JP6440095B2 - Optical scanning type object detection device - Google Patents

Description

  The present invention relates to an optical scanning type object detection apparatus that detects an object by scanning and projecting a laser beam or the like.

  In recent years, in order to detect obstacles in the forward direction of travel in fields such as automobiles and flying objects, laser light is emitted while scanning, and reflected light reflected by the object is received and emitted and received. Based on this time relationship, a laser scanning type measuring machine that acquires information on obstacles has been developed and put into practical use.

  In a general laser scanning type measuring machine, a light projecting system is composed of a laser diode and a collimator, a light receiving system is composed of a light receiving lens (or mirror) and a light detecting element such as a photodiode, and the light projecting system. A reflecting mirror having a reflecting surface is disposed between the light receiving system and the light receiving system. In such a laser scanning type measuring machine, the light emitted from the light projecting system is scanned and projected by the rotation of the reflecting mirror, so that the object is measured in a wide range two-dimensionally rather than at a single point. There is a merit that you can.

  In addition to the above-mentioned obstacle detection of moving objects, the laser scanning type measuring machine is installed under the eaves of buildings to detect suspicious people, or it is mounted on helicopters and aircraft to acquire topographic information from the sky It can also be applied to topographical survey applications, and it can also be applied to gas detection applications that measure gas concentrations in the atmosphere. However, in many of the above-mentioned applications, the laser scanning type measuring machine is assumed to be used outdoors. Therefore, in use, a housing for protecting each element such as a light emitting system and a light receiving system from the external environment is provided. It is desirable to provide a transparent window portion in the housing so as not to block the laser light emitted from the housing. However, for example, when the temperature inside the case rises due to the heat generated by each element when the outside air temperature is low, and the temperature difference between the inside and outside of the case becomes large, condensation may occur inside the window part through which the laser light passes, There is a problem that the detection performance is deteriorated due to the fogging of the window due to such dew condensation or water droplets adhering thereto, the attenuation of the amount of transmitted laser light and the directivity of the luminous flux deteriorate. Therefore, a device for preventing the occurrence of condensation at the window through which the laser beam is transmitted is necessary.

Patent No. 3209667 specification Patent No. 4869427

  In Patent Document 1, in order to suppress the condensation of the window (transmission panel) that attenuates the amount of laser light and lowers the object detection performance, an air layer is formed between two transmissive panels arranged in a stacked manner, and the heat insulation effect A technique for ensuring the above is disclosed. However, in this conventional technique, since two transmissive panels are used, the laser light is forced to pass through the transmissive panel a total of four times by projecting and receiving light, so that the amount of laser light depends on the light transmittance of the panel. There is a problem that the light utilization efficiency is lowered due to a large attenuation. For example, assuming that the transmittance of one transmissive panel is 90%, the light utilization efficiency when reaching the light receiving system is 81% in the configuration with one transmissive panel, whereas in the configuration with two transmissive panels, The light utilization efficiency is reduced to 66%. In addition, since two transmissive panels must be fixed, there is a problem that the structure becomes heavy and complicated.

  On the other hand, in Patent Document 2, in order to capture an image from the sky, in a camera stabilizer including a sealed casing and a camera housed in the casing, air (hot air) including circuit exhaust heat is supplied by a fan. A technique for suppressing condensation by heating a window part by forcibly sending is disclosed. In the case of this conventional technology, it is necessary to secure a dedicated fan for sending hot air to the window and a flow path for sending hot air, which complicates the structure and requires power for the fan to save energy. There is no problem.

  The present invention has been made in view of the above circumstances, and provides an optical scanning type object detection device capable of ensuring sufficient object detection performance by suppressing dew condensation in a window portion while having a simple configuration. With the goal.

