JPH0651054A - Reflection measuring device for car - Google Patents

Abstract

PURPOSE:To widen the measurable range in distance measuring which is made by using a small-sized body of sensor. CONSTITUTION:A hologram lens 10 is encapsulated in a front glass 21, and a hologram pattern is formed in which only the reflected laser beams from outside of the car onto the surface of the lens are converged on a specified position inside of the car cabin. A driver circuit 3, calculator circuit 6, and laser diode 2 are arranged inside of the body 1 of a sensor. The pulse laser is reflected by an object to be measured, and reflected laser beam is put incident to the hologram lens 10 and converged on a photo-receiving element 5, and the time of photo-reception is sensed. Tone distance is determined from the time difference between light emission and reception. Therein the lens 10 can be structured with a large area because the lens 10 and sensor body 1 are formed discretely, and the quantity of photo-condensation is enlarged. Thus the sensor body 1 can be made in small size, and the measurable range be widened. The hologram lens 10 does not present any obstacle in the view field because it is transparent for visible rays and has no light condensing effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
By irradiating the measured object with a laser and measuring the reflected light, the distance to the vehicle behind, or the distance to an obstacle existing around the vehicle, or the physical quantity such as the speed of the surrounding vehicle. , Relates to a vehicle reflection measuring device adapted to measure.

[0002]

2. Description of the Related Art Conventionally, there has been known an apparatus for measuring a distance to a vehicle ahead by a laser radar while the vehicle is traveling. In this device, a laser irradiation system, an optical lens, and a light receiving system are integrated in a sensor unit. Then, the device irradiates the measured object with a laser, collects the reflected light from the measured object using an optical lens, detects the reflected laser, and detects the relationship between the irradiation laser and the reflected laser. A device for measuring a distance to an object to be measured.

[0003]

In this type of device, in order to secure a certain sensitivity, it is necessary to increase the light receiving area A in proportion to the fourth power of the measurement distance L. That is, in order to widen the dynamic range, it is necessary to increase the diameter of the optical lens. However, since the optical lens is integrally incorporated in the sensor unit, there is a problem that the geometrical size of the sensor unit becomes large when trying to widen the dynamic range.

The present invention has been made to solve the above problems, and an object thereof is to lengthen the measurable distance to an object to be measured and to downsize the sensor unit.

[0005]

SUMMARY OF THE INVENTION According to the present invention, the distance from the object to be measured, the speed of the object to be measured, etc. are measured by irradiating the object to be measured with a laser having a wavelength of invisible light and detecting the reflected light. In the vehicle reflection measurement device mounted on the vehicle to detect,
A hologram lens that is disposed in a light transmitting body that transmits visible light and laser such as a vehicle window glass, a head lamp cover, and a tail lamp cover, and that is transparent to visible light and that collects only reflected light of the laser. A sensor main body that is separate from the hologram lens and that is disposed at a position apart from the hologram lens; and a laser irradiation unit that is disposed in the sensor main body and irradiates the measured object with the laser through a light transmitting body. , A laser light receiving means disposed in the sensor body for receiving the irradiation light of the laser reflected from the object to be measured through the light transmitting body, a laser output by the laser irradiation means, and a reflected light received by the laser light receiving means. To an object to be measured, a calculation means for calculating a physical quantity such as a speed of the object to be measured.

[0006]

The laser is output from the laser irradiation means, passes through the light transmitting body, and is irradiated to the object to be measured. A part of the reflected light from the object to be measured is incident on the hologram lens arranged in the light transmitting body. The hologram lens has a function of selectively condensing only the wavelength of the laser, and the condensed reflected light is incident on the laser light receiving means.
Then, the computing unit computes a physical quantity such as the distance to the object to be measured, the speed of the object to be measured, and the like from the laser output from the laser irradiation unit and the reflected light received by the laser light receiving unit.

As described above, since the hologram lens is separated from the sensor body and is disposed in the light transmitting body such as a window glass of a vehicle, a head lamp cover, a tail lamp cover and the like which transmits visible light and laser, The area of the hologram lens can be made extremely large by making the sensor body small. As a result, since the converging rate of the reflected laser can be increased, it is possible to increase the distance to the object to be measured while the sensor body is small. Further, since the hologram lens is transparent to visible light and does not have a light condensing function, even if the hologram lens is arranged on the window glass, it does not obstruct the view.

[0008]

EXAMPLES The present invention will be described below based on specific examples. FIG. 1 is a diagram showing the configuration of a vehicle reflection measuring apparatus according to this embodiment. The hologram lens 10 is provided in the front windshield glass 21 of the vehicle body 20.
Is enclosed. Front windshield glass 2
1 is formed of two laminated glasses 21a and 21b. A concave portion 22 is formed on the inner surface of one glass 21b, and the hologram lens 10 is inserted into the concave portion 22. And these two laminated glass 21
The hologram lens 10 is enclosed in the front windshield glass 21 by bonding the inner surfaces of a and 21b. The hologram lens 21 is a flat plate made of dichromated gelatin (BCG) that is transparent to visible light, and only the infrared reflection laser that is incident on the surface of the hologram lens 21 from the outside of the vehicle parallel to the horizontal plane is inside the vehicle. A hologram pattern for condensing light at a predetermined position is formed.

