JP3774021B2 - Vehicle separator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention is used to detect the presence and the number of vehicles entering and exiting a parking lot or a toll booth using an optical scanning sensor that detects a substance over a wide range by projecting and receiving light while scanning a light beam. It relates to a vehicle separator.
[0002]
[Prior art]
Conventionally, a vehicle separator having a configuration shown in FIGS . 9 and 10 has been provided as a vehicle separator used for detecting the presence / absence and the number of vehicles entering and leaving a parking lot or a toll booth.
[0003]
This vehicle separator detects a vehicle z by scanning a light beam, and this vehicle separator includes an optical scanning sensor 1 and a regressive reflection plate 2, both of which sandwich a road d. Are arranged opposite each other.
[0004]
The optical scanning sensor 1 includes a light projecting unit 4 that emits a light beam, a light scanning unit 6 that scans the light beam from the light projecting unit 4 toward the regressive reflection plate b, and scanning by the light scanning unit 6. However, the light receiving means 8 for receiving the reflected light of the emitted light beam is provided, and the light projecting means 4 and the light receiving means 8 are arranged close to each other in parallel.
[0005]
The light projecting means 4 includes a light emitting element 10 such as an LED (light emitting diode) and a light projecting lens 12 for condensing the light from the light emitting element 10 to make the light beam as parallel as possible.
[0006]
The optical scanning unit 6 includes a galvano mirror 14 that reflects the light beam from the light projecting unit 4 and a drive mechanism 16 that swings the mirror 14 at a constant speed.
[0007]
Further, the light receiving means 8 is a light receiving lens 18 that condenses the reflected light from the retroreflector 2 or the vehicle z, and a PD (photodiode) that receives the light collected by the light receiving lens 18 and converts it into an electrical signal. ) And the like.
[0008]
On the other hand, the regressive reflection plate 2 is configured such that the light beam from the optical scanning sensor 1 causes regular reflection by arranging prisms or the like in tandem along the scanning direction of the optical beam by the optical scanning sensor 1. Yes.
[0009]
In the vehicle separator configured as described above, the light emitting element 10 of the light projecting means 4 emits a pulse light, and this light is emitted as a light beam through the light projecting lens 12, and this light beam is reflected by the galvanometer mirror 14 and is reflected back. The light is emitted toward the plate 2. In this case, since the galvano mirror 14 is always oscillated at a constant speed, the light beam reflected by the galvano mirror 14 is scanned in a fan shape while crossing the road 3 at a substantially right angle.
[0010]
Here, when the vehicle z does not exist on the road 3, each light beam emitted from the optical scanning sensor 1 is reflected as it is by the regressive reflection plate 2, and the reflected light is received by the optical scanning sensor 1. After being incident on the means 8 and condensed by the light receiving lens 18, the light is received by the light receiving element 20 and converted into an electric signal.
[0011]
On the other hand, when the vehicle z exists on the road 3, the light beam emitted from the optical scanning sensor 1 is shielded by the vehicle z in the middle of the optical scanning and is not irradiated to the return reflection plate 2. The light intensity received by the means 8 is weaker than when the vehicle z does not exist. Therefore, the presence / absence of the vehicle z is determined by comparing the amount of received light with a preset threshold value by a determination circuit (not shown).
[0012]
When determining such a vehicle z, as shown in FIG. 9 , when the vehicle z to be detected is, for example, a towing vehicle, there is a gap between the towing drive vehicle z ₁ and the towing cart z _2. They are connected by a tow bar z ₃ . Such a towing vehicle z is normally handled as a single vehicle as a whole for parking and payment of fees.
[0013]
Therefore, in order to determine such a towing vehicle z, it is necessary to detect the presence or absence of a tow bar z ₃ that connects the towing drive vehicle z ₁ and the towing cart z ₂ .
[0014]
[Problems to be solved by the invention]
Incidentally, as a light-emitting element 10 used like the above optical scanning sensor 1, conventionally, there is a LED (light emitting diode) having the structure as shown in FIG. 11.
[0015]
The LED 10 is packaged by molding a light emitting semiconductor chip 30 and each end of a pair of lead frames 32 electrically connected to the chip 30 with a molding resin 34.