The present invention
A light source that emits a luminous flux;
A rotating mirror body having a mirror surface that rotates about a rotation axis;
A light receiving portion for receiving a light beam;
A window portion having light transmittance is provided, and the housing includes the light source, the rotating mirror body, and the light receiving portion.
The light beam emitted from the light source is reflected by the rotating mirror surface, scanned and projected to the outside of the housing through the window portion,
A part of the light beam reflected by the object out of the scanned and projected light beam is reflected by the mirror surface inside the housing through the window and then received by the light receiving unit. An optical scanning type object detection device comprising:
When the heat transfer length / (the thermal conductivity of the material × the cross-sectional area orthogonal to the heat transfer direction) is the thermal resistance, the heat transfer length and the cross-sectional area orthogonal to the heat transfer direction are one each. Condensation induction part having a predetermined shape that is a value is provided,
Wherein a part other than the window portion of the housing, the condensation-induced part having a thermal resistance smaller thermal resistance of the window portion is disposed so as to contact the inside and outside of the housing,
The dew condensation inducing section is arranged on the surface of the casing that intersects with the extension line of the rotating shaft, the temperature of which decreases when an air flow is generated in the casing by the rotation of the rotating mirror body. is there.

  ADVANTAGE OF THE INVENTION According to this invention, although it is a simple structure, the optical scanning type target object detection apparatus which can suppress the dew condensation of a window part and can ensure sufficient target object detection performance can be provided.

It is the schematic which shows the state which mounted the laser radar as an optical scanning type target object detection apparatus concerning this Embodiment in a vehicle. It is a perspective view which shows the principal part except the housing | casing of the laser radar LR concerning 1st Embodiment. (A) is sectional drawing which cut | disconnects and shows the laser radar concerning 1st Embodiment by the surface containing the rotating shaft RO. (B) is sectional drawing which shows the other example of the laser radar concerning 1st Embodiment. It is a figure which shows the state which scans the inside of the detection range G of the laser radar LR with the laser spot light SB (it shows by hatching) radiate | emitted according to rotation of the mirror unit MU. It is a temperature distribution figure which shows the simulation result which the present inventors performed. FIG. 4 is a cross-sectional view similar to FIG. 3 of a laser radar LR according to a second embodiment. It is sectional drawing similar to FIG. 6 of the laser radar LR concerning 3rd Embodiment. It is sectional drawing similar to FIG. 7 of the laser radar LR concerning 4th Embodiment. It is sectional drawing similar to FIG. 7 of the laser radar LR concerning 5th Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In this specification, the thermal resistance is “heat transfer length / (material thermal conductivity × cross-sectional area perpendicular to the heat transfer direction)”. FIG. 1 is a schematic view showing a state in which a laser radar as an optical scanning type object detection device according to the present embodiment is mounted on a vehicle. Although the laser radar LR of the present embodiment is provided behind the front grille 1b of the vehicle 1, it may be arranged outside the vehicle (such as the upper end of the front window 1a).

(First embodiment)
FIG. 2 is a perspective view showing a main part excluding the casing of the laser radar LR according to the first embodiment. However, the shape and length of the components may be different from actual ones. The laser radar LR is, for example, a pulsed semiconductor laser (light source) LD that emits a laser beam, a collimator lens CL that converts divergent light from the semiconductor laser LD into parallel light, and a laser that is collimated by the collimator lens CL. A mirror unit (rotating mirror body) MU that scans and projects light toward the object OBJ side (FIG. 1) by a rotating mirror surface and reflects reflected light from the scanned object OBJ; It has a lens LS that collects the reflected light from the object OBJ reflected by the mirror unit MU, and a photodiode (light receiving unit) PD that receives the light collected by the lens LS.

  The mirror unit MU has a shape in which two quadrangular pyramids are joined together in opposite directions, that is, has four pairs of mirror surfaces M1 and M2 that are inclined in a direction facing each other. The mirror surfaces M1 and M2 are preferably formed by depositing a reflective film on the surface of a resin material (for example, PC) in the shape of a mirror unit.

  The semiconductor laser LD and the collimating lens CL constitute a light projecting system LPS, and the lens LS and the photodiode PD constitute a light receiving system RPS. The optical axes of the light projecting system LPS and the light receiving system RPS are orthogonal to the rotation axis RO of the mirror unit MU.