On the other hand, on the fixed arm 24 of the inner mirror 23 in the vehicle compartment, the sensor body 1 is fixedly installed at the back of the inner mirror 23. A printed circuit board 7 for arranging each circuit is disposed inside the sensor body 1, and a drive circuit 3 and an arithmetic circuit 6 are disposed on the printed circuit board 7. A laser diode 2 that is driven by the circuit 3 and oscillates an infrared laser is disposed on the drive circuit 3. In addition, the front frame 1a of the sensor body 1 has a collimator lens 4 in front of the laser diode 2.
Is fixed. Further, a light receiving element 5 is fixedly provided on the front frame 1a of the sensor body 1 so as to face the hologram lens 10 at a constant interval. The light receiving element 5
Are connected to the arithmetic circuit 6. Printed circuit board 7
Has a large number of wires 8 for feeding and extracting detection signals
The wire 8 is guided through the inside of the fixed arm 24 to the body 20 and is connected to an on-vehicle battery (not shown) and an on-vehicle control device (not shown).

The arithmetic circuit 6 gives a timing for outputting a laser pulse to the drive circuit 3, inputs a signal output from the light receiving element 5, obtains the light receiving timing of the reflected laser of the pulse, and determines the output timing and the light receiving timing. This is a circuit that calculates the distance to the object to be measured from the time difference and outputs the calculation result to the in-vehicle control device.

In the above structure, the light transmitting body is the front windshield glass 21, the laser irradiating means is composed of the drive circuit 3, the laser diode 2 and the collimator lens 4, and the laser receiving means is composed of the light receiving element 5. The arithmetic means is composed of the arithmetic circuit 6.

Next, the operation of this apparatus will be described. The drive circuit 3 applies a pulse voltage to the laser diode 2 in synchronization with the output timing signal output from the arithmetic circuit 6. As a result, the laser diode 2 outputs a pulsed infrared laser. This laser is collimated by the collimator lens 4, becomes a parallel light beam, enters a vehicle traveling in front of the vehicle in which the present apparatus is mounted, and is reflected by the vehicle. A part of the reflected laser is made incident on the front windshield glass 21 of the own vehicle, and
And passes through the hologram lens 10 encapsulated in. Then, the reflected laser is focused on the light receiving element 5 by the hologram lens 10. Photoelectric conversion is performed by the light receiving element 5, and a pulse signal is output to the arithmetic circuit 6. Arithmetic circuit 6
Calculates the time difference between the output timing of the pulse laser and the light reception timing of the reflection laser, and calculates the distance to the object to be measured from this time difference. The calculation result is transmitted to the vehicle-mounted control device via the wire 8. In this way, the distance between the own vehicle and the vehicle traveling ahead can be measured.

In the above embodiment, since the hologram lens 10 having a large area is provided on the front windshield glass 21, it is possible to increase the distance between the hologram lens 10 and the light receiving element 5. Therefore, the luminous flux of the reflected laser can be increased in accordance with the area of the hologram lens 10 and the area of the light receiving element 5 can be reduced, so that the size of the sensor body 1 can be reduced. Also, the hologram lens 10 can be made to have a wavelength-selective property so as to have a condensing function only for the wavelength of the infrared laser and not to collect a visible light. Therefore, even if the hologram lens 10 is provided on the front windshield glass 21, it is transparent to visible light and does not hinder the visibility.

Although the hologram lens 10 is enclosed in the front windshield glass 21, it may be attached to the surface of the front windshield glass 21. Further, the hologram lens 10 may be formed of photopolymer or silver salt.

Next, another embodiment will be described. Figure 2
In, the hologram lens 10 is enclosed in a transparent headlight cover 30 made of resin. And
The sensor body 1 is placed in the inner chamber 32 of the headlight 31. The configurations and operations of the hologram lens 10 and the sensor body 1 are the same as those in the above embodiment.

As described above, even if the hologram lens 10 is enclosed in the headlight cover 30, the hologram lens 10 is transparent to visible light and does not condense light, so that it is emitted from the headlamp 33. It does not hinder the light.

Also in this embodiment, the hologram lens 10 may be attached to the surface of the headlight cover 30. Further, in the above-mentioned embodiment, the case of distance measurement is described, but it can be applied to velocity measurement of an object to be measured. Further, the present invention can be applied to the measurement of distances and speeds not only for the front but also for rear vehicles, side vehicles, vehicles traveling in an orthogonal direction, and the like.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a vehicle reflection measuring apparatus according to a specific embodiment of the present invention.

FIG. 2 is a configuration diagram showing a vehicle reflection measuring device according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Sensor main body 2 ... Laser diode (laser irradiation means) 3 ... Driving circuit (laser irradiation means) 4 ... Collimator lens (laser irradiation means) 5 ... Light receiving element (light receiving means) 6 ... Arithmetic circuit (arithmetic means) 10 ... Hologram Lens 21 ... Front windshield glass (light transmitting body) 30 ... Headlight cover (light transmitting body)

Claims (1)

[Claims] 1. A vehicle mounted on a vehicle for detecting a reflected light by irradiating a measured object with a laser having a wavelength of invisible light and detecting a distance to the measured object, a speed of the measured object, and the like. In a reflection measuring device for use in vehicles, it is arranged in a light transmitting body that transmits visible light such as a window glass of a vehicle, a head lamp cover, a tail lamp cover, etc. and the laser, and is transparent to visible light, and the reflection of the laser A hologram lens that collects only light, a sensor body that is a separate body from the hologram lens and that is disposed at a position away from the hologram lens, and that is disposed on the sensor body and that passes through the light transmitting body. Laser irradiation means for irradiating the object to be measured with the laser, and irradiation light of the laser reflected from the object to be measured, which is disposed in the sensor body and passes through the light transmitting body. A physical quantity such as a distance to the object to be measured, a speed of the object to be measured, and the like is calculated from the laser light receiving means that emits light, the laser output from the laser irradiation means, and the reflected light received by the laser light receiving means. And a vehicle reflection detection and measurement device having: