JP2014048139A - Range finder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a range finder capable of preventing false detection by suppressing noise caused by outside light.SOLUTION: A range finder 10 includes: a light emission part 31 for emitting light to a measured object 20; light reception parts 32a, 32b for receiving the light reflected by the measured object 20; and a light interception part 22 for intercepting outside light. The light interception part 22 intercepts an optical path 40a between the light emission part 31 and the measured object 20, an optical path 40b between the measured object 20 and the light reception part 32a, and an optical path 40c between the measured object 20 and the light reception part 32b from the outside light.

Description

  The present invention relates to a distance measuring device, and more particularly, to an optical distance measuring device that emits light from a light emitting unit toward an object to be measured and receives the reflected light to measure the distance.

  Currently, optical distance measuring devices that measure the distance between a light emitting unit and an object to be measured by emitting light from the light emitting unit toward the object to be measured as a distance measuring device that measures the distance to the object to be measured. Are known. Such an optical distance measuring device is used to detect opening / closing of a sunroof or sunroof shade of a vehicle.

  Patent Document 1 discloses a distance measuring device for detecting opening and closing of a sunroof of a vehicle. FIG. 9 is a perspective view of the conventional distance measuring device 110 described in Patent Document 1 as seen from inside the vehicle. As shown in FIG. 9, a sunroof 151 that can be opened and closed by sliding is provided on the ceiling 150 of the vehicle. In the distance measuring device 110 of the conventional example, an infrared light emitting unit 131 is provided on the ceiling 150 of the vehicle, and a light receiving unit 132 that receives infrared light is provided on the sunroof 151. The light emitting unit 131 and the light receiving unit 132 are arranged to face each other, and the light receiving unit 132 moves as the sunroof 151 is opened and closed, so that the distance between the light emitting unit 131 and the light receiving unit 132 changes. The open / close state of the sunroof 151 can be detected based on the intensity of infrared light received by the light receiving unit 132.

  Further, in the case of a structure in which the sunroof 151 is slid as shown in FIG. 9, a storage area substantially equal to that of the sunroof 151 is necessary, and thus there is a problem that the aperture ratio cannot be increased. In order to solve this, a method is known in which a skylight for taking in external light is provided on the ceiling of the vehicle, and a sunroof shade using a fabric or a film is provided on the skylight portion. FIG. 10 shows a roll type sunroof shade 251. According to this, when external light is shielded, the skylight 252 can be covered and shielded by the unfolded portion 251b drawn from the storage portion 251a of the sunroof shade 251. And when taking in external light, the storage part 251a can be wound up in roll shape, and the sunroof shade 251 can be accommodated. Therefore, the storage portion 251a can be reduced and the area of the skylight 252 can be increased.

  Further, as shown in FIG. 10, a distance measuring device 210 that detects opening and closing of the sunroof shade 251 is provided. In the distance measuring device 210, a light emitting unit 231 and a light receiving unit 232 are provided on the ceiling 250 of the vehicle, and infrared light emitted from the light emitting unit 231 is reflected at the end of the developed portion 251b of the sunroof shade 251. The reflected light is received by the light receiving unit 232. The open / close position of the sunroof shade 251 can be detected based on the received light intensity at the light receiving unit 232.

Japanese Utility Model Publication No. 3-64821

  However, in the distance measuring device 210 as shown in FIG. 10, the distance between the light emitting portion 231 and the end of the developed portion 251b is measured by the reflected light at the end of the developed portion 251b of the sunroof shade 251. Therefore, the light path 240a from the light emitting unit 231 and the end of the developed part 251b and the light path 240b from the end of the developed part 251b to the light receiving unit 232 are provided so as to cross the external light incident from the skylight 252. Moreover, the light emission part 231, the light-receiving part 232, and the edge part of the expansion | deployment part 251b are provided in the vicinity of the skylight 252. FIG. Therefore, in the conventional distance measuring device 210, there is a problem that erroneous detection is likely to be influenced by external light.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems and provide a distance measuring device that can prevent false detection by suppressing noise caused by external light.

  The distance measuring device of the present invention has a light emitting unit that emits outgoing light to the object to be measured, a light receiving unit that receives reflected light reflected by the object to be measured, and a light shielding unit that blocks external light, The light shielding unit shields an optical path from the light emitting unit to the device under test and an optical path from the device under test to the light receiving unit from outside light. According to this, by providing the light shielding part, it is possible to suppress noise due to external light and prevent erroneous detection.