  FIG. 3A is a cross-sectional view showing the laser radar cut along a plane including the rotation axis RO of the mirror unit MU, but the thickness of the reflection film constituting the mirror surfaces M1 and M2 is exaggerated. ing. The box-shaped casing CS is made of resin, and includes an upper wall CSa, a lower wall CSb facing the upper wall CSa, and a side wall CSc connecting the upper wall CSa and the lower wall CSb. An opening CSd is formed in a part of the side wall CSc, and a transparent plate TR as a window portion is attached to the opening CSd. The transparent plate TR preferably formed of acrylic, glass, PC, or the like has one surface in contact with the inside of the housing CS and the other surface in contact with the outside of the housing CS. In this example, the lower wall CSb is an attachment surface for attaching to another member.

  In the upper wall CSa of the casing CS, an opening CSe is formed at a position intersecting with the rotation axis RO, and a metal plate MP as a condensation inducing portion is attached to the opening CSe, and one surface thereof is the casing. The other surface is in contact with the outside of the housing CS. Here, the thermal resistance of the metal plate MP is made smaller than the thermal resistance of the transparent plate TR as the window portion. The metal plate MP is preferably made of a material that does not rust, such as aluminum or stainless steel. When the upper wall CSa is the mounting surface, the metal plate MP may be installed on the lower wall CSb or the side wall CSc. When the side wall CSc is the mounting surface, the upper wall CSa, the lower wall CSb, or the transparent plate TR. You may install in the side wall CSc of the side. Further, the dew condensation inducing part can be formed of a material other than metal, for example, a resin together with a housing. In this case, it is necessary to make the thermal resistance smaller than that of the window portion. Specifically, in order to reduce the thermal resistance, according to the definition of the thermal resistance described above, to make the plate thickness thinner than the window and other parts, use a material having a larger thermal conductivity than the window, It is conceivable to make the area larger than the window, and either of these may be used together.

  FIG. 3B is a cross-sectional view showing an example in which the dew condensation inducing part is formed of resin together with the housing. In the example shown in FIG. 3B, a part CSa 'of the upper wall CSa of the casing CS is formed thin to make it smaller than the thermal resistance of the window.

  In the present embodiment, as shown in FIG. 3, since the mirror surfaces M1 and M2 are inclined so as to face each other, between the mirror surface M1 facing the metal plate MP in the rotation axis RO direction and the metal plate MP. Therefore, the mirror surface M2 and the mirror unit MU main body are arranged. Further, the mirror surface M2 does not face the metal plate MP in the direction of the rotation axis RO. Here, “the mirror surface M1 faces the metal plate MP in the direction of the rotation axis RO” means that the mirror surface M1 in the direction of the rotation axis is on the side where the normal line of the mirror surface M1 faces (upward in FIG. 3). Means that at least a part of the projected image overlaps the metal plate MP.

  The mirror unit MU is connected to the shaft MTa of the motor MT and is driven to rotate. The housing CS houses a mirror unit MU, a light projecting system LPS, a light receiving system RPS, a motor MT, and other circuit boards (not shown).

  Next, the object detection operation of the laser radar LR will be described. 2 and 3, the divergent light emitted intermittently in a pulse form from the semiconductor laser LD is converted into a parallel light beam by the collimator lens CL, and is incident on the first mirror surface M1 of the rotating mirror unit MU, where After being reflected and further reflected by the second mirror surface M2, it passes through the transparent plate TR and is scanned and projected as a laser spot light having, for example, a vertically long rectangular section on the external object OBJ side.

