, resulting in errors in distance measurement. In particular, due to the principle of triangulation, the influence of the position change of the light receiving element such as the PSD 54 on the light receiving side lens 53 is the largest, and the curve of FIG. 6 is greatly shifted from the design value. For this reason, there is a problem that the distance measurement value of the distance measuring sensor deviates from the actual distance.

  In order to correct this effect, there is usually a method in which an object is placed at a known distance in advance and measured before the distance is measured, and the deviation is calculated from the measured value and calibrated. . However, performing such calibration every time is very complicated in actual use, impairs convenience, and there is a problem that the calibration is wasted if the environment changes after calibration.

  Therefore, conventionally, as a distance measuring sensor, there is one described in Japanese Patent Laid-Open No. 2004-317202 (Patent Document 1). This distance measuring sensor is calibrated before shipment, and the individual constant and temperature coefficient specific to each distance measuring sensor are obtained and stored in the microcomputer. The calculated triangulation value is corrected based on the ambient temperature detected by the built-in temperature sensor.

  However, since the conventional distance measuring sensor corrects the calculated value of the triangular distance measuring according to the ambient temperature detected by the temperature sensor, the error due to the temperature change can be reduced, but the temperature sensor is required. In addition to increasing the size and cost, there is a problem that the influence of humidity and stress cannot be corrected.

JP 2004-317202 A

  Therefore, the problem of the present invention is that it does not require a temperature sensor, is small and inexpensive, and corrects the influence of temperature, humidity, stress, etc. without performing calibration work every time, and accurately measures the distance. An object of the present invention is to provide a distance measuring device that can be used.

In order to solve the above problems, the distance measuring device of the present invention is:
A light-emitting element, a light-receiving side lens, and a light-receiving element capable of detecting a light-receiving position are received by the light-receiving element via the light-receiving side lens. In the distance measuring device that measures the distance between the target object and the light emitting element by the triangulation method,
Reference light path forming means that is fixed directly or indirectly to the light receiving side lens and that forms a reference light path that guides the light emitted from the light emitting element to the light receiving element without passing through the target object. It is characterized by.

  According to the distance measuring apparatus having the above-described configuration, the light emitted from the light emitting element is not routed through the target object by the reference optical path forming unit fixed directly or indirectly to the light receiving side lens. Then, it enters the light receiving element as reference light.

  Since the reference optical path forming means is directly or indirectly fixed to the light receiving side lens, if the position of the light receiving side lens is shifted relative to the light receiving element due to the influence of temperature, humidity, stress, etc., the reference The optical path forming means is also relatively shifted by the same amount. Therefore, the light receiving position of the reference light on the light receiving element is also shifted according to the amount of deviation of the relative position between the light receiving side lens and the light receiving element.

  Therefore, it is possible to detect the shift amount of the relative position between the light receiving side lens and the light receiving element from the shift amount of the reference light receiving position on the light receiving element. Therefore, even if no complicated calibration work is required after factory shipment, using this deviation amount, the light receiving position on the light receiving element of the reflected light from the target object is corrected, and changes in temperature, humidity, stress, etc. The distance to the target object can be accurately detected without being affected.

  The distance measuring device of the present invention does not use a sensor such as a temperature sensor, and is therefore small and inexpensive.

  In one embodiment, the reference optical path forming means is a reflector.

  In the above embodiment, since the reference optical path forming means is a reflecting plate, the reference optical path can be formed easily and inexpensively.

  In one embodiment, the reflector has a metal film that reflects the light.

  In the above embodiment, since the reflection plate has a metal film that reflects light, the reflection plate can be manufactured easily and inexpensively, and light can be reflected efficiently.

  In one embodiment, the reflecting plate has a concave surface, and condenses light at the concave surface and directs the light toward the light receiving element.

