JP5449419B2 - Anti-fog window unit - Google Patents

Description

  The technique regarding the translucent material attached with respect to the opening opened to the housing | casing is disclosed below.

  For example, at a toll gate on a toll road, a vehicle detection device as disclosed in Patent Document 1 using a photoelectric sensor is installed to detect a passing vehicle. The vehicle detection device may be installed independently as in Patent Document 1, or in an ETC lane or the like, it is installed as an integrated type housed in a case of a traffic blocking device that rotates a blocking bar. In some cases. As described in Patent Document 1, such a vehicle detection device includes a light emitting side housing and a light receiving side housing that are installed to face each other across a traffic path through which the vehicle passes (patent). The light emitting unit having one or more light emitting elements is accommodated in the light emitting side housing, and the light receiving unit having a light receiving element corresponding to the light emitting element is accommodated in the light receiving side housing. .

  Both cases on the issue side and the light receiving side are provided with a light transmission window for transmitting light emitted by the light emitting unit corresponding to the installation height of the light emitting element and the light receiving element. In the case of the vehicle detection device disclosed in Patent Document 1, a simple opening is provided in the housing, and rainwater or the like enters the light emitting surface and the light receiving surface of the light emitting unit and the light receiving unit. Therefore, Patent Document 1 discloses a cover that is attached to both units for the purpose of preventing water droplet adhesion on the light emitting surface and the light receiving surface.

JP 2011-233472 A

  For the above vehicle detection devices installed on toll roads in wind and snow areas such as Tohoku and Hokkaido, obstacles due to snow falling on the side are a problem. In other words, in the vehicle detection devices installed in these areas, when snow falls, snow is strongly blown to the light emitting and receiving unit through the transparent window of the housing, which is a simple opening. It adheres and the translucency is inhibited. In order to prevent snow from blowing, glass or plastic light-transmitting material can be fitted in the light-transmitting window to make the case sealed, but this time, due to the temperature difference between the inside and outside of the case during cold weather The problem is that the translucent material becomes cloudy due to condensation, or snow adheres to the translucent material, which impairs the translucency of the translucent window.

  In view of the above background, a vehicle detection device using a photoelectric sensor that uses light (visible light, invisible light) needs some contrivance in consideration of anti-fogging during cold and snow prevention during snowfall.

Proposed for this problem is an anti-fogging window unit attached to the opening provided in the housing,
A heat conductive frame having a through hole; a translucent material held by the frame so as to close the through hole; and a heater for heating the frame.
When the frame is fixed to the casing, the translucent material faces the opening of the casing, and heat of the frame heated by the heater is transmitted to the translucent material. It is.

  The anti-fogging window unit according to the above proposal has an anti-fogging function and prevents condensation because the translucent material held by the frame is heated by the heater. Further, by setting the heating temperature by the heater high, it is possible to obtain a snow melting effect and to prevent snow. Accordingly, a decrease in translucency is suppressed during cold weather or wind and snow, and the sensor function is not impaired.

Schematic which shows the example of installation of a vehicle detection apparatus. The (A) front view, (B) rear view, and (C) side view which show embodiment of an anti-fogging window unit. The figure which shows the example which attached the anti-fog window unit which concerns on embodiment in the housing | casing of a vehicle detection apparatus. The figure explaining the housing | casing attachment state of the anti-fog window unit which concerns on embodiment. The circuit diagram which shows the controller of the anti-fog window unit which concerns on embodiment. Schematic which shows the example which applied the anti-fog window unit to the surveillance camera. Schematic which shows the example which applied the anti-fog window unit to the sensor for crime prevention.

  FIG. 1 shows an installation example of a vehicle detection device to which an anti-fogging window unit is attached as an example. A vehicle detection device using a photoelectric sensor that is installed in a toll gate on a toll road and detects the passage of a vehicle may be independently installed as a single vehicle detection device as shown in FIG. In some cases, as shown in FIG. 1B, it may be installed as an integrated type housed in a casing of a traffic blocking device that rotates the blocking bar.

  The vehicle detection device of FIG. 1A includes a light emitting side housing 1 and a light receiving side housing 2 that are erected on both sides of a traffic path. The housings 1 and 2 are both metal boxes, and the light emitting side housing 1 houses the light emitting unit of the photoelectric sensor, and the light receiving side housing 2 houses the light receiving unit of the photoelectric sensor. The light emitting unit and the light receiving unit in FIG. 1A are configured to have three sets of light emitting elements and light receiving elements in the vertical direction and perform detection at different heights. Correspondingly, three openings 1a to 1c and 2a to 2c arranged in the vertical direction are provided on each side surface of the housings 1 and 2 facing the passageway so that the light beam from the light emitting unit reaches the light receiving unit. The antifogging window unit 10 shown in FIG. 2 and subsequent figures is attached so as to face the openings 1a to c and 2a to c.

