JP2002031684A - Reflection measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the shift of the optical axis of an optical system for emitting a light beam in a reflection measuring device for detecting an object existing in an irradiation direction by casting a light beam and receiving the reflection light. SOLUTION: Inside a box constituted of a front case 100 and a rear case 120, a unit body 16 supporting a collimate lens 14 so as to stably maintain the position relation between a laser diode 12 and the collimate lens 14 is directly fixed to an inner case 110 with a tapping screw 114. Therefore even with the occurrence of bending and dimensional variation in a circuit substrate such as a light emission circuit substrate 13 and a power source circuit substrate 90, resulting shift of the optical axis of an optical system consisting of a collimate lens 14 and the like can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection measuring device that irradiates a light beam and receives the reflected light to detect information on an object present in the irradiation direction.

[0002]

2. Description of the Related Art Conventionally, the present invention is applied to a device for detecting an obstacle such as a preceding vehicle and issuing an alarm, and a device for controlling a vehicle speed so as to maintain a predetermined inter-vehicle distance from the preceding vehicle. There is known a reflection measuring device that irradiates a light beam such as a laser beam over a predetermined angle range around a vehicle in order to collect information for recognizing an obstacle, and detects the reflected light.

FIG. 4 is a diagram showing a conventional configuration of this type of reflection measuring device. FIG. 4A is a diagram showing the internal configuration of the reflection measuring device 502 from above, and FIG.
FIG. 5 is a diagram showing the internal configuration of the reflection measurement device 502 from the left (from the right in FIG. 4A).

[0004] As shown in FIG.
A lens unit 510 that generates laser light, a reflecting mirror 520 that reflects the laser light from the lens unit 510 and guides the laser light in a predetermined direction, and an external device that continuously changes the irradiation direction of the laser light guided by the reflecting mirror 520. Polygon mirror 530 that emits light to
An optical system including a light receiving lens 540 for condensing reflected light of the laser light emitted to the outside via the light receiving lens 30 is provided.
The reflected light condensed by the light receiving lens 540 is converted into an electric signal by the photodiode 550.

As shown in FIG. 4, a lens unit 510 includes a laser diode 512 as a light emitting element,
A collimating lens 514, which is an optical element that converts a laser beam generated by a laser diode 512 into a substantially parallel light beam.
And the collimating lens 51 from the laser diode 512.
A lens barrel 516 for guiding the laser beam to the
And a unit support portion 518 which is a support member for maintaining a positional relationship between the lens 12 and the collimating lens 514.

[0006] As shown in FIG.
Is connected to the power supply circuit board 590 through the connection terminal 512a.
And emits light when supplied with power from the power supply circuit board 590. The reflection measuring device 502 includes, in addition to the power supply circuit board 590, a motor drive circuit board 560 for driving the polygon scanner motor 532 to rotate the polygon mirror 530, and an electric signal generated by the photodiode 550 for amplification and amplification. The light receiving circuit board 570 for shaping the waveform and outputting it as a light receiving signal, the power supply from the power supply circuit board 590 to the laser diode 512, and the power supply from the motor drive circuit board 560 to the polygon scanner motor 532 are controlled to control the optical power. While the system scans the laser beam, various calculation processes such as obtaining the position and relative speed of an object present in the scanning area (that is, the scanning area of the laser beam) based on the light receiving signal from the light receiving circuit board 570. And a control circuit board 580 for performing the above. Then, from the power supply circuit board 590, the motor drive circuit board 5
60, power is also supplied to each electronic circuit configured on the control circuit board 580.

The reflection measuring device 502 has a front case 600 for accommodating each of the above-mentioned components, and is formed so as to be insertable into the inside of the front case 600, and holds (supports) predetermined components inside the front case 600.
Inner case 610, which is a structure to perform, and a rear case 620 for closing an opening at the rear of the front case 600.
And Each of the above-mentioned boards, that is, the motor drive circuit board 560, the light receiving circuit board 570, the control circuit board 580, and the power supply circuit board 590 are fixed to the inner case 610 with screws or the like.

[0008]

The unit supporting portion 518 is fixed to the power supply circuit board 590, and supports the collimating lens 514 and the like in this state. That is,
The lens unit 510 is supported by the power supply circuit board 590 inside the reflection measuring device 502.

However, the power supply circuit board 590 itself may warp or change in size over time, or may warp or change in size due to a change in temperature. in this case,
The direction of the optical axis of the optical system for irradiating the laser light (that is, the optical system including the lens unit 510, the reflection mirror 520, and the like) is shifted, and as a result, the scanning range of the laser light is shifted. FIG. 5 schematically shows such a situation, in which the scanning range of the laser beam originally was the range A, but shifted to the range B, for example.

The range in which an object can be recognized (hereinafter, referred to as a "measurement area") is a range in which a scanning range of laser light and a range in which reflected light can be received (hereinafter, referred to as a "receivable range") overlap. Therefore, in order to prevent the size of the measurement area from changing even when the scanning range of the laser beam is shifted as described above, the receivable range covers the entire scanning range of the laser beam. Need
For that purpose, the light receiving range must be sufficiently large.

However, since there is a limit in enlarging the receivable range, even if the scanning range is deviated, the size of the scanning range is determined in advance in consideration of the expected deviation so as to be included in the receivable range. Need to be set small. Then, as a result, the measurement area becomes narrow.

The present invention has been made in view of such a problem, and an object of the present invention is to suppress displacement of an optical axis of an optical system for emitting a light beam in a reflection measuring device.

[0013]

Means for Solving the Problems and Effects of the Invention In a reflection measuring apparatus according to the present invention (described in claim 1) made to solve the above-mentioned problems, a light emitting element and light generated by the light emitting element are obtained. An optical system for emitting a light beam to the outside of the reflection measuring device and receiving the reflected light, and a structure for holding components of the optical system in a predetermined positional relationship are provided. ing. An optical element which is one of the components of the optical system is also provided. The optical element is supported by a support member, whereby the positional relationship between the optical element and the light emitting element is kept constant, but the support member is directly fixed to the structure.

That is, in the conventional reflection measuring device, the supporting member is a circuit board (for example, the above-described power supply circuit board 590).
The optical element as a component of the optical system and the other components may have been affected by the circuit board. Instead of fixing it to the circuit board,
Since the support member is directly fixed to the structure, the positional relationship is not affected by the circuit board.

Therefore, in the reflection measuring device of the present invention (claim 1), it is possible to prevent the optical axis of the optical system for irradiating the light beam from being shifted due to the warpage or dimensional change of the circuit board. Can be. Therefore, the deviation of the optical axis is suppressed. For example, when the reflection measuring device is configured to scan the light beam and detect an object in the scanning range, the scanning range should be set wider. And the object can be detected over a wider range.

In the case where the support member is directly fixed to the structure as described above, it is possible to prevent the optical axis of the optical system for emitting the light beam from being shifted with the passage of time. It is preferable to suppress variations in the optical axis of each reflection measuring device. That is, if the variation in the position of the support member on the structure is large when comparing individual products,
The optical axis of the optical system that emits the light beam also has large variations among products. Therefore, the scanning range set in consideration of the magnitude of the expected shift becomes small,
As a result, the measurement area also becomes narrow.

Therefore, as described in claim 2, a fitting portion that can be fitted to each other is formed on the support member and the structure, and the fitting portion on the support member side and the fitting portion on the structure side are fitted. Thus, the position of the support member in the structure may be determined. Then, it is possible to easily reduce a positional error when attaching the support member to the structure. That is, variations in the optical axis of the optical system that emits the light beam from product to product can be suppressed, and the measurement area can be widened.

The circuit board (light emitting circuit board) for emitting light from the light emitting element may be fixed by being supported by a support member. That is, the light emitting circuit board may be supported by the structure, but in this case, the position of the light emitting circuit board is easily restricted by the specific structure of the structure, and as a result, the support member or the optical element The position is also subject to the restrictions. On the other hand, if the light-emitting circuit board is supported by the support member as described in claim 3, it is not necessary to support the light-emitting circuit board by the structure, so that the inside of the reflection measuring device including the support member and the optical element is included. This has the effect of increasing the degree of freedom in the layout of the components in.

It is more preferable that the light emitting circuit board is formed separately from the power supply circuit board which manages the power required in the reflection measuring device. That is,
Conventionally, an electric circuit for causing a light emitting element to emit light has been formed on a power supply circuit board. However, in this case, the board becomes large, and the degree of freedom in layout is reduced. On the other hand, if the power supply circuit board and the light emitting circuit board are configured separately as described in claim 4, the light emitting circuit board can be made relatively small,
There is an effect that the possibility of being restricted by the layout can be reduced.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. The reflection measurement device described below as one embodiment is disposed at the front of the vehicle so that the laser light can be emitted in the traveling direction of the vehicle and the reflected light can be received. .

FIG. 1 is a perspective view showing the entire configuration of the reflection measuring device 2, and shows a state in which the reflection measuring device 2 is disassembled into its components from an obliquely upper left front. FIG. 2 is a diagram showing the arrangement of the components inside the reflection measurement device 2 from above, and FIG. 3 is a diagram showing a lens unit 10, a reflection mirror 20, and the like described later inside the reflection measurement device 2.
FIG. 3 is a diagram illustrating an arrangement of a polygon mirror 30 and the like from the right side.

As shown in FIG. 1 and the like, the reflection measuring device 2 of the present embodiment has the following optical system. That is, the optical system of the reflection measuring device 2 includes a lens unit 10 that generates substantially parallel laser light, a reflection mirror 20 that reflects the laser light emitted from the lens unit 10 and guides the laser light in a predetermined direction, and a reflection mirror 20. A polygon mirror 30 that reflects the laser light guided by the mirror and continuously changes the irradiation direction thereof, and a light receiving lens 40 that condenses the reflected light of the laser light irradiated through the polygon mirror 30. .
The reflected light collected by the light receiving lens 40 is received by the photodiode 50 and is converted into an electric signal.

As shown in FIGS. 2 and 3, the lens unit 10 includes a laser diode 12 for generating a pulsed laser beam in the infrared region, and a laser beam supplied from the laser diode 12 by supplying power thereto. A light emitting circuit board 13 for generating laser light, a collimating lens 14 for causing the laser light generated by the laser diode 12 to be substantially parallel and emitting the light from the lens unit 10, and these constituent parts 12 and 1.
Unit housing 16 for holding laser beams 3 and 14 and guiding laser light from laser diode 12 to collimating lens 14
And

As shown in FIG. 1, the reflection measuring device 2 comprises:
In addition to the light emitting circuit board 13, a plurality of electronic circuit boards are provided as follows. That is, the reflection measuring device 2 includes a motor driving circuit board 60 for driving the polygon scanner motor 32 to rotate the polygon mirror 30, and a photodiode 50 mounted thereon and an electric signal generated by the photodiode 50. The optical system scans the optical system by operating the electronic circuits formed on the light-receiving circuit board 70, which amplifies and waveform-shapes and outputs the light-receiving signal, and the light-emitting circuit board 13 and the motor drive circuit board 60, respectively. And a control circuit board 80 that performs various arithmetic processing such as finding the position and relative speed of an object present in the scanning area (ie, within the scanning area of the laser beam) based on the light receiving signal from the light receiving circuit board 70. Power is supplied to the electronic circuits respectively formed on the light emitting circuit board 13, the motor drive circuit board 60, and the control circuit board 80. A power supply circuit board 90 for, and a.

The reflection measuring device 2 has a structure for holding and protecting the above-mentioned components at predetermined positions. That is, the reflection measuring device 2 includes a front case 100 for accommodating each of the above components, and a front case 100 that is formed to be insertable inside the front case 100 and holds the above components inside the front case 100 with high positional accuracy. Inner case 11 cast from aluminum
0 and a rear case 120 for closing an opening at the rear of the front case 100.

At the front of the front case 100, an emission window 102 for emitting the laser light reflected by the polygon mirror 30 to the outside of the front case 100, and an entrance for receiving the reflected light corresponding to the laser light. A window 104 is formed. In order to prevent water droplets and the like from entering the inside of the front case 100 through the exit window 102 and the entrance window 104, a plate-like protection member 130 is provided.
Are arranged inside the front part of the front case 100 so as to cover the exit window 102 and the entrance window 104. Specifically, protection member 130 is arranged between the front of inner case 110 and the front of front case 100 housed inside front case 100. The protection member 13
Numeral 0 is formed of a material capable of transmitting light (for example, transparent glass or resin), and does not prevent light from passing through the exit window 102 and the entrance window 104.

A packing 140 with an O-ring is disposed between the protection member 130 and the front part of the front case 100 to prevent water droplets or the like from entering therethrough. The packing 140 with an O-ring is formed by integrally molding a rubber O-ring 142 having substantially the same shape as the exit window 102 and a rubber O-ring 144 having substantially the same shape as the entrance window 104. Then, the inner case 110 is pressed against the inside of the front part of the front case 100 via the packing 140 with the O-ring and the protection member 130, so that the airtightness of the exit window 102 and the entrance window 104 is ensured.

On the other hand, an O-ring 146 is disposed between the front case 100 and the rear case 120 to prevent water droplets or the like from entering therethrough. A connector 150 is provided on the outer surface of the rear case 120 for inputting / outputting a signal to / from the reflection measuring device 2 and supplying power to the reflection measuring device 2. It is inserted inside the device 2. An O-ring 148 is disposed between the connector 150 and the rear case 120 to prevent water droplets and the like from entering through the through hole 122 of the rear case 120.

The components of the optical system such as the lens unit 10, the reflection mirror 20, the polygon mirror 30, and the light receiving lens 40, and the circuit boards 13, 60, 70, 80, and 90 described above.
Is a reflection measuring device 2 using the inner case 110 as a support.
Of the lens unit 10, the reflection mirror 20, and the polygon mirror 30.
Is arranged in the space on the right side inside the reflection measuring device 2 as shown in FIG.

As shown in FIG. 3, a space in which the lens unit 10, the reflection mirror 20, and the polygon mirror 30 are arranged is vertically divided by a partition 112 formed as a part of the inner case 110. This partition 11
The lens unit 10 and the reflection mirror 20 are arranged in a space above the space 2, and the polygon mirror 30 is arranged in a space below the space. In addition, as shown in FIG. 2, an opening 118 is formed in the partition wall 112 to allow a laser beam from the reflection mirror 20 to the polygon mirror 30 to pass therethrough.

The lens unit 10 is fixed to the upper surface of the partition 112 by screwing a tapping screw 114 penetrating the partition 112 from below into the unit housing 16. On the upper surface of the partition 112, a plurality of protrusions 115 for determining the position of the lens unit 10 are formed.
Correspondingly, a plurality of fitting holes 18 capable of fitting with the protrusions 115 are formed in the unit housing 16. The protrusion 115 is fitted into the fitting hole 18 of the unit housing 16.
The lens unit 10 is fixed on the inner case 110 so as to be able to emit laser light in a certain direction.

The reflection mirror 20 is fixed to the inner case 110 by a reflection mirror support member 22 in front of the lens unit 10 (ie, in the direction in which the laser light is emitted when viewed from the lens unit 10). On the other hand, the polygon mirror 30 is attached to a rotating shaft of a polygon scanner motor 32 fixed to a motor drive circuit board 60 formed using a metal plate as a base substrate. By attaching the motor drive circuit board 60 to the inner case 110 with the screws 62, the polygon mirror 30 is held by the inner case 110 so as to be able to rotate around a certain axis.

The reflection measuring device 2 of the present embodiment configured as described above operates as follows. First, when the laser light emitted from the laser diode 12 is emitted from the collimating lens 14 as substantially parallel light, the laser light enters the reflection mirror 20. The laser light reflected by the reflection mirror 20 passes through the partition opening 118 and then enters the polygon mirror 30. Then, the laser light reflected by the polygon mirror 30 passes through the protection member 130 and is emitted from the emission window 10.
2 is emitted to the outside of the reflection measuring device 2. The emitted laser light irradiates vehicles and objects on the road,
The reflected light passes through the entrance window 104 and the protection member 130, is further condensed by the light receiving lens 40, and reaches the photodiode 50, where it is converted into an electric signal. The laser light emitted from the lens unit 10 is pulsed light, and based on the light emission timing, the time difference from light emission to light reception, and the like, the position information (distance, direction) of the object with respect to the reflection measurement device 2, and the like. Get information.

The reflection measuring device 2 of the present embodiment described above
According to the above, the following effects are obtained. That is, in the reflection measuring device 2, the collimating lens 14 is supported inside the housing composed of the front case 100 and the rear case 120 so that the positional relationship between the laser diode 12 and the collimating lens 14 is kept constant. The unit housing 16 to be mounted is
Directly fixed by. Therefore, the light emitting circuit board 1
Even if warpage or dimensional change occurs in a circuit board such as the power supply circuit board 3 or the power supply circuit board 90, it is possible to prevent the optical axis of the optical system including the collimator lens 14 and the like from being displaced by the warp and the dimensional change. The scanning range of the light beam can be set wide, and the object can be detected over a wider range.

The partition wall 112 forming a part of the inner case 110 is provided with a projection 115 and the unit housing 16 is provided with a fitting hole 18.
When the fitting hole 18 is fitted to the outside of the lens unit 15 (that is, the projection 115 is fitted to the fitting hole 18),
Is fixed on the inner case 110 so that laser light can be emitted in a certain direction. That is, it is possible to reduce the displacement when attaching the unit housing 16 to the inner case 110, and as a result, it is possible to widen the measurement area.

The light emitting circuit board 13 is connected to the power supply circuit board 9
Since the light-emitting circuit board 13 is formed separately from the light-emitting circuit board 0 and is fixed by supporting the light-emitting circuit board 13 with the unit housing 16, the degree of freedom in the layout of the components in the reflection measurement device 2 can be improved. it can.

As described above, one embodiment of the present invention has been described. However, the present invention is not limited to the above embodiment, and can take various forms. For example, in the above embodiment, the inner case 110 corresponding to the “structure” in the claims has been described as being cast from aluminum, but is not limited thereto. What is necessary is just to be able to hold the component parts in the housing with high positional accuracy, and it is sufficient to use a material with little change (temperature change, aging change, etc.).

In the above embodiment, the unit housing 16 is fixed to the inner case 110 with the tapping screw 114.
However, the present invention is not limited to this, and various means can be adopted. In the above embodiment, the reflection measurement device that scans the light beam has been described as an example. However, the present invention is not limited to this.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of a reflection measurement device according to an embodiment.

FIG. 2 is a diagram showing a configuration of a reflection measuring device from above.

FIG. 3 is a diagram showing the configuration of the reflection measuring device from the right.

FIG. 4 is a diagram showing an example of a conventional reflection measuring device.

FIG. 5 is a diagram showing a state where a scanning range is shifted.

[Explanation of symbols]

 2 Reflection measuring device 10 Lens unit 12 Laser diode 13 Light emitting circuit board 14 Collimating lens 16 Unit housing 18 Fitting hole 90 Power supply circuit board 100 Front case 110 Inner case 112 Partition wall 115 Projection 120 ... Rear case

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Claims (4)

[Claims] A light emitting element for generating a light beam, an optical system for emitting a light beam generated by the light emitting element to the outside, and receiving a reflected light of the emitted light beam; and the optical system. And a structure for holding a plurality of constituent components constituting a predetermined predetermined positional relationship, and for maintaining a constant positional relationship between the light emitting element and an optical element forming one of the constituent components. And a support member for supporting the light emitting element. The optical system irradiates a light beam to the outside and receives reflected light of the illuminated light beam, thereby obtaining information on an object existing in the irradiation direction. A reflection measurement device, wherein the support member is directly fixed to the structure. 2. The reflection measuring device according to claim 1, wherein a fitting portion that can be fitted to each other is formed in the support member and the structure, and the fitting portion on the support member side and the fitting portion on the structure side. Wherein the position of the support member in the structure is determined by fitting the two. 3. The reflection measuring device according to claim 1, further comprising a light emitting circuit board for causing the light emitting element to emit light, wherein the light emitting circuit board is fixed by being supported by the support member. Characteristic reflection measurement device. 4. The reflection measurement device according to claim 3, wherein the light emitting circuit board is formed separately from a power supply circuit board that manages power required in the reflection measurement device. Reflection measuring device.