  According to the embodiment, the concave surface of the reflector condenses light as reference light and makes it incident on the light receiving element, so that the light spot of the reference light on the light receiving element is small and strong, and the light The position of the center of gravity of the spot can be obtained accurately, and thus the amount of deviation can be obtained accurately.

  In one embodiment, the measurement light receiving region of the light receiving element that receives the light reflected from the target object via the light receiving side lens, and the light emitted from the light emitting element is transmitted to the reference optical path forming unit. The reference light receiving area of the light receiving element that is received via is arranged so as not to overlap.

  According to the embodiment, since the measurement light receiving region of the light receiving element and the reference light receiving region of the light receiving element do not overlap with each other, the incident position on the light receiving element of the measurement light, which is light reflected from the target object, The incident position on the light receiving element of the reference light, which is the light that passes through the reference optical path forming means, can be detected separately and is not confused. Therefore, the incident position of the measurement light and the incident position of the reference light can be detected with high accuracy. Thus, highly accurate measurement can be performed.

  In one embodiment, the measurement light-receiving area and the reference light-receiving area of the light-receiving element are arranged in parallel with the alignment direction of the light-emitting element and the light-receiving element.

  In the embodiment, the light incident position of the light receiving element is displaced in the alignment direction of the light emitting element and the light receiving element, whereas the measurement light receiving area and the reference light receiving area of the light receiving element are Since the light emitting element and the light receiving element are arranged in parallel with each other in the alignment direction, the light receiving area for measurement and the reference can be used effectively, and there are few useless light receiving areas. If the light receiving element for measurement and the light receiving area for reference of the light receiving element are not arranged in parallel with the alignment direction of the light emitting element and the light receiving element, for example, arranged in a direction crossing the alignment direction. The measurement light cannot enter the measurement light reception area, and the measurement light reception area does not enter, or the reference light cannot enter the reference light reception area and the measurement light reception area. In other words, a useless portion where no light enters is generated in the region and the light receiving region for reference.

  In one embodiment, a light shielding plate for preventing light from the light emitting element from entering the light receiving element as stray light is provided, and a hole through which the reference light path passes is provided in the light shielding plate.

  In the above embodiment, since a hole through which the reference optical path passes is provided in a light shielding plate that prevents light from the light emitting element from entering the light receiving element as stray light, stray light is prevented from entering the light receiving element. And a reference optical path can be easily formed.

  In one embodiment, a shift amount of a relative position between the light receiving side lens and the light receiving element is detected based on a light receiving position of light guided on the light receiving element through the reference optical path by the reference optical path forming unit. To do.

  In one embodiment, a light receiving position on the light receiving element of reflected light from the target object is corrected based on the amount of deviation, and a distance between the target object and the light emitting element is calculated.

  In the above embodiment, the light receiving position on the light receiving element of the reflected light from the target object is corrected based on the shift amount of the relative position between the light receiving side lens and the light receiving element, and the target object and the light emitting element are corrected. Therefore, even if there is a shift in the relative position between the light receiving side lens and the light receiving element due to changes in the environment such as temperature, humidity, and stress, complicated calibration is required for each measurement. The distance can be accurately measured.

  In one embodiment, it is possible to select whether or not to correct the light receiving position on the light receiving element of the reflected light from the target object based on the amount of deviation.

  In one embodiment, an arithmetic unit that corrects a light receiving position on the light receiving element of reflected light from the target object based on the shift amount and calculates a distance from the target object is integrated with the light receiving element. Is provided.

  In the embodiment, an arithmetic unit that corrects the light receiving position on the light receiving element of the reflected light from the target object based on the shift amount and calculates a distance from the target object is integrated with the light receiving element. The structure is small and compact.

  According to the present invention, a distance that does not require a temperature sensor, is small and inexpensive, and can accurately measure the distance by correcting the influence of temperature, humidity, stress, etc. without performing calibration work each time. A measuring device can be realized.