  On the other hand, in the vehicle detection device of FIG. 1B, a light emitting unit of a photoelectric sensor is housed in a housing 3 of a traffic blocking device erected on one side of a traffic path, and the photoelectric sensor receives light on the opposite side across the traffic path. A casing 4 containing the unit is erected and configured. Each of the casings 3 and 4 has a metal box shape, and openings 3a and 4a corresponding to the light emitting elements and the light receiving elements of the light emitting unit and the light receiving unit are formed on the respective side surfaces facing the passage. The defogging window unit 10 shown in FIG. 2 and subsequent figures is attached to the openings 3 a and 4 a, respectively, and a set of light emitting elements and light receiving elements performs detection operation through the defogging window unit 10.

In FIG. 2, the external appearance of the anti-fogging window unit 10 is shown. FIG. 2A is a front view facing the outside of the casings 1, 2, 3, and 4, FIG. 2B is a rear view facing the inside of the casings 1, 2, 3, and 4, and FIG. 2C is a side view when viewed from above. It is.
The illustrated anti-fogging window unit 10 includes a frame 11, a translucent material 12, and a heater 13.

  The frame 11 is a substantially square metal plate and has thermal conductivity, and a circular through-hole 11a for allowing the light beam of the photoelectric sensor to pass therethrough is formed in the approximate center thereof. On the front surface (outer surface) of the frame 11, a flange portion 11b surrounding the through hole 11a is provided upright around the through hole 11a. A step portion 11c is formed around the flange portion 11b so as to surround the flange portion 11b. In the frame 11 of the present embodiment, screw holes 11d for fixing the frame 11 to the casings 1, 2, 3, and 4 are formed at equal intervals, further outward from the step portion 11c.

  In the case of this embodiment, the translucent material 12 is made of transparent glass or resin, and is formed in a disk shape that fits on the inner periphery of the flange portion 11 b provided on the frame 11. The translucent material 12 fitted inside the flange portion 11b is held so that its outer peripheral surface is in contact with the inner peripheral surface of the flange portion 11b on the entire circumference and is surrounded by the flange portion 11b so as not to move. It is held by the frame 11 so as to close the through hole 11a. The photoelectric sensors housed in the housings 1, 2, 3, and 4 can perform a detection operation through the light transmissive material 12. A heat conductive adhesive can also be used to fix the translucent material 12 in the flange portion 11b.

  The heater 13 is configured by using, for example, a metal clad resistor, and generates heat by being controlled by the controller 14. Two heaters 13 according to the present embodiment are used, and are fixed by screwing, bonding, or the like so that the entire side surface is in contact with a portion of the back surface (inner surface) of the frame 11 that avoids the through hole 11a. Thereby, the heater 13 heats the frame 11, and the heat of the frame 11 heated by the heater 13 is transmitted to the translucent material 12.

  An anti-fogging window temperature sensor 15 is disposed on the back surface of the frame 11, the temperature of the frame 11 heated by the heater 13 is measured, and the measured voltage is input to the controller 14. Further, a housing temperature sensor 16 is disposed at a predetermined position on the inner side surface of the housings 1, 2, 3, and 4, and a measurement voltage of the housing temperature sensor 16 is transmitted to the controller 14 as a housing temperature measurement value. Entered.

  FIG. 3 shows the state when the defogging window unit 10 is attached to the sensor openings 1a to c, 2a to c, 3a, and 4a of the housings 1, 2, 3, and 4 when viewed from the outside (front side). ing. 4A is a side view of the anti-fogging window unit 10 seen from the cross section along line AA in FIG. 3, and FIG. 4B is a cross section of the anti-fogging window unit 10 seen from the section along line BB in FIG. The figure is shown.

