JPS6049277A - Car laser radar equipment - Google Patents

Abstract

PURPOSE:To detect securely the distance between cars and their relative speed by arranging a laser light emission part within the focal length of a lens and expanding the beam diameter of a laser beam. CONSTITUTION:The laser light emission part 22 is arranged closer to the lens 21 than its focal length. The laser light from the light emission part 22 is increased in beam diameter toward a car 1 running ahead to obtain a laser beam 3, which is about as wide as one lane of a road at the maximum necessary detection distance of the laser radar device 2. Therefore, the beam 3 illuminates the whole of the car running ahead and its reflected light reaches the photodetecting element of the device 2 to detect securely the distance to the car and relative speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is designed to detect the distance or relative speed to a preceding vehicle by turning to the preceding vehicle and emitting a sea light! ! 4! The present invention relates to an on-vehicle rail system that emits light and receives reflected light.

Detect the distance 1 or relative speed to the preceding vehicle and determine whether it is appropriate. Some vehicles are equipped with devices that control vehicle speed to maintain a safe intermediate distance, or issue a warning when vehicles are approaching each other.

In this case, a laser radar device is used as a means for detecting the inter-vehicle distance or the phase χ1 speed. This laser radar device emits pulsed laser light 4J toward the preceding vehicle, receives the laser light reflected by the preceding 11 vehicles with a light receiving element, and detects the inter-vehicle distance based on the time from illumination Ul to light reception. Furthermore, the relative speed is detected from the change in inter-vehicle distance over a certain period of time.

A conceptual diagram of the second laser radar device is shown in FIG.

The laser light emitted by the laser emitting unit [RO] in the laser radar device R is converted into parallel light [3] by the lens I, and is irradiated onto the preceding vehicle (3). Since the 1 to 100 rays'IJ' light is considered to be a parallel beam with a relatively small diameter, the irradiated light may cause damage to the 1st rank of the preceding vehicle V. If the reflected light does not reach the light receiving element in the laser radar device, it may become impossible to detect the vehicle distance +jljMll or the relative speed.

In view of these conventional problems, it is an object of the present invention to widen the beam diameter of the laser beam so that the laser beam irradiates a relatively wide area on the vehicle body of the preceding vehicle. The objective is to ensure that the laser beam is irradiated onto the portion of the light receiving element that reflects light due to its bend.

In order to achieve this object, the present invention focuses the laser emitting part on the lens so that the spread width of the laser beam irradiated to the preceding vehicle is about the width of one lane of the 3rL road at the maximum required detection distance. It is characterized by being placed close to each other.

According to the present invention, as a result of the laser emitting section being arranged closer to the lens than the focal length of the lens, the beam diameter of the laser beam is widened, and furthermore, this broadening width is larger than that of the road at the maximum required detection distance. It is said to be about the width of a lane, so the laser beam will illuminate the entire or almost the entire vehicle in front).
The laser beam can be reliably irradiated onto the portion where the light is reflected toward the light-receiving element. For example, ilj: A reflector is always attached to the rear of both cars, and by irradiating this reflector with laser light, the reflected light can be reliably received by the light receiving element, and the 11 vehicles ahead can be reliably captured. I can do it.

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

FIG. 2 is a conceptual diagram of one embodiment. In the laser radar device 2, the laser emitting section 22 is arranged iJ closer to the lens example than the focal length of the lens 21. FIG. Therefore, the laser light emitted by the laser emitting unit 22 becomes a beam 3 whose beam diameter is gradually expanded toward the preceding vehicle l, and at the maximum required detection distance of the laser radar device 2, only one lane of the road It is said to be approximately 3.7 meters wide.

Therefore, the laser beam 3 emitted from the laser radar device 2 will irradiate almost the entirety of the preceding vehicle, and the irradiated light will be transmitted to the light receiving element of the laser radar device 2 (not shown). The laser beam 3 can be irradiated to a range including the portion reflected by the laser beam 40.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a conventional laser radar device, and FIG. 2 is a conceptual diagram of an embodiment of the present invention. 1---1 Leading vehicle 2--1-Laser radar device 21--Lens 22--Laser emitting section 3--Laser beam Applicant Toyota Motor Corporation

Claims (1)

[Scope of Claims] (1) A laser radar device for a middle crosspiece that irradiates a preceding vehicle with a laser beam at a distance of lii and receives reflected light in order to detect the distance or relative speed to the preceding vehicle, The laser emitting part is arranged close to the focal length of the lens so that the spread width of the laser beam irradiated to the preceding vehicle is about the width of one lane of the road at the maximum required detection distance. Car 1. Is radar + J router device.