  FIG. 4 is a diagram showing a state in which the detection range G of the laser radar LR is scanned with the emitted laser spot light SB (shown by hatching) according to the rotation of the mirror unit MU. In the combination of the first mirror surface M1 and the second mirror surface M2 of the mirror unit MU, the crossing angles are different. The laser light is sequentially reflected by the rotating first mirror surface M1 and second mirror surface M2. First, the laser light reflected by the first pair of the first mirror surface M1 and the second mirror surface M2 moves from the left to the right in the horizontal direction in the uppermost region Ln1 of the detection range G according to the rotation of the mirror unit MU. Is scanned. Next, the laser light reflected by the second pair of the first mirror surface M1 and the second mirror surface M2 is left in the horizontal direction in the second region Ln2 from the top of the detection range G according to the rotation of the mirror unit MU. To the right. Next, the laser light reflected by the third pair of the first mirror surface M1 and the second mirror surface M2 is left in the third region Ln3 from the top of the detection range G in the horizontal direction according to the rotation of the mirror unit MU. To the right. Next, the laser light reflected by the fourth pair of the first mirror surface M1 and the second mirror surface moves the lowermost region Ln4 of the detection range G from the left to the right in the horizontal direction according to the rotation of the mirror unit MU. Is scanned. Thereby, one scanning of the entire detection range G is completed. If the first pair of the first mirror surface M1 and the second mirror surface M2 return after one rotation of the mirror unit MU, the region from the uppermost region Ln1 of the detection range G to the lowermost region Ln4 again. Repeat the scan.

  2 and 3, a part of the laser beam reflected by the object OBJ out of the scanned light beam is transmitted again through the transparent plate TR and is incident on the second mirror surface M2 of the mirror unit MU in the housing CS. Incident, reflected here, and further reflected by the first mirror surface M1, collected by the lens LS, and detected by the light receiving surface of the photodiode PD. Accordingly, the object OBJ can be detected in the entire region within the detection range G.

  Here, while the light emitting system LPS, the light receiving system RPS, and the like generate heat, the temperature inside the housing CS is likely to rise. On the other hand, if the external environment of the housing CS is low, condensation occurs inside the housing CS. It tends to occur. In the present embodiment, the transparent plate TR and the metal plate MP that are in contact with the inside and the external environment of the housing CS are the conditions that cause the most condensing. However, since the thermal resistance of the metal plate MP is smaller than the thermal resistance of the transparent plate TR, condensation occurs on the metal plate MP prior to the transparent plate TR, thereby suppressing the occurrence of condensation on the transparent plate TR. .

  Here, the position where the metal plate MP is arranged will be considered. The inventors examined the heat distribution in the casing in a state where the light projecting system LPS and the light receiving system RPS are operated in the casing CS and the mirror unit MU is rotated. FIG. 5 is a temperature distribution diagram showing the results of a simulation performed by the present inventors. The position where the density of the diagram is high is the high heat part, and the position where the density of the diagram is low is the low heat part. According to FIG. 5, the vicinity of the light projecting system LPS and the light receiving system RPS is at a relatively high temperature position, both sides in the rotation axis direction of the mirror unit MU are at a relatively low temperature position, and there is a large temperature difference in the housing CS. Has occurred. This is presumably because the rotation of the mirror unit MU generates an air flow in the housing CS, which lowers the temperature on both sides of the mirror unit MU in the rotation axis direction. Therefore, the metal plate MP having a thermal resistance smaller than that of the window portion is arranged on the surface of the casing (here, the upper wall CSa) intersecting the rotation axis direction of the mirror unit MU capable of creating a low temperature condition, that is, the extension line of the rotation axis. Thus, the condensation on the metal plate MP contacting the inside and the outside of the housing CS can be further promoted, and the effect of suppressing the condensation on the transparent plate TR can be enhanced. In addition, by disposing the metal plate MP at a position away from the transparent plate TR that transmits the light beam reflected by the mirror surface M2, it is possible to avoid dew condensation caused by the metal plate MP from adhering to the transparent plate TR. In addition, a ridge etc. may be provided around the metal plate MP, and the generated dew condensation may be caused to flow away from the transparent plate TR.

  On the other hand, when the metal plate MP is installed above the mirror unit MU in the direction of gravitational acceleration, condensation generated by the metal plate MP may drop and adhere to the mirror surface. On the other hand, according to the present embodiment, when the mirror surface M1 is projected in the direction of the rotation axis RO on the side toward the normal line (upward in FIG. 3), the projection area of the mirror surface M1 and the metal plate Although the MP partially overlaps (see range B shown in FIG. 3A), the non-reflecting surface portion of the mirror unit MU is located between the mirror surface M1 and the metal plate MP. Further, the mirror surface M2 does not face the metal plate MP. Therefore, even when the condensation formed on the metal plate MP is dropped, it is blocked by the upper surface, which is the non-reflecting surface portion of the mirror unit MU, so that it does not adhere to any of the mirror surfaces M1 and M2, and its reflection performance is improved. It can be secured. In the laser radar LR of the present embodiment, there is little possibility of disposing a light projecting system LPS or a light receiving system RPS serving as a heat source in the direction of the rotation axis RO with respect to the mirror unit MU due to its structure. It is desirable that the light projecting system LPS and the light receiving system RPS be arranged at a position that does not overlap the projection area when projected in the direction of the mirror unit MU rotation axis RO, from the viewpoint of achieving a temperature balance in the housing CS. In addition, illustration is a cross section, the projection area | region of the mirror unit MU becomes a cylindrical shape, and the projection area | region of a mirror surface becomes a ring shape.

(Second Embodiment)
FIG. 6 is a cross-sectional view similar to FIG. 3 of the laser radar LR according to the second embodiment. The mirror unit MU of the present embodiment has a single substantially quadrangular pyramid shape obtained by deleting the lower half of the quadrangular pyramid from the above-described embodiment, and forms four mirror surfaces M2 on the side surface. ing. In the present embodiment, the optical axes of the light projecting system LPS and the light receiving system RPS are respectively arranged substantially parallel to the rotation axis RO. Other configurations are the same as those of the above-described embodiment. By changing the inclination angles of the four mirror surfaces M2, the screen G can be scanned two-dimensionally as shown in FIG.

  Also in the present embodiment, by arranging the metal plate MP on the surface of the casing that intersects the extended line of the rotation axis RO of the mirror unit MU, a low temperature condition that is more likely to cause dew condensation can be created near the metal plate MP. Therefore, the occurrence of condensation on the transparent plate TR can be suppressed. In addition, since the mirror surface M2 is not opposed to the metal plate MP, even when the condensation formed on the metal plate MP drops, the mirror unit MU is blocked by the upper surface and does not adhere to the mirror surface M2, and its reflection performance. Can be secured.

  By the way, in the embodiment shown in FIG. 6, it is also conceivable to arrange the metal plate MP on the lower wall CSb of the casing CS as shown by a dotted line as one of the directions of the rotation axis RO of the mirror unit MU. However, in the embodiment shown in FIG. 6, since the light projecting system LPS and the light receiving system RPS as heat sources are arranged on the lower wall CSb side with respect to the mirror surface M2, the mirror unit MU is moved by the heat generation. There is a risk of damaging the low temperature environment generated by rotation. Therefore, it can be said that it is desirable to provide the metal plate MP on the opposite side of the light projecting system LPS including the light source serving as the heat source and the light receiving system RPS including the light receiving unit, that is, the upper wall CSa with the mirror unit MU interposed therebetween.

(Third embodiment)
On the other hand, there is a case where the upper wall CSa is an attachment surface and the metal plate MP is desired to be provided on the same side as the light projecting system LPS and the light receiving system RPS with respect to the mirror unit MU. A third embodiment that satisfies this requirement will be described. FIG. 7 is a cross-sectional view similar to FIG. 6 of a laser radar LR according to the third embodiment. Only the differences from the embodiment of FIG. 6 will be described. In the present embodiment, the metal plate MP is disposed on the lower wall CSb of the casing CS. For this reason, the mirror surface M2 will face the metal plate MP. In this case, if the metal plate MP is installed on the mirror unit MU so as to be downward in the gravitational acceleration direction, the condensation generated on the metal plate MP follows the gravitational acceleration. Can be suppressed.