  Bolt holes corresponding to screw holes 11d formed in the frame 11 of the anti-fogging window unit 10 are formed around the openings 1a to c, 2a to c, 3a, and 4a in the housings 1, 2, 3, and 4. The frame 11 is fixed to the housings 1, 2, 3, and 4 by screwing the bolts 17 into the screw holes 11 d through the bolt holes. When the frame 11 is fixed by the bolt 17, the translucent material 12 faces the openings 1a to c, 2a to c, 3a, and 4a. That is, when the frame 11 is fixed to the casings 1, 2, 3, and 4, the flange portion 11b is inserted into the openings 1a to c, 2a to c, 3a, and 4a, and the translucent material 12 in the flange portion 11b is inserted. Cover the openings 1a to c, 2a to c, 3a and 4a. Further, in the embodiment shown in FIGS. 3 and 4, a sealing material 11e made of rubber or the like is fitted on the outer periphery of the flange portion 11b, and the sealing material 11e surrounding the flange portion 11b is almost airtight and liquid-tight. A state is formed. The light emitting units and the light receiving elements of the light receiving units and the light receiving units housed in the casings 1, 2, 3 and 4 emit and receive light through the translucent material 12 facing the openings 1a to c, 2a to c, 3a and 4a. It can be performed.

  Since the casing 11, 2, 3, and 4 do not directly contact the flange portion 11 b by surrounding the flange portion 11 b and the sealing material 11 e is fitted, when heat is transmitted from the frame 11 to the translucent material 12 In addition, the path through which the heat of the frame 11 escapes to the housings 1, 2, 3, and 4 is suppressed. Therefore, the heat of the frame 11 due to the heating of the heater 13 is efficiently transmitted to the translucent material 12, and the translucent material 12 can be warmed to about 100 ° C.

  In the example of FIG. 3, a fan 20 that circulates air is disposed in the housings 1, 2, 3, and 4 above the position where the anti-fogging window unit 10 is attached. Since the temperature of the anti-fogging window unit 10 of this embodiment can be raised to 70 ° C. or more by the heater 13, the air heated by this radiant heat is blown by the fan 20 and the casings 1, 2, 3, 4. If it spreads in, it can aim at temperature rising in the housing | casing 1,2,3,4. Thereby, the effect | action which prevents dew condensation other than the translucent material 12 can be acquired.

  When the flange portion 11b is inserted into the openings 1a to c, 2a to c, 3a, and 4a by attaching the anti-fogging window unit 10, the step portion 11c formed around the flange portion 11b is replaced with the casing 1, It abuts on the peripheral edges of the openings 2, 3 and 4. The stepped portion 11c is preferably in the illustrated form continuously provided on the outer peripheral surface of the flange portion 11b. However, the stepped portion 11c may have a protruding piece shape formed away from the flange portion 11b. A gap S is formed between the fixed frame 11 and the casings 1, 2, 3, 4 by the stepped portion 11 c contacting the inner side surfaces of the casings 1, 2, 3, 4. Due to the gap S, the contact area between the frame 11 and the casings 1, 2, 3, 4 is limited to the stepped portion 11 c and the gap S functions as a heat insulating layer. , 4 is suppressed heat escape.

A circuit example of the controller 14 for driving the heater 13 is shown in FIG.
First, the output voltage of the casing temperature sensor 16 that measures the temperature of the casings 1, 2, 3, and 4 is input to the first comparator 14a and compared with a predetermined reference voltage. As an example, the reference voltage compared by the first comparator 14a corresponds to a voltage output from the sensor 16 when the housing temperature is 15 ° C. Therefore, in the first comparator 14a, it is determined whether the temperature of the casings 1, 2, 3, and 4 is 15 ° C. or lower or exceeds 15 ° C. The reference voltage may be set as appropriate according to the installation environment of the casings 1, 2, 3, and 4.

  The comparison result of the first comparator 14a is provided to the switch 14b, and the switch 14b is switched according to the comparison result. The switch 14b selects and inputs at least two reference voltages of a high temperature setting reference voltage and a low temperature setting reference voltage having different values according to the comparison result of the first comparator 14a to the second comparator 14c. The output voltage of the anti-fogging window temperature sensor 15 is compared with the reference voltage by the second comparator 14c. As an example, the high temperature setting reference voltage selected by the switch 14b is a reference value for setting the temperature of the frame 11 to 70 ° C. to 90 ° C., and the low temperature setting reference voltage sets the temperature of the frame 11 to 50 ° C. to 70 ° C. It is a reference value for setting to ° C. This reference voltage is appropriately adjusted according to the characteristics of the heater 13 and set.

  The comparison result of the second comparator 14c is input to the driver 14d, and the driver 14d controls the current flowing to each heater 13 according to the comparison result.

  Under the control of the controller 14, a high temperature setting reference voltage is set when the casing temperature is 15 ° C. or lower, and the anti-fogging window unit 10 is heated to a relatively high temperature of 70 ° C. or higher. On the other hand, when the casing temperature exceeds 15 ° C., the low temperature setting reference voltage is set, and the anti-fogging window unit 10 is heated to a relatively low temperature of 70 ° C. or less. When the temperature is cold or windy and snowy, the set temperature can be raised to increase the antifogging and snowproof effect, while when the outside air temperature is relatively high, the set temperature can be lowered to enter the energy saving mode.

  In the defogging window unit 10 according to the present embodiment, the frame 11 is heated to 70 ° C. or more by the heater 13 during cold weather or wind and snow, and this heat is transmitted to the translucent material 12 and around the translucent material 12. The casings 1, 2, 3, and 4 are also warmed by the radiant heat. Thereby, anti-fogging is achieved in the translucent material 12 and its periphery, and the effect of melting snow can be obtained. Accordingly, a decrease in translucency of the translucent material 12 is suppressed during cold weather, wind and snow, and the sensor function is not impaired.

6 and 7 show an example in which the anti-fogging window unit 10 is applied to a surveillance camera and an example in which the anti-fogging window unit 10 is applied to a gate pillar incorporating a security sensor.
In the example of FIG. 6, the defogging window unit 10 having the structure according to the above embodiment is attached to the opening provided in the housing 30 of the surveillance camera (the fan 20 can be used in combination). An image pickup device and an optical system are accommodated inside the anti-fogging window unit 10, and an image is taken through the anti-fogging window unit 10. As described above, the anti-fogging and snow melting functions of the anti-fogging window unit 10 can be obtained, so that a decrease in translucency is suppressed during cold weather or wind and snow, and the camera function is maintained.
In the example of FIG. 7, a photoelectric sensor such as an infrared ray is accommodated in a casing 40 that constitutes a gate pole, and the structure according to the above embodiment with respect to the opening of the casing 40 that forms the optical path OP of the photoelectric sensor. The anti-fogging window unit 10 is attached (the fan 20 can be used together). As described above, the antifogging window unit 10 provides antifogging and snowmelting effects, so that a decrease in translucency of the sensor light is suppressed during cold weather or snowstorm, and the sensor function is maintained.

1, 2, 3, 4 Housings 1a, 1b, 1c, 2a, 2b, 2c, 3a, 4a Opening 10 Anti-fog window unit 11 Frame 11a Through hole 11b Flange part 11c Step part 11d Screw hole 11e Sealing material 12 Through Light material 13 Heater 14 Controller 15 Anti-fogging window temperature sensor 16 Housing temperature sensor 17 Bolt 20 Fan S Gap

Claims (6)

An anti-fogging window unit attached to an opening provided in a housing,
A thermally conductive frame having a through hole, and the through hole translucent held by the frame so as to cover the material, and a heater for heating the frame, only including,
When the frame is fixed to the casing, the translucent material faces the opening of the casing, and the heat of the frame heated by the heater is transmitted to the translucent material ,
A first comparator that compares the output of the sensor that measures the temperature of the housing with a predetermined reference value, and a high-temperature setting reference value and a low-temperature setting reference value that are different depending on the output of the first comparator. A switch to be selected; a second comparator that compares a reference value selected by the switch with an output of a sensor that measures the temperature of the frame; and a driver that drives the heater according to the output of the second comparator. Controlled by a controller composed of
Anti-fog window unit. The frame has a flange portion erected around the through hole,
The translucent material is surrounded and held by the flange portion,
The anti-fogging window unit according to claim 1, wherein when the frame is fixed to the casing, the light transmitting member faces the opening by inserting the flange portion into the opening of the casing. The frame has a step portion formed around the flange portion,
When the flange portion is inserted into the opening of the housing, the stepped portion comes into contact with the peripheral edge of the opening of the housing, and a gap is formed between the frame fixed to the housing and the housing. The defogging window unit according to claim 2.   The anti-fogging window unit according to claim 2 or 3, further comprising a sealing material surrounding the flange portion of the frame. A photoelectric sensor configured to include a casing to which the anti-fogging window unit according to any one of claims 1 to 4 is attached, and the photoelectric sensor accommodated in the casing passes through the light-transmitting material of the anti-fogging window unit. A vehicle detection device that performs a detection operation. The vehicle detection device according to claim 5 , wherein a fan is installed in the housing above the position where the anti-fogging window unit is attached.

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