  In the distance measuring device of the present invention, a measurement object that can be stored and deployed, a light emitting unit that emits emitted light to a storage part that is stored in the light-shielding part of the measurement object, and the storage part is reflected A light-receiving part that receives reflected light, and a light-shielding part that shields an optical path from the light-emitting part to the storage part and from the storage part to the light-receiving part from outside light is provided, Based on the distance from the storage portion, the length of the unfolded portion of the object to be measured that is unshielded by the light shielding portion and is unshielded is detected.

  According to this, since the length of the developed part of the object to be measured is detected by measuring the distance between the light emitting part and the storage part, it is not necessary to directly measure the position of the developed part. Therefore, the light path from the light emitting part to the storage part and from the storage part to the light receiving part can be provided without crossing outside light, and the length of the development part can be detected. Further, since the distance from the light emitting unit to the storage portion is measured, the optical path between the light emitting unit and the storage portion can be provided shorter than the optical path between the light emitting unit and the deployment portion in the conventional distance measuring device. Therefore, it is easy to provide the light shielding part so as to shield the optical path from the light emitting part to the housing part and from the housing part to the light receiving part, and it is possible to suppress false detection by suppressing noise due to external light.

  It is preferable that the storage portion is formed in a roll shape by winding the object to be measured. According to this, the length of the developed portion can be easily calculated based on the distance between the light emitting portion and the storage portion of the object to be measured.

  It is preferable that the optical path is provided in a space formed by the light shielding part and the object to be measured. According to this, noise due to external light can be effectively suppressed and erroneous detection can be reliably prevented.

  An antireflection function is provided on the inner surface of the light shielding portion. According to this, since the light emitted from the light emitting unit and the light reflected by the object to be measured can be suppressed from being reflected by the light shielding unit, noise due to the reflected light from the light shielding unit is suppressed, and erroneous detection is prevented. be able to.

  According to the distance measuring apparatus of the present invention, it is possible to prevent erroneous detection by suppressing noise due to external light by providing a light shielding portion.

It is a perspective view which shows the distance measuring device in embodiment of this invention. (A) It is sectional drawing when it cut | disconnects by the II-II line | wire of FIG. 1, and it sees from the arrow direction, and is sectional drawing explaining the expansion | deployment state of a to-be-measured object. (B) It is sectional drawing explaining the accommodation state which accommodated the to-be-measured object. It is sectional drawing explaining the ranging method of the ranging apparatus of embodiment. It is sectional drawing which shows the distance measuring sensor in the distance measuring device of embodiment. It is a graph which shows the relationship between the distance of a light emission part and an accommodating part, and the intensity ratio of the light received by two light-receiving parts. It is a graph which shows the relationship between the distance of a light emission part and an accommodating part, and the intensity | strength of the light received by a light-receiving part. It is sectional drawing which shows the modification of the distance measuring device of embodiment. It is sectional drawing when the ranging apparatus of this embodiment is applied to the sunroof shade apparatus of a vehicle. It is a perspective view which shows the distance measuring device of a prior art example. It is a perspective view which shows the distance measuring apparatus of another prior art example.

  Hereinafter, a distance measuring apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a distance measuring device 10 of the present embodiment. FIG. 2A is a cross-sectional view taken along the line II-II in FIG. 1 and viewed from the direction of the arrow, and shows a developed state of the DUT 20. FIG. 2B is a cross-sectional view illustrating a stored state when the DUT 20 of FIG. 2A is stored.

  In the distance measuring device 10 of the present embodiment, the object to be measured 20 is formed in a sheet shape, and a flexible material such as a cloth or a resin film is used. As shown in FIGS. 2A and 2B, the DUT 20 is formed so that it can be stored and unfolded. In the unfolded state shown in FIG. 2A, the DUT 20 has a large area. It is pulled out to cover it. The developed part of the DUT 20 is defined as a developed part 20b. 2B, the object to be measured 20 is wound around the winding shaft 21 in a roll shape and stored in a small area. In this specification, a portion of the DUT 20 that is stored is referred to as a storage portion 20a. Such a distance measuring device 10 is used for a sunroof shade device for vehicles, for example.

  As shown in FIGS. 1 and 2, a light shielding portion 22 is provided so as to cover the storage portion 20 a of the object to be measured 20, and the light shielding portion 22 is located at a position facing the storage portion 20 a of the object to be measured 20. A distance measuring sensor 30 is provided. In the present embodiment, the light shielding portion 22 is a case formed of a material that does not transmit light, such as resin or metal.

  FIG. 3 is a cross-sectional view for explaining the distance measuring method of the distance measuring device 10 of the present embodiment. FIG. 4 shows a cross-sectional view of the distance measuring sensor 30. As shown in FIG. 4, the distance measuring sensor 30 of the present embodiment is configured to include a light emitting unit 31, a light receiving unit 32 a, and a light receiving unit 32 b that are installed on a substrate 33 at intervals. The substrate 33, the light emitting unit 31, the light receiving unit 32a, and the light receiving unit 32b are resin-molded with a sealing resin 35. The resin-molded substrate 33 is disposed in the case 34, and the case 34 is provided with openings at positions facing the light emitting unit 31, the light receiving unit 32a, and the light receiving unit 32b. An infrared light emitting diode is used for the light emitting unit 31 and infrared light having a peak wavelength of 940 nm can be emitted. Further, photodiodes are used for the light receiving unit 32a and the light receiving unit 32b, and the intensity of light received by the light receiving unit 32a and the light receiving unit 32b can be detected.

  As shown in FIG. 3, the distance measuring sensor 30 is provided on the inner surface of the light shielding portion 22 above the storage portion 20 a of the object to be measured 20. The light emitting part 31 emits outgoing light to the storage part 20a, and the light receiving part 32a and the light receiving part 32b receive the reflected light reflected by the storage part 20a of the outgoing light. The two light receiving parts 32a and 32b are arranged at a predetermined interval, and based on the intensity ratio of the light received by the two light receiving parts 32a and 32b, the light emitting part 31 and the storage part 20a are arranged. The distance can be detected. That is, if the reflectance of the object to be measured 20 with respect to infrared light is obtained, the relationship between the distance and the light intensity ratio can be obtained in advance, and the relationship between the light intensity ratio and the distance is measured. The distance can be detected based on the light intensity ratio.

  FIG. 5 is a graph showing the relationship between the distance between the light emitting unit 31 and the storage portion 20a and the intensity ratio of light received by the light receiving unit 32a and the light receiving unit 32b in the distance measuring device 10 of the present embodiment. The reflected light intensity ratio is calculated as D2 / D1 (%), where D1 is the intensity of light received by the light receiving unit 32a and D2 is the intensity of light received by the light receiving unit 32b. The light reflectance of the storage portion 20a was 50%. As shown in FIG. 5, the reflected light intensity ratio tends to increase as the distance between the light emitting unit 31 and the storage portion 20a increases. When the distance between the light emitting unit 31 and the storage portion 20a is in the range of 1 cm to 8 cm, the reflected light intensity ratio changes from 0 to about 90%. Based on this reflected light intensity ratio, the distance between the light emitting portion 31 and the storage portion 20a can be obtained.

  Further, in the present embodiment, two light receiving units 20 are provided, but even if there is one light receiving unit 20, the distance between the light emitting unit 31 and the storage portion 20a is detected based on the intensity of the reflected light. Can do. FIG. 6 is a graph showing the relationship between the distance between the light emitting unit 31 and the storage portion 20a and the intensity of light received by the light receiving unit 32a. As shown in FIG. 6, the reflected light intensity tends to decrease as the distance between the light emitting unit 31 and the storage portion 20a increases. In particular, the reflected light intensity greatly changes in the range of 1 cm to 6 cm between the light emitting portion 31 and the storage portion 20a. Compared with the distance measuring method shown in FIG. 5, the light emitting portion 31 and the storage portion 20a are separated from each other. It is effective in a range where the distance is small. Thus, even if there is one light receiving unit 20, the distance between the light emitting unit 31 and the storage portion 20a is obtained based on the reflected light intensity.

  It is preferable to use a material that reflects infrared light as the DUT 20. For example, the object to be measured 20 may be a metal material such as aluminum formed in a sheet shape, or a sheet material metal bonded to a cloth or a resin film. Alternatively, a resin film formed by mixing with a resin using a white oxide such as titanium oxide, a composite oxide containing titanium oxide, or the like can be used.

  In the present embodiment, by arranging the winding shaft 21 and the light emitting unit 31 at a predetermined distance, the total thickness of the storage portion 20a is obtained based on the distance between the light emitting unit 31 and the storage portion 20a. It is done. If the thickness of the DUT 20 is determined, the length of the storage portion 20a wound up can be obtained from the total thickness of the storage portion 20a. And the length of the expansion | deployment part 20b can be calculated | required by subtracting the storage part 20a from the whole length of the to-be-measured object 20. FIG. Therefore, based on the distance between the light emitting portion 31 and the storage portion 20a, it is possible to detect the length of the expanded portion 20b that is unshielded by the light shielding portion 22 of the device under test 20 and is spread outward. In addition, in this embodiment, since the storage part 20a is wound up in roll shape, the length of the storage part 20a can be calculated | required easily.

  As described above, since the distance between the light emitting unit 31 and the storage portion 20a is measured by the distance measuring sensor 30 and the length of the deployed portion 20b deployed in the object to be measured 20 is detected, There is no need to measure the position. Therefore, the optical paths 40a, 40b, and 40c from the light emitting unit 31 to the storage part 20a, from the storage part 20a to the light receiving part 32a, and from the storage part 20a to the light receiving part 32b can be provided without crossing outside light. The length of the portion 20b can be detected. Further, in the method of directly detecting the position of the developed portion as in the conventional examples shown in FIGS. 9 and 10, it is necessary to cover the entire object to be measured with the light shielding portion in order to prevent the influence of external light noise. It was n’t right. According to the distance measuring device 10 of the present embodiment, the storage portion 20a is stored in a roll in a small area, and the distance from the light emitting unit 31 to the storage portion 20a is measured. Therefore, the optical path 40a between the light emitting unit 31 and the storage portion 20a can be provided shorter than the optical path 240a between the light emitting unit 231 and the developed portion 251b in the conventional distance measuring device 210. Therefore, it is easy to provide the light shielding portion 22 so as to shield the optical paths 40a, 40b, and 40c, and it is possible to prevent erroneous detection by suppressing noise due to external light.

  In the present embodiment, the light emitting unit 31, the light receiving unit 32 a, the light receiving unit 32 b, and the storage portion 20 a are disposed inside the light shielding unit 22. However, the present invention is not limited thereto, and only the optical paths 40a, 40b, and 40c from the light emitting unit 31 to the housing part 20a, from the housing part 20a to the light receiving unit 32a, and from the housing part 20a to the light receiving unit 32b are removed by the light shielding unit 22. Even when light is shielded from light, the same effect can be obtained. For example, a configuration in which the distance measuring sensor 30 is provided on the outer surface of the light shielding unit 22, or a space formed by the light shielding unit 22 and the DUT 20 by covering the upper half or more of the storage portion 20 a shown in FIG. Even if it is the structure which provides the light-shielding part 22 so that the optical path 40a, 40b, 40c is provided in the inside, it can shield external light and can prevent misdetection.

  Further, the position where the distance measuring sensor 30 is installed is not limited to the upper part of the storage portion 20a, and may be any position where the optical paths 40a, 40b, and 40c are shielded from external light by the light shielding unit 22.

  Note that. Provided on the inner surface of the light shielding portion 22 is an antireflection function for preventing the outgoing light emitted from the light emitting portion 31 and the reflected light from the object to be measured 20 (housing portion 20a) from being reflected by the inner surface of the light shielding portion 22. Is preferred. According to this, it is possible to prevent the light that has been reflected a plurality of times inside the light shielding unit 22 from being received by the light receiving unit 32a and the light receiving unit 32b, thereby causing erroneous detection. As the antireflection function, for example, a method of coating the inner surface of the light shielding unit 22 with an antireflection film or a method of regularly arranging minute uneven portions at a pitch equal to or smaller than the wavelength of the emitted light emitted from the light emitting unit 31 is known. It has been.

  FIG. 7 shows a modification of the distance measuring device 10 of the present embodiment. In the present embodiment, the storage portion 20a of the object to be measured 20 is folded and stored, and the distance measuring sensor 30 is shielded so that the light emitting unit 31 can emit light to the folded surface of the storage portion 20a. It is provided on the side surface of the portion 22. The light paths 40a, 40b and 40c from the light emitting unit 31 to the storage part 20a, from the storage part 20a to the light receiving part 32a, and from the storage part 20a to the light receiving part 32b are shielded from external light by the light shielding part 22.

  Even in such an aspect, it is possible to detect the length of the developed portion 20b of the measurement object 20 based on the distance between the light emitting unit 31 and the storage portion 20a. Therefore, since it is not necessary to directly measure the length of the developed portion 20b, the length of the developed portion 20b can be detected without providing the optical path 40a from the light emitting unit 31 to the device under test 20 so as to cross the outside light. Further, the light shielding unit 22 can suppress noise due to external light and prevent erroneous detection.

  Such a distance measuring device 10 can be used for a blind device provided in a window of a building.

  FIG. 8 is a cross-sectional view when the distance measuring device 10 of the present embodiment is applied to a sunroof shade device 11 for a vehicle. As shown in FIG. 8, a skylight 51 for taking in external light is provided in the ceiling portion of the vehicle body 50, and the sunroof shade device 11 is provided inside the skylight 51. By pulling out the developed portion 20 b of the DUT 20, the developed portion 20 b can be used as a screen to block external light incident from the skylight 51. Further, by storing the DUT 20, external light can be taken from the skylight 51.

  In the sunroof shade device 11 for a vehicle, the unfolded portion 20b is unfolded and stored by a motor drive. When the operator inputs a sunroof shade open / close switch, the object to be measured 20 is unfolded or stored. The object to be measured 20 is a flexible sheet-like material, and a guide (not shown) is provided in the development direction of the development part 20b in order to prevent the development part 20b from being bent. Stored. In addition, even if the to-be-measured object 20 is developed and stored by a method in which the take-up shaft 21 and the light shielding portion 22 are fixed and the developed portion 20b is opened and closed, the end of the developed portion 20b is fixed and the take-up shaft is fixed. 21 and the light shielding part 22 may be moved to open and close the developed part 20b.

  In the sunroof shade device 11, the opening and closing of the deployment portion 20b can be detected from the number of rotations of the motor. However, even if the motor is rotating, the gear of the driving unit for winding the sunshade breaks down and causes the idle rotation. May end up. In this case, there is a problem that erroneous information that the expanded portion 20b is closed is output regardless of the open state.

  Since the distance measuring device 10 of the present embodiment is applied to the sunroof shade device 11 for a vehicle, and the opening / closing of the expanded portion 20b can be detected by the distance measuring sensor 30, the expanded portion even if the gear of the drive unit breaks down. The opening / closing of 20b can be reliably detected. Then, based on the information of the distance measuring device 10, information appropriate for driving the motor can be output, and the operator can be alerted.

  Further, even when the distance measuring device 10 is used for the sunroof shade device 11, the developed portion of the object to be measured 20 developed by measuring the distance between the light emitting portion 31 of the distance measuring sensor 30 and the storage portion 20a. Since the length of 20b is detected, there is no need to directly measure the expanded portion 20b. Therefore, the length of the developed portion 20b can be detected without providing the optical path 40a from the light emitting unit 31 to the DUT 20 so as to cross the external light incident from the skylight 51. Further, since the distance from the light emitting part 31 to the storage part 20a is measured, the light paths 40a, 40b, and 40c from the light emitting part 31 to the storage part 20a and from the storage part 20a to the light receiving part 32a and the light receiving part 32b are shielded. The portion 22 can be provided to easily shield the light. Therefore, it is possible to prevent erroneous detection by suppressing noise due to external light.

  In FIG. 8, the storage portion 20a, the distance measuring sensor 30, and the light shielding portion 22 are illustrated on the ceiling of the vehicle body 50 for the sake of explanation, but in actuality, the design of the interior of the vehicle 50 is taken into consideration. It is also possible to accommodate the light-shielding part 22 between the ceiling outer plate and the top plate in the vehicle. In this case, the outer plate on the ceiling of the vehicle body 50 and the top plate in the vehicle are used as the light shielding unit 22, and the optical path 40a from the light emitting unit 31 to the housing part 20a and from the housing part 20a to the light receiving unit 32a and the light receiving unit 32b, 40b and 40c can be shielded from external light.

DESCRIPTION OF SYMBOLS 10 Distance measuring device 11 Sunroof shade device 20 Object to be measured 20a Storage part 20b Deployment part 21 Winding shaft 22 Light shielding part 30 Distance sensor 31 Light emitting part 32 Light receiving part 32a, 32b Light receiving part 33 Substrate 34 Case 35 Sealing resin 40a 40b, 40c Optical path

Claims (5)

A light emitting unit for emitting outgoing light to the device under test;
A light receiving unit that receives reflected light reflected by the object to be measured;
A light shielding portion for shielding external light,
The distance measuring device, wherein the light shielding unit shields an optical path from the light emitting unit to the object to be measured and an optical path from the object to be measured to the light receiving unit from outside light. An object to be stored and deployed; and
A light emitting unit that emits outgoing light to a housing portion housed in the light shielding portion of the object to be measured;
A light receiving portion that receives the reflected light reflected by the storage portion,
A light-shielding part that shields the optical path from the light-emitting part to the storage part and from the storage part to the light-receiving part from outside light,
A distance measuring device that detects a length of an unfolded portion of the object to be measured that is unshielded by the light shielding portion based on a distance between the light emitting portion and the storage portion. .   The distance measuring device according to claim 2, wherein the storage portion is formed in a roll shape by winding the object to be measured.   4. The distance measuring apparatus according to claim 1, wherein the optical path is provided in a space formed by the light shielding unit and the object to be measured. 5. The distance measuring device according to any one of claims 1 to 4, wherein an antireflection function is provided on an inner surface of the light shielding portion.

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