  Further, in the present embodiment, reflecting mirrors MR1 and MR2 are provided to bend the optical axis so as to separate the light projecting system LPS and the light receiving system RPS that are heat sources from the metal plate MP. Specifically, the light beam emitted from the light projecting system LPS is reflected by the reflecting mirror MR1, travels along the rotation axis RO, is reflected by the mirror surface M2 of the rotating mirror unit MU, and then passes through the transparent plate TR. The light is transmitted and scanned and projected to an external detection range. On the other hand, the laser beam reflected and reflected by the object OBJ among the luminous fluxes that have been scanned and projected is again transmitted through the transparent plate TR and reflected by the mirror surface M2 of the mirror unit MU in the housing CS, along the rotation axis RO. It travels, is reflected by the reflecting mirror MR2, and is detected by the light receiving system RPS.

  Thus, according to the present embodiment, when the mirror unit MU is projected in the direction of the rotation axis RO by bending the optical axis with the reflecting mirrors MR1 and MR2, the projection area (range A indicated by the dotted line) ) In addition, a light projecting system LPS (at least a semiconductor laser LD) and a light receiving system RPS (at least a photodiode PD) serving as a heat generating part are provided, so that they can be separated from the metal plate MP and rotate the mirror unit MU. Condensation can be effectively generated by installing the metal plate MP on the lower wall CSb without impairing the low temperature environment generated by the operation.

(Fourth embodiment)
FIG. 8 is a cross-sectional view similar to FIG. 7 of a laser radar LR according to the fourth embodiment. Only the differences from the embodiment of FIG. 7 will be described. In the present embodiment, the mirror unit MU is provided with only a single mirror surface M2. The motor MT performs a reciprocating rotation operation within 180 degrees. In synchronization with the reciprocating rotation of the mirror unit MU, two-dimensional scanning as shown in FIG. 4 can be performed by rotating the reflecting mirrors MR1 and MR2 stepwise using an actuator (not shown). In the present embodiment, when the lower wall CSb is an attachment surface, the metal plate MP is provided on the upper wall CSa, and when the upper wall CSa is an attachment surface, the metal plate MP is provided on the lower wall CSb. When the mirror unit MU is projected in the direction of the rotation axis RO, a light projecting system LPS and a light receiving system RPS that serve as heat generating portions are provided outside the range of the projected image (range A indicated by a dotted line).

(Fifth embodiment)
FIG. 9 is a cross-sectional view similar to FIG. 7 of a laser radar LR according to the fifth embodiment. Only the differences from the embodiment of FIG. 7 will be described. The present embodiment has a configuration in which the top and bottom are generally reversed with respect to the embodiment of FIG. However, if the top and bottom of the laser radar LR according to the embodiment of FIG. 7 is simply reversed, the condensation attached to the metal plate MP may drop and adhere to the mirror surface M2. Therefore, in the present embodiment, when the mirror surface is projected in the direction of the rotation axis RO on the side toward the normal line, the metal plate MP is provided in a place other than the projection region (range B shown in FIG. 9). I made it. That is, the projection area of the mirror surface and the metal plate MP are arranged at positions that do not overlap. However, when the mirror unit MU is projected in the direction of the rotation axis RO, it is desirable to provide the metal plate MP within the range of the projected image (range A indicated by the dotted line). Therefore, in the case of the present embodiment, the metal plate MP is provided on the upper wall CSa corresponding to the center position of the mirror unit MU. In this example, the attachment surface is the lower wall CSb.

  When the metal plate MP is installed so as to be below the gravitational acceleration direction, a concave portion MUa is formed on the upper surface of the mirror unit MU so that dew condensation can be received from the metal plate MP, In addition, it is preferable to allow condensation to escape to the lower side of the mirror unit MU via the flow path MUb communicating with the recess MUa.