It is a schematic front view of the distance measuring apparatus of 1st Embodiment of this invention. It is a schematic sectional side view of the distance measuring apparatus of the said 1st Embodiment. It is a schematic plan view of the image sensor of the distance measuring device. It is a schematic front view of the distance measuring device of 2nd Embodiment of this invention. It is a schematic front view of the conventional distance measuring device. It is explanatory drawing of the principle of a triangulation method. It is the schematic explaining the relationship between distance and a current ratio output value.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1A is a front view of the distance measuring device according to the first embodiment of the present invention, and FIG. 1B is a side sectional view of the distance measuring device.

  As shown in FIG. 1A, the distance measuring device according to the first embodiment includes an infrared LED 2 and an image sensor 3 that emit infrared light as an example of a light emitting element on a substrate 1. The infrared LED 2 and the image sensor 3 are electrically connected to a wiring pattern (not shown) provided on the substrate 1. Further, the image sensor 3 is connected to an external terminal 5, and the image sensor 3 is connected to a power source and an external circuit via the external terminal 5.

  As shown in FIG. 2, the image sensor 3 includes, on a substrate portion 31, a PSD (Position Sensitive Detector) 32 as an example of a light receiving element and a DSP (Digital Signal Processor: an example of an arithmetic device). Digital Signal Processor) 33, nonvolatile memory 34, and power supply circuit 35 are mounted. The PSD 32 has a measurement light receiving region 32a and a reference light receiving region 32b.

  As shown in FIG. 1A, an exterior case 6 is formed integrally with a substrate 1 on which the infrared LED 2 and the image sensor 3 are mounted by molding of an infrared shielding resin that blocks infrared rays. At the same time, in order to prevent the infrared light emitted from the infrared LED 2 between the infrared LED 2 and the image sensor 3 on the substrate 1 from entering the image sensor 3 as stray light at random. An infrared light shielding plate 7 made of an infrared light shielding resin for preventing stray light is formed. A hole 8 is formed in a part of the infrared light shielding plate 8 with a mold.

  A cap 10 made of an infrared transmitting resin that transmits infrared rays is attached to the upper ends of the outer case 6 and the infrared light shielding plate 7, and the infrared LED 2 on the substrate 1 is formed by the cap 10 and the outer case 6. And the image sensor 3 are sealed.

  The cap 10 includes a flat plate portion 11, a light emitting side lens 12, and a light receiving side lens 13, which are formed by integral molding of an infrared transmitting resin using a mold. The flat plate portion 11 is in close contact with the upper ends of the outer case 6 and the infrared light shielding plate 7.

  As shown in FIG. 1A, the flat plate portion 11 in front of the light receiving side lens 13 of the cap 10 and the horizontal side of the light receiving side lens 13 of the cap 10 in FIG. A plate 15 is provided. The reflecting plate 15 is made of an infrared transmitting resin, is located in the vicinity of the light receiving side lens 13, and is formed integrally with the light receiving side lens 13. The reflector 15 may be directly fixed to the light receiving side lens 13 or may be indirectly fixed with respect to other members.

  A metal film (not shown) that reflects infrared rays is formed on a part of the lower surface of the reflecting plate 15 by vapor deposition or the like. A straight line connecting the metal film and the infrared LED 2 passes through the hole 8 of the infrared light shielding plate 7, and a part of the infrared light emitted from the infrared LED 2 is a part of the infrared light shielding plate 7. The light spot 17 is formed in the reference light receiving region 32b of the PSD 32 shown in FIG. 2 by being reflected by the metal film of the reflector 15 through the hole 8.

  The reflection plate 15 as the reference optical path forming means passes through the hole 8 of the infrared light shielding plate 7 from the infrared LED 2, passes through the reflection plate 15, and reaches the reference light receiving region 32 b of the PSD 32. Form. This reference optical path does not pass through a measurement target object (not shown).

  A part of the infrared light emitted from the infrared LED 2 passes through the light-emitting side lens 12, is reflected by the object to be measured, passes through the light-receiving side lens 13, and is received by the PSD 32 shown in FIG. The light spot 18 is formed in the region 32a.

