JPS5987384A - Detector of vehicle to be measured - Google Patents

Abstract

PURPOSE:To detect a specified vehicle even if another vehicle travels by providing an optical rotating member making coincide the axis of polarization of the light transmitted through the first polarizing member with the axis of polarization of the second polarizing member, in the vehicle to be measured. CONSTITUTION:If the optical rotating member 15 of a vehicle 12 to be measured comes to an optical device 9 when the vehicle 12 passes laser projecting and receiving devices 4 and 8, the laser beam having a vertical polarized axis transmitted through the first polarizing member 10 is rotated for the polarization axis by 90 deg. by the optical rotating member 15 to be made horizontal, and the laser beam reaching the second polarizing member 11 in this state is transmitted through the second polarizing member 11 and is made incident to the laser light receiver 8 to turn on the light receiver 8 to output a detection signal to a measuring circuit. If another vehicle 20 having no optical rotating member 15 passes between the laser projecting and receiving devices 4 and 8, the laser beam transmitted through the first polarizing member 10 is intercepted by the vehicle 20 and is not made incident to the light receiver 8 to turn off the light receiver 8 as it is.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a detection device for a vehicle to be measured that is capable of detecting a vehicle to be measured from among a plurality of vehicles.

Generally, the detection device for the vehicle to be measured is installed on both sides of the test course and used to measure the vehicle's passing time, passing speed, etc. Conventionally, this type of device was
A light-shielding type equipped with a phototube was used, and this was designed to detect the vehicle to be measured when a traveling vehicle blocked the optical path between the emitter and the receiver.

By the way, test courses are generally designed so that multiple vehicles can run at the same time, and when multiple vehicles run at the same time, the conventional light-blocking type detection device described above cannot distinguish between the vehicle to be measured and other vehicles. During measurements, it was necessary to prohibit other vehicles from driving, which resulted in problems with the efficiency of using the test course.

The present invention has been made in view of such conventional problems, and includes a first polarizing member on the projector side and a second polarizing member that does not transmit the light transmitted through the first polarizing member on the receiver side. established,
The original polarization axis transmitted through the first polarization member to the vehicle to be measured is
It is an object of the present invention to provide a detection device for a vehicle to be measured that can detect a specific vehicle even when other vehicles are traveling by providing an optical rotation member that matches the polarization axis of the polarization member.

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show an embodiment of the present invention. In the figures, 1 is a vehicle running path that is long in the front-back direction (perpendicular to the paper surface of the 1st drawing), and on the left side of the vehicle running path 1 is a projector mounting frame. 2 is fixed by an anchor bolt 2a1, and a laser projector 4 is accommodated and held in a projector case 3 attached to the upper end of the mounting frame 2. A power unit 5 is connected to the laser projector 4, and a power unit 5 is connected to the power unit 5. is connected to a power source by a lead wire 5a.

Further, a light receiver mounting frame 6 is fixed to the right side of the vehicle running path 1, and a laser light receiver 8 is accommodated and held in a light receiver case 7 attached to the upper end of the frame 6.
is connected to a measurement circuit (not shown) by a lead wire 8a, the laser receiver 8 faces the laser projector 4, and the optical path 9 between the laser projector and the receivers 4 and 8 is horizontal and It is perpendicular to the traveling direction of the vehicle traveling path 1.

A first mounting bracket 10a is attached to the vehicle travel path 1 side of the projector case 3, and the bracket 10a
A first polarizing member 10 is accommodated and held within the optical path 9 at right angles to the optical path 9, and the polarizing axis of the first polarizing member 10 is in the vertical direction. In addition, the vehicle traveling path 1 of the receiver case 7
A second mounting bracket 1a is attached to this bracket 10a, and a second polarizing member 11 is accommodated and held at right angles to the optical path 9 within the bracket 10a.
The polarization axis of the light beam 1 is parallel to the horizontal direction f, so that the light transmitted through the first polarizing member 10 is not transmitted.

Further, in the center of the front bumper 12a of the vehicle 12 to be measured, a T-shaped mounting bracket 130 base 13λ is fixed with bolts using the license plate mounting hole, and the holding portion 13b of the bracket 13 protrudes forward. There is. Two transparent acrylic plates 14 are bolted and fixed to the holding part 13b, and both acrylic plates 1
An optical rotation member 15 consisting of a 1/2 wavelength plate is held between the 4 and 4 at the same height as the optical path 9, and the optical rotation member 15 sets the polarization axis of the light transmitted through the first polarization member 10 at 90'. It is rotated to be horizontal and aligned with the polarization axis of the second polarization member 11.

Next, the effects will be explained using FIGS. 3(a) to 3(C). Here, Fig. 3(a) shows the case where no vehicle is present between the laser emitter and the receiver 4°8, and Fig. 3(b), (
C) is between the transmitter and the receiver 4.8, and the vehicle to be measured 12.8. Other car 2
FIG. 2 is a schematic configuration diagram for explaining the effect when each 0 passes through.

First, if there is no vehicle between the laser projector and the receivers 4 and 8, only the laser beam projected from the laser projector 4 has a vertical polarization axis! It passes through the sl polarizing member 10. The transmitted laser beam then travels along the optical path 9, and when it reaches the second polarizing member 11f, it is blocked here because the polarization axis of the polarizing member 11 is horizontal, so that the laser beam is directed to the laser receiver 8. No light is incident, and the light receiver 8 remains off.

Next, when the measured vehicle 12 passes between the laser projector and the light receiver 4.8, when the optical rotation member 15 of the measured vehicle 12 comes to the optical path 9, the light beam passes through the first polarizing member 10. A laser beam with a vertical polarization axis is directed to the optical rotation member 15.
The polarization axis is rotated by 90 degrees and becomes horizontal, and when it reaches the second polarizing member 11 in this state, it is transmitted through this and enters the laser receiver 8, which is turned on. A detection signal will be output to the measurement circuit.

Note that the acrylic plates on both sides of the optical rotation member 15 are transparent and do not affect the polarization axis of the laser beam.

Further, when another vehicle 20 that does not have the optical rotation member 15 passes between the laser projector and light receivers 4 and 8.

The laser beam transmitted through the first polarizing member 10 is blocked by the other vehicle 20 and does not enter the laser receiver 8, and the receiver 8 remains turned off.

As described above, in this embodiment device, the optical rotation member 15 is attached to the vehicle to be measured 12 so that the polarization axis of the laser beam transmitted through the first polarization member 0 coincides with the polarization axis of the second polarization member 11. Therefore, a charged vehicle can be detected even when other vehicles are traveling on the vehicle travel path 1.

Therefore, by providing the device of the above embodiment at the measurement start position and measurement end position of the test course, it is possible to measure the vehicle speed, required passing time, etc. of the vehicle to be measured.

As described above, according to the detection device for a vehicle to be measured according to the present invention, a light emitter and a light receiver are provided facing each other on both sides of the vehicle traveling path, and the first polarizing member is placed on the side of the light emitter, and the first polarizing member is placed on the side of the redundant receiver. A second polarizing member that does not transmit light that has passed through the first polarizing member is provided, and a chest member that makes the polarization axis of the first polarizing member coincide with the polarizing axis of the second polarizing member is provided on the vehicle to be measured. Because of this provision, a charged vehicle can be detected even when another vehicle is traveling on the vehicle travel path, and this has the effect of widening (improving) the usage efficiency of the vehicle travel path.

[Brief explanation of drawings]

FIG. 1 is a front view of the projector, light receiver, and polarizing member of a detection device for a vehicle to be measured according to an embodiment of the present invention; FIG. 2 is a side view of the vehicle to be measured; b) is a perspective view of the optical rotation member portion, and FIGS. 3(a) to 3(C) are schematic configuration diagrams for explaining the function. 1... Vehicle running path, 4... Floodlight, 8 ... Light receiver, 1°... First polarizing member, 11... Second polarizing member,
12... Vehicle to be measured, 15... Chest member. Patent applicant: Toyo Kogyo Co., Ltd.

Claims (1)

[Claims] (1) A light projector and a light receiver are provided facing each other on both sides of the vehicle running path, a first polarizing member is provided in front of the light projector near the light projector, and the first polarizing member and the polarizing member are provided in front of the light receiver near the light receiver. A second polarizing member is provided so that the light having different axes and transmitted through the first polarizing member is not transmitted, and optical rotation is made to match the polarization axis of the light transmitted through the first polarizing member with the 44-element axis of the second polarizing member. A detecting device for a vehicle to be measured is characterized in that a member is provided on the vehicle to be measured so as to detect the source via the optical rotation member only when the vehicle to be measured passes by.