  The present invention is not limited to the embodiments described in the specification, and it is apparent to those skilled in the art from the embodiments and ideas described in the present specification that other embodiments and modifications are included. It is. The description and examples are for illustrative purposes only, and the scope of the invention is indicated by the following claims. For example, all the contents of the present invention described with reference to the drawings can be applied to the embodiments, and can be applied to a flying object such as a helicopter or a security sensor installed in a building to detect a suspicious person. In the above embodiment, the semiconductor laser is used as the light source. However, the present invention is not limited to this, and it goes without saying that an LED or the like may be used as the light source.

DESCRIPTION OF SYMBOLS 1 Vehicle 1b Front grill CL Collimating lens CS Housing | casing CSa Upper wall CSa 'Part of thinned upper wall CSb Lower wall CSc Side wall CSd Opening CSe Opening G Screen LD Semiconductor laser Ln1-Ln4 Screen area LPS Projection system LR Laser radar LS lens M1 first mirror surface M2 second mirror surface (or mirror surface)
MP Metal plate OBJ Object PD Photodiode MU Mirror unit RO Rotating shaft RPS Light receiving system TR Transparent plate

Claims (8)

A light source that emits a luminous flux;
A rotating mirror body having a mirror surface that rotates about a rotation axis;
A light receiving portion for receiving a light beam;
A window portion having light transmittance is provided, and the housing includes the light source, the rotating mirror body, and the light receiving portion.
The light beam emitted from the light source is reflected by the rotating mirror surface, scanned and projected to the outside of the housing through the window portion,
A part of the light beam reflected by the object out of the scanned and projected light beam is reflected by the mirror surface inside the housing through the window and then received by the light receiving unit. An optical scanning type object detection device comprising:
When the heat transfer length / (the thermal conductivity of the material × the cross-sectional area orthogonal to the heat transfer direction) is the thermal resistance, the heat transfer length and the cross-sectional area orthogonal to the heat transfer direction are one each. Condensation induction part having a predetermined shape that is a value is provided,
Wherein a part other than the window portion of the housing, the condensation-induced part having a thermal resistance smaller thermal resistance of the window portion is disposed so as to contact the inside and outside of the housing,
The dew condensation inducing unit is an optical scanning type object disposed on the surface of the casing that intersects with an extension line of the rotating shaft, the temperature of which decreases when an air flow is generated in the casing by rotation of the rotating mirror body Object detection device. The mirror surface, when projected in the direction of the rotary shaft on the side of the normal is directed, and the projected area of the mirror surface, the object of the optical scanning according to claim 1, and the condensation inducing portion do not overlap each other Object detection device. When the mirror surface is projected in the direction of the rotation axis on the side toward which the normal line is directed, the projection area of the mirror surface and the condensation inducing part overlap each other, and the projection area and the condensation inducing part are during the optical scanning type of object detecting apparatus according to claim 1, the other members are located. The optical scanning type object detection device according to claim 1 , wherein the dew condensation inducing unit, the light source, and the light receiving unit are disposed with the rotating mirror body interposed therebetween. The optical scanning type object detection device according to any one of claims 1 to 4 , wherein the dew condensation inducing part is disposed on a surface of the housing that faces an attachment surface to another member. The optical scanning type object according to any one of claims 1 to 5 , wherein the light source and the light receiving unit are arranged at positions that do not overlap a projection region obtained by projecting the rotating mirror body in the direction of the rotation axis. Detection device. The housing is made of resin, an optical scanning of the object detecting apparatus according to any one of claims 1 to 6, wherein the condensation inducing portion is made of metal. The casing and the condensation inducing part are made of resin, and the condensation inducing part is thinner in thickness than the window part and other parts, and has a higher thermal conductivity than the window part, than the window part. The optical scanning type object detection device according to any one of claims 1 to 6 , wherein the optical scanning type object detection device has a smaller area than a thermal resistance of the window portion.