  Here, after the manufacturing of the distance measuring apparatus according to the first embodiment, a measurement operation is performed once on a calibration target object (not shown) placed at a known distance (for example, 150 cm). At this time, the light is emitted from the LED 2, passes through the hole 8, is reflected by the metal film of the reflecting plate 15, and is emitted from the LED 2 and the position of the infrared light reference light spot 17 incident on the PSD 32 of the image sensor 3. Both the positions of the light spot 18 for measuring infrared light reflected by the calibration target object, passing through the light-receiving side lens 13 and incident on the PSD 32 of the image sensor 3 through the light-emitting side lens 12. Measure each. In this measurement, the DSP 33 calculates each current ratio output value of the PSD 32, and determines the positions of the reference light spot 17 and the measurement light spot 18 on the PSD 32 based on the current ratio output value. This position is written in a nonvolatile memory (not shown) built in the DSP 33 and is used as the initial value of this distance measuring device. This initial setting is performed once for each distance measuring device before shipment from the factory.

  The distance measuring apparatus having the above configuration operates as follows.

  First, as in the case of the initial setting, the infrared light reference light spot that is emitted from the LED 2, passes through the hole 8, is reflected by the metal film of the reflecting plate 15, and enters the PSD 32 of the image sensor 3. The red light emitted from the LED 2, reflected by the light-emitting side lens 12, reflected from the target object (at an arbitrary position to be measured), and incident on the PSD 32 of the image sensor 3 through the light-receiving side lens 13. Both the position of the light spot 18 for measuring external light and the position of the light spot 18 are measured.

  Then, the DSP 33 determines whether or not the position of the reference light spot 17 of the light reflected by the metal film of the reflecting plate 15 and incident on the PSD 32 of the image sensor 3 has changed from the initial value. In this case, the amount of displacement Δx of the relative position between the light receiving side lens 13 and the image sensor 3 is calculated from the difference between the position and the initial value. The above difference is substantially proportional to the amount of deviation Δx of the relative position between the light receiving side lens 13 and the image sensor 3. This deviation amount Δx is caused by various factors such as temperature, humidity, and stress from the initial setting.

  Thereafter, the value representing the position of the light spot 18 for measuring the infrared light reflected from the target object, passing through the light receiving side lens 13 and incident on the PSD 32 of the image sensor 3 is corrected by the deviation Δx. The distance is converted into distance data using the relationship between the preset distance and the reflected light position, and output. The relationship between the distance and the reflected light position is basically the same as the above (Equation 1) based on the principle of triangulation.

  According to the distance measuring device, the reflector 3 and the light receiving side lens 13 are displaced in the same lateral direction with respect to the image sensor 3, so that the relative position shift amount Δx between the light receiving side lens 13 and the image sensor 3. Can be obtained based on the position of the reference light spot 17 of the light reflected by the reflecting plate 15 and incident on the PSD 32 of the image sensor 3. Therefore, the distance measuring apparatus according to the first embodiment is different from the case where the positional relationship between the component parts is deviated due to temperature, stress, humidity, or the like when the calibration is performed in the initial setting after the manufacturing and before the factory shipment. The incident position of the measurement light spot 18 incident on the PSD 32 is corrected by the amount of deviation Δx obtained by the displacement from the initial setting of the reference light spot 17 without performing complicated calibration work. The distance to the target object can be accurately obtained.

  In addition, the distance measuring device according to the first embodiment is small and inexpensive because it does not require an expensive temperature sensor or the like that was necessary in the prior art.

  In the first embodiment, since the reference optical path forming means is the reflector 15, the reference optical path can be formed easily and inexpensively.

  In the first embodiment, the reflecting plate 15 is formed by vapor deposition and has a metal film that reflects infrared light. Therefore, a reflecting plate having a high reflecting ability can be manufactured easily and inexpensively.

  In the first embodiment, the measurement light-receiving area 32a of the PSD 32 that receives the infrared light reflected from the target object via the light-receiving side lens 13 and the light emitted from the LED 2 are reflected on the reflection plate 25. Since the reference light receiving area 32b of the PSD 32 received via the reference light receiving area 32b does not overlap, the measurement light spot 18 of the measurement light, which is the light reflected from the target object, and the reference light from the reflector 15 Therefore, the reference light spot 17 can be detected separately and is not confused. Therefore, the measurement light incident position and the reference light incident position can be detected with high accuracy, and highly accurate measurement can be performed.

  In the first embodiment, the measurement light receiving region 32a and the reference light receiving region 32b of the PSD 32 are arranged in parallel with the alignment direction of the infrared LED 2 and the PSD 32. Each area can be used effectively, and there are few useless light receiving areas. If the PSD light receiving area 32a and the reference light receiving area 32b of the PSD 32 are not arranged in parallel with the alignment direction of the infrared LED 2 and the PSD 32, for example, arranged in a direction crossing the alignment direction. The measurement light cannot enter the measurement light-receiving region 32a and protrude from the measurement light-receiving region 32a, or the reference light cannot enter the reference light-receiving region 32b and protrude from the reference light-receiving region 32b. In addition, useless portions where no light enters are generated in the measurement light receiving region 32a and the reference light receiving region 32b.

  In the first embodiment, the light shielding plate 7 that prevents the light from the infrared LED 2 from entering the PSD 32 as stray light is provided, and the hole 8 through which the reference optical path passes is provided in the light shielding plate 7. Can be prevented, and the reference optical path can be easily formed.

  In the first embodiment, the DSP 33 that corrects the light receiving position on the PSD 32 of the reflected light from the target object based on the deviation Δx and calculates the distance to the target object is provided integrally with the PSD 32. Therefore, the structure becomes small and compact.

  FIG. 3 is a sectional view of a distance measuring apparatus according to the second embodiment of the present invention. In FIG. 3, the same components as those of the first embodiment shown in FIGS. 1A, 1B and 2 are denoted by the same reference numerals, detailed description thereof is omitted, and different components are described below. .

  In the second embodiment, as shown in FIG. 3, in addition to providing the reflector 25 as an example of the reference optical path forming means in front of the light receiving side lens 13, the reference optical path forming means is also provided in front of the light emitting side lens 12. As an example, a reflector 26 is provided. Similar to the reflector 15 of the first embodiment, a metal film (not shown) that reflects infrared rays is formed on a part of each of the reflectors 25 and 26 by vapor deposition or the like.

  Further, an infrared light shielding plate 27 made of an infrared light shielding resin having a lower height than the infrared light shielding plate 7 for preventing stray light of the first embodiment shown in FIG. 1A is provided.

  The flat plate portion 21 of the cap 20 made of infrared transmitting resin that transmits infrared rays is provided with a protruding portion 21 a that protrudes downward, and the protruding portion 21 a is in contact with the infrared light shielding plate 27.

  A part of the infrared light emitted from the infrared LED 2 is reflected by the metal film of the reflection plate 26, passes through the protrusion 21 a, is reflected by the metal film of the reflection plate 25, and enters the image sensor 3. It has become.

  Then, similarly to the first embodiment, the light spot 17 is formed in the reference light receiving region 32b of the PSD 32 of the image sensor 3 shown in FIG.

  In the second embodiment, the same effect as the first embodiment can be obtained.

  In the first and second embodiments, the reflection plates 15 and 25 are formed integrally with the light receiving side lens 13 and made of the same infrared transmitting resin, but the reflection plate is formed separately from the light receiving side lens 13. Alternatively, the cap 10 may be formed of a material that is different from the infrared transmitting resin and reflects infrared light. In short, the light-receiving side lens 13 and the reflectors 15 and 25 may be positioned in the vicinity of each other and fixed directly or indirectly including integration so that the positional relationship between them does not change.

  Further, although not shown, the reflecting plates 15, 25, 26 formed beside the light emitting side lens 12 and the light receiving side lens 13 may have a concave mirror structure. In this way, the size of the reference light can be reduced and the intensity can be increased, and the position of the center of gravity of the light spot of the reference light can be obtained more accurately.

  In the first and second embodiments, the reflectors 15, 25, and 26 are described as the reference optical path forming means. However, the reference optical path forming means may be a prism or a diffraction grating.

  In the first and second embodiments, the PSD 32 is used as an example of the light receiving element. However, as a light receiving element capable of detecting the light receiving position, a CMOS (complementary metal oxide semiconductor) image sensor, a CCD (charge coupled device). A solid-state imaging device such as an image sensor may be used.

  In the first and second embodiments, the DSP 33 is used as the arithmetic device, but a CPU (central processing unit) may be used.

  Moreover, although LED2 was used as a light emitting element in the said 1st, 2nd embodiment, you may use a semiconductor laser. The light emitting side lens may be omitted.

  Although not shown, a switch may be provided to select whether or not to correct the light receiving position on the light receiving element of the reflected light from the target object based on the deviation amount Δx. .

2 Infrared LED
3 Image sensor 7 Light-shielding plate 8 Hole 12 Light-emitting side lens 13 Light-receiving side lens 15, 25, 26 Reflector 32 PSD
32a Light receiving area for measurement 32b Light receiving area for reference 33 DSP

Claims (11)

A light-emitting element, a light-receiving side lens, and a light-receiving element capable of detecting a light-receiving position are received by the light-receiving element via the light-receiving side lens. In the distance measuring device that measures the distance between the target object and the light emitting element by the triangulation method,
Reference light path forming means that is fixed directly or indirectly to the light receiving side lens and that forms a reference light path that guides the light emitted from the light emitting element to the light receiving element without passing through the target object. A distance measuring device characterized by.   2. The distance measuring device according to claim 1, wherein the reference optical path forming means is a reflecting plate.   The distance measuring device according to claim 2, wherein the reflector includes a metal film that reflects the light.   4. The distance measuring device according to claim 2, wherein the reflecting plate has a concave surface, and condenses light at the concave surface and directs the light toward the light receiving element.   5. The distance measuring device according to claim 1, wherein a light receiving region for measurement of the light receiving element that receives the light reflected from the target object via the light receiving side lens, and the light emitting element. A distance measuring device arranged so as not to overlap a reference light receiving region of the light receiving element that receives the emitted light via the reference optical path forming means.   6. The distance measuring apparatus according to claim 5, wherein the light receiving area for measurement and the light receiving area for reference of the light receiving element are arranged in parallel with the alignment direction of the light emitting element and the light receiving element. Distance measuring device. In the distance measuring device according to any one of claims 1 to 6,
A distance measuring apparatus comprising: a light shielding plate that prevents light from the light emitting element from entering the light receiving element as stray light; and a hole through which the reference optical path passes. In the distance measuring device according to any one of claims 1 to 7,
Detecting a shift amount of a relative position between the light receiving side lens and the light receiving element on the basis of a light receiving position of light guided onto the light receiving element through the reference optical path by the reference optical path forming unit; Distance measuring device. The distance measuring device according to claim 8, wherein
A distance measuring apparatus that corrects a light receiving position of the reflected light from the target object on the light receiving element based on the shift amount, and calculates a distance between the target object and the light emitting element. The distance measuring device according to claim 9,
A distance measuring device that can select whether or not to correct the light receiving position on the light receiving element of the reflected light from the target object based on the deviation amount. The distance measuring device according to claim 9 or 10,
An arithmetic device for correcting the light receiving position on the light receiving element of the reflected light from the target object based on the deviation amount and calculating the distance from the target object is provided integrally with the light receiving element. A distance measuring device characterized by that.

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