[0016]
If such LED10 to emit a configuration, the light is not only from the front of the wire bonding of the semiconductor chip 30 (lower side in FIG. 11 (b)), the left and right side surface (FIG. 11 (b) ) Also emits light. The light from this side surface is reflected by the lead frame 32 and the reflected light is emitted toward the light projecting lens 12 side.
[0017]
In FIG. 12 , the light directly emitted from the front surface of the semiconductor chip 30 of the LED 10 is indicated by a solid line, and the reflected light reflected by the lead frame 32 is indicated by a broken line. In FIG. 12 , the galvanometer mirror is omitted.
[0018]
As can be seen from FIG. 12, since one focal length f ₁ of the light projecting lens 12 is set on the semiconductor chip 30 of the LED 10, not only the light directly emitted from the front surface of the semiconductor chip 30 but also the lead frame. The reflected light reflected by 32 also passes through the light projecting lens 12 and is emitted toward the return reflection plate 2.
[0019]
Therefore, the intensity distribution of light when placed for example screen s away by a distance f ₂ in the projection lens 12 is as shown in FIG. 13.
[0020]
That is, the spot light on the screen s forms an image having a width Δw affected by the reflected light from the lead frame 32 around an image having a diameter w based on light directly emitted from the front surface of the semiconductor chip 30. .
[0021]
Therefore, even when an object having a diameter w is arranged at the same position of the screen s, the light having the width Δw on both sides thereof is reflected on the recursive reflection plate 2 after being irradiated on the return reflection plate 2 without being blocked by the object. Since the received light is received by the light receiving means 8, an object having the width w cannot be detected.
[0022]
Only when an object having a diameter w + 2Δw is arranged at the position of the screen s, all the light is blocked by this object and is not irradiated on the regressive reflection plate 2, so that the object can be detected.
[0023]
As described above, in the prior art, no measures are taken to eliminate the influence of the reflected light from the lead frame 32, and therefore the minimum detection object is large.
[0024]
From the above, for example, when the light projecting means 4 including the light emitting element 10 is used in the vehicle separator, the towing drive vehicle z _{1 and the} tow cart z ₂ having a large vehicle body shape are used. Even if it can be detected, an elongated shape such as the tow bar z ₃ cannot sufficiently detect this, and the vehicle should be regarded as one vehicle as a whole. There is a disadvantage that the two units z ₁ and z ₂ are erroneously determined to be present.
[0025]
In the conventional device, when the semiconductor chip 30 and the lead frame 32 are packaged with the mold resin 34, the components 30 and 32 may be displaced from the intended mounting positions. When there is such a mounting error, when the positioning of the light projecting lens 12 with respect to the light emitting element 10 is performed with reference to the positions of the mold resin 34 and the lead frame 32, the light projecting lens 12 and the semiconductor chip 30 are used. As a result, there is a disadvantage that the optical scanning position is shifted.
[0026]
The present invention has been made paying attention to such a conventional problem, so that it is possible to generate an unexpanded spot light, reduce the minimum detection object, eliminate false detection, It is an object of the present invention to prevent the scanning position when performing optical scanning from being affected by a mold mounting error of a light emitting element.
[0027]
[Means for Solving the Problems]
The present invention employs the following configuration in order to solve the above problems.
[0028]
That is, in the invention according to claim 1, the light projecting means for emitting light, the light scanning means for scanning the light beam emitted from the light projecting means in a direction crossing the road, and the light scanning means are separated. a regressive reflection plate disposed opposite, by a change in the received light quantity of the reflected light at the light receiving hands stage comprises a receiving unit, a receiving reflected light from the regressive reflection plate of a light beam scanned by said optical scanning means In the vehicle separator for detecting a vehicle, the shape of the light beam emitted from the light projecting means is a length in a direction along the vehicle traveling direction of the road with respect to a length in a direction perpendicular to the road surface of the road. It is characterized by being longer.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 is a block diagram showing a portion of the optical scanning sensor according to an embodiment of the present invention, the same reference numerals are assigned to the portions corresponding to FIGS. 10 to 12.
[0030]
The optical scanning sensor 1 of this embodiment includes a light projecting means (light projecting device) 4, an optical scanning means 6, and a light receiving means (not shown).
[0031]
Light projecting means 4, the LED 10 ₁ as a light emitting element, consisting of the light projecting lens 12. The optical scanning unit 6 includes a galvanometer mirror 14 and a drive mechanism 16 that swings the mirror 14 at a constant speed.
[0032]
The configuration of the light receiving means (not shown) is the same as the conventional one. In addition, the optical scanning means 6 has a configuration including the galvanometer mirror 14, but can also be configured with a polygon mirror (multi-plane rotating mirror).
[0033]
The feature of this embodiment lies in the LED 10 ₁ a structure constituting the light projecting means 4.
[0034]
That is, the LED 10 _1, as shown in FIG. 2, the semiconductor chip 30 for emitting a respective end portions of the pair of lead frames 32 which are electrically connected to the chip 30 is molded by the mold resin 34 Although the packaging is the same as in the conventional case, in this embodiment, a slit 36 serving as a light limiting unit is provided on the surface of the mold resin 34 facing the semiconductor chip 30.
[0035]
Moreover, the slit hole 37 of the slit 36 has a rectangular shape so as to limit the light emission direction only in the direction parallel to the scanning direction of the light beam by the light scanning means 6. That is, when the light beam is scanned in the vertical direction by the galvanometer mirror 14, the short side of the rectangular slit hole 37 is made to coincide with the scanning direction of the light beam.
[0036]
When light is emitted to LED 10 ₁ of this configuration, the light is not only a wire bonding side of the front surface of the semiconductor chip 30 (the right side in FIG. 2), emits light from the side surface. The light from this side is reflected by the lead frame 32, but the short side of the slit hole 37 in the reflected light is shielded by the slit 36 as shown by the broken line in FIG. In addition, the light is not emitted toward the light projecting lens 12 side. On the other hand, on the long side of the slit hole 37, the reflected light from the lead frame 32 is also emitted as it is toward the light projecting lens 12.
[0037]
Therefore, the spot light p obtained by reflecting the light beam from the light projecting means 4 with the galvanometer mirror 14 has a short length b parallel to the optical scanning direction and a long length a in the direction orthogonal thereto. That is, since the width b of the spot light p is small in the optical scanning direction, the minimum detected object can be reduced. On the other hand, in the direction perpendicular to the optical scanning direction, the spot light p has a sufficiently large width a and the entire area of the spot light p is large, so that it is hardly affected by rain, snow, dust, and the like. Can be avoided.
[0038]
Further, when the semiconductor chip 30 and the lead frame 32 in a package with a molding resin 34, it is that these components 30, 32 is deviated from the desired mounting position, the alignment of the LED 10 ₁ and the light projecting lens 12 If the positions of the slits 37 of the slit 36 are used as a reference, the optical axes of the two 10 ₁ and 12 do not shift, so that there is no inconvenience that the optical scanning position shifts as in the prior art.
[0039]
FIG. 3 is a perspective view showing a state in which a vehicle separator is configured using the optical scanning sensor 1 having the configuration shown in FIGS. 1 and 2 and installed near a toll road or a parking lot toll. is there.
[0040]
In this vehicle separator, the optical scanning sensor 1 and the regressive reflection plate 2 are arranged to face each other with a road 3 therebetween.
[0041]
In the vehicle separator having this configuration, the shape of the light beam emitted from the optical scanning sensor 1 is short in the direction perpendicular to the road surface, which is the optical scanning direction, and long in the vehicle traveling direction orthogonal thereto.
[0042]
On the other hand, the diameter of the traction rod z ₃ of tractors z small, the optical scanning sensor 1, with respect to the light scanning direction, since an object has sufficient detection capability even small traction rod z ₃ where the elongated shape However, this can be detected sufficiently. Therefore, unlike the conventional case, there is no possibility of erroneous detection such that what should be regarded as one vehicle as a whole is erroneously determined that there are two vehicles z ₁ and z ₂ minutes.
[0043]
In addition, as described above, the probability of erroneous detection due to light beams being blocked by rain, snow, dust, or the like is low.
[0044]
In the above embodiment, the shape of the slit 37 of the slit 36 has been a rectangular ones, is not limited thereto but may be a oval circle if necessary.
[0045]
(Modification)
Instead of the LED 10 ₁ having the above structure, it is also possible to use those of the following configuration.
[0046]
(1) LED 10 ₂ shown in FIG. 4, slits 37 are embedded in the mold resin 34 for molding the semiconductor chip 30. Moreover, LED 10 ₃ shown in Figure 5, together with the semiconductor chip 30 is mounted directly on the circuit board 42 without using a mold resin, the slits 37 are disposed around the semiconductor chip 30.
[0047]
According to the configuration shown in FIG. 4 or FIG. 5 , the coupling efficiency of the light emitted from the LEDs 10 ₂ and 10 ₃ to the light projection lens 12 is higher than in the embodiment shown in FIG. The amount of light emitted from the increases.
[0048]
(2) LED 10 ₄ shown in FIG. 6, instead of providing the slit, the light limiting means by the lead frame 32 around the semiconductor chip 30 is embedded in the mold resin 34 is formed to have an inclined surface 33 Is configured. The LED 10 ₅ shown in FIG. 7 does not use a mold resin, and instead of providing a slit, the semiconductor chip 30 is directly mounted on the circuit board 42, and the circuit board 42 around the semiconductor chip 30 The light limiting means is formed by forming the inclined surface 43.
[0049]
According to the configuration shown in FIG. 6 or FIG. 7 , the configuration is simplified by providing no slit as compared with the embodiment shown in FIG. 2.
[0050]
(3) In the LED 10 ₆ shown in FIG. 8 , a black light shielding film 39 is formed on the lead frame 32 around the semiconductor chip 30 to constitute a light limiting means.
[0051]
According to this configuration, the shape of the slit and the lead frame and the labor of processing are not required, and the manufacturing can be easily performed.
[0052]
In each of the above embodiments, the light emitting element is an LED, but the present invention can also be applied to a light emitting element such as a laser diode.
[0053]
【The invention's effect】
The present invention has the following effects.
[0054]
In the vehicle separator according to the first aspect of the present invention, the direction perpendicular to the road surface of the road has sufficient detection capability even if the object is small, so that the tow bar having the elongated shape of the towing vehicle is sufficiently detected. be able to. Therefore, the towing vehicle can be reliably detected.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an optical scanning sensor according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of an LED constituting a light projecting device used in the optical scanning sensor of FIG.
3 is a perspective view showing a state where a vehicle separator using the optical scanning sensor configured as shown in FIG. 1 is installed on a road. FIG.
FIG. 4 is a cross-sectional view showing another embodiment of the LED constituting the light projecting device.
FIG. 5 is a cross-sectional view showing another embodiment of the LED constituting the light projecting device.
FIG. 6 is a cross-sectional view showing another embodiment of the LED constituting the light projecting device.
FIG. 7 is a cross-sectional view showing another embodiment of the LED constituting the light projecting device.
FIG. 8 is a cross-sectional view showing another embodiment of the LED constituting the light projecting device.
FIG. 9 is a perspective view showing a state in which a conventional vehicle separator is installed on a road.
FIG. 10 is an explanatory diagram showing a light beam projecting / receiving state by an optical scanning sensor and a regressive reflecting plate constituting a conventional vehicle separator.
11A and 11B show an LED used in a conventional light projecting device. FIG. 11A is a plan view and FIG. 11B is a cross-sectional view.
FIG. 12 is an explanatory diagram showing a relationship of light beams emitted from a conventional light projecting device.
FIG. 13 is a diagram showing a light intensity distribution of a light beam emitted from a conventional light projecting device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical scanning sensor, 2 ... Regression reflecting plate, 3 ... Road, 4 ... Light projection means (light projection apparatus), 6 ... Light scanning means, 8 ... Light reception means, 10 < ₁ > -10 < ₆ > ... Light emitting element (LED) DESCRIPTION OF SYMBOLS 12 ... Projection lens, 14 ... Galvano mirror, 16 ... Drive mechanism, 30 ... Semiconductor chip, 32 ... Lead frame, 33 ... Inclined surface, 34 ... Mold resin, 36 ... Slit, 37 ... Slit hole, 42 ... Rotation board 43 ... Inclined surface, z ... Towing vehicle.

Claims (1)

A light projecting means for emitting light;
Optical scanning means for scanning the light beam emitted from the light projecting means in a direction crossing the road;
A retroreflector disposed oppositely across the optical scanning means;
A light receiving means for receiving reflected light from the regressive reflection plate of a light beam scanned by the light scanning means;
In a vehicle separator that detects a vehicle by a change in the amount of reflected light received by the light receiving means,
The shape of the light beam emitted from the light projecting means is longer in the direction along the vehicle traveling direction of the road than in the direction perpendicular to the road surface of the road. Separator.

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