JPH0954233A - Optical module and laser radar device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to obtain an optical module which is improved in accuracy and yield without an increase in man-hours and cost and is stable to a wide range of temp. changes by decreasing the variations in positioning of optical elements and optical parts. SOLUTION: Adhesives 5 are interposed as elastic materials between a substrate 2 for holding a semiconductor laser 1 which is the optical element and a substrate 4 holding a lens 3 which is the optical parts. The spacing between both substrates 2 and 4 is set by means of screws 6 which are space setting means in the state that the adhesives 5 are held compressed. The joining strength between both substrates 2 and 4 is increased by such constitution coupled with the adhesives 5 and the screws 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module for projecting light emitted from an optical element through an optical component and a laser radar device using the same.

[0002]

2. Description of the Related Art Conventionally, in this type of optical module, when positioning an optical component such as a lens with respect to an optical element for light emission, it has been attempted to stably assure projection of a thin light beam over a wide temperature range. Fine adjustment accuracy on the order of μm is required. The positioning adjustment method is shown in FIG.
As shown in FIG. 3, there is a method of fixing the substrate 2 holding the optical element 1 and the substrate 4 holding the lens 3 with screws 6 or an adhesive agent. With such a structure, a material having a predetermined linear expansion coefficient is used for both substrates 2 and 4, and thermal expansion and contraction according to high temperature and low temperature are absorbed by each other.
The distance between the optical element 1 and the lens 3 is kept constant, and the temperature stability is improved. However, in order to achieve high positioning accuracy with such a configuration, it is difficult to mass-produce the substrates 2 and 4 because high processing accuracy is required. Therefore,
As shown in FIG. 2, by adjusting the distance between the substrate 2 holding the optical element 1 and the substrate 4 holding the lens 3 with the adhesive layer 5, a machining error is absorbed and high positioning accuracy is realized. There is.

[0003]

However, the conventional structure as described above has the following problems. (1) The adhesive is vulnerable to severe environment, especially high temperature and high humidity, and there is concern about reliability. (2) Positioning by the adhesive is determined by the amount of shrinkage of the adhesive when it is cured. Therefore, if the amount of shrinkage varies, the yield decreases. (3) In order to maintain the reliability of the adhesive force, it is necessary to perform processing such as cleaning the adhesive surface of the substrate with alcohol, which increases the number of steps. (4) In order to increase the adhesive force, the bonding surface of the substrate needs to be processed by sandblasting or the like, which leads to an increase in cost. (5) In order to obtain a sufficient adhesive force in bonding with only an adhesive, it is necessary to increase the adhesive area, and the optical module becomes large.

The present invention has been made to solve the above problems, and an elastic body is interposed between a first member holding an optical element and a second member holding an optical component, And, by using a member for setting the interval between the two members, it is possible to reduce the variation in positioning of the optical element and the optical component and improve the accuracy and yield, without increasing man-hours and cost, An object of the present invention is to provide an optical module which is stable and reliable against a wide range of temperature changes and a laser radar device using the same.

[0005]

To achieve the above object, the present invention provides an optical module for projecting light emitted from an optical element through an optical component such as a lens. Second member and a second holding optical component
Member, an elastic body interposed between both members, and a gap setting means for setting a gap between both members in a state where the elastic body is compressed. With this configuration, due to the synergistic effect of the elastic body and the interval setting means, it is easy to finely adjust the variation in the interval between both members, and the positioning can be performed with high accuracy. Moreover, the yield is increased, and stable characteristics can be obtained over a wide temperature range.

In the above, a screw can be used as the space setting means, and an adhesive can be used as the elastic body. Further, if at least one of the first member and the second member is a light transmissive material and the elastic body is a photocurable resin, they can be cured by light irradiation, and positioning and fixing can be performed. The process is simple. Further, the optical element may be a light emitting semiconductor element and the optical component may be a lens. Further, the elastic body may have a structure that does not contact the screw. Also, the screw may be a light transmissive material.

The present invention also includes the above optical module,
And a signal processing circuit for processing an electric signal output from a light receiving element for detecting light intensity, the optical element of the optical module emits a laser beam, and projects the laser beam onto a target object.
This is a laser radar device in which reflected light from the target object is received by a light receiving element, and the signal processing circuit measures the distance to the target object based on the time delay from light emission to light reception. With this configuration, the optical module can stably emit a thin light beam with high density, so that highly accurate measurement is possible even if the target object is at a long distance. Further, the present invention is a vehicle equipped with the laser radar device described above, and a photoelectric sensor equipped with an optical module.

The present invention further includes the above optical module, an optical scanning device for scanning light, and signal processing means for processing an electric signal output from a light receiving element for detecting light intensity. An optical sensor device that scans the emitted light beam with an optical scanning device to illuminate an object, receives the reflected light from the object with a light receiving element, and detects information such as the presence or absence of the object and the shape with the signal processing means. Is. Furthermore, the present invention includes the above optical module, an optical scanning device that scans light, and a signal processing unit that processes an electric signal output from a light receiving element that detects light intensity, and emits from the optical module. A code information reading device that scans a light beam with an optical scanning device to illuminate an object having code information such as a bar code, receives reflected light from the object with a light receiving element, and reads the code information with a signal processing means. Is.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a schematic sectional view of a light projecting collimator module according to an embodiment of the present invention. The projecting collimator module is a semiconductor laser (optical element).
A light source substrate (first member) 2 made of aluminum containing 1;
A lens substrate (second member) 4 made of a polycarbonate resin including a plano-convex aspherical lens (optical component) 3 made of glass, and an ultraviolet curing adhesive (elasticity) filled in a gap between the light source substrate 2 and the lens substrate 4. It is composed of a body 5 and screws (interval setting means) 6 made of aluminum. The semiconductor laser 1 is fixed to the light source substrate 2, and the plano-convex aspherical lens 3 is fixed to the lens substrate 4.

In this embodiment, in order to maintain high collimating performance over a wide temperature range, the plano-convex aspherical lens 3 is used.
Although the glass material is used for the above, a resin (plastic) material may be used. When a plastic lens is used, the lens and the lens substrate 4 may be integrated as shown in FIG. A tap hole 7 is cut in the light source substrate 2, and the lens substrate 4 is screwed through a layer of an ultraviolet curable adhesive 5 cured by a screw 6 penetrating a screw hole 8.

In this embodiment, the screw 6 and the ultraviolet curable adhesive 5 have a structure in which they do not come into contact with each other, but as shown in FIG. However, in that case, it is necessary to apply a release material to the screw 6 in advance or to use the screw 6 having a small adhesive force with the ultraviolet curable adhesive 5. Further, as shown in FIG. 8, the screw holes 8 may be filled with the ultraviolet curable adhesive 5. In this case, the light source board 2
The adhesive force between the lens substrate 4 and the lens substrate 4 is further increased. An example of the ultraviolet curable adhesive 5 is Loctite (registered trademark) 3211. This adhesive is a resin whose main component is urethane acrylate having thixotropic (property to liquefy or solidify by ultrasonic waves)
Cured by UV irradiation.

Next, the lens positioning procedure of the light projecting collimator module in this embodiment will be described. 4 and 5 are a cross-sectional view and a perspective view thereof, respectively, after the ultraviolet curable adhesive 5 is applied to the adhesive surface on the light source substrate 2 side. The positioning procedure is as follows. (First step) The semiconductor laser light source 1 is fixed to the light source substrate 2. Two or more semiconductor laser light sources 1 may be used.

(Second step) The plano-convex aspherical lens 3 is fixed to the lens substrate 4. Light source substrate 2 is aluminum, lens substrate 4
By using a material such as a resin such as polycarbonate having different linear expansion coefficients, excellent collimating performance can be obtained over a wide temperature range. If the plano-convex aspherical lens 3 is a plastic lens, the weight can be reduced, and further, by using a Fresnel lens as shown in FIG. 9, the weight can be further reduced.

(Third step) An ultraviolet curable adhesive 5 is applied to the adhesive surface on the light source substrate 2 side. (Fourth step) After passing the screw 6 through the screw hole 8, tap the hole 7
Screwed in. At this time, as shown in FIG. 10, the bearing surface of the screw 6 is sufficiently floated with respect to the lens substrate 4. In this embodiment, the screws 6 are preliminarily set before the ultraviolet curable adhesive 5 is cured.
However, it is not necessary to previously insert the screw 6 before curing. However, when the screw 6 is not inserted before curing, it is necessary to make the structure in which the positions of the screw holes 8 and the tap holes 7 are aligned. Further, although the screw 6 made of aluminum is used in the present embodiment, a screw made of resin such as polycarbonate may be used. In this case, the bonding strength is weakened, but there is an advantage that the ultraviolet ray-curable adhesive 5 does not have a region where the ultraviolet ray does not hit, and the adhesive 5 can be uniformly cured. Further, after the ultraviolet curable adhesive 5 is cured using a screw made of a resin such as polycarbonate, a screw made of aluminum may be used instead of the screw.

(Fifth Step) The lens substrate 4 is brought into contact with the ultraviolet curable adhesive 5 on the light source substrate 2. At this time, the distance between the lens substrate 4 and the light source substrate 2 is increased in advance in consideration of the shrinkage amount of the ultraviolet curable adhesive 5 and the amount required for optimum positioning. (Sixth step) As shown in FIG. 10, ultraviolet rays are emitted from above the lens substrate 4 by the ultraviolet ray irradiation device 11. (Seventh step) As shown in FIG.
Tighten with 2 to adjust to the most collimable spacing.

According to the structure of the optical module manufactured as described above, the positioning of the optical element and the lens as the optical component can be performed with high accuracy, and moreover, between the substrates of both the optical element and the optical component. It is possible to increase the bonding strength of the above, and the reliability can be improved even under high temperature and high humidity, and the size can be reduced. In addition, the variation in the distance between the substrates can be finely adjusted with a screw, and the yield is improved. Also, as in the past,
Since the joining surface is not cleaned and mechanical pre-processing is not required, man-hours can be reduced, leading to cost reduction.

12 and 13 show an optical module according to another embodiment of the present invention, which uses a spherical lens 3b and a microlens array 3c as lenses, respectively.

FIG. 14 shows a laser radar device using the optical module of the present invention. The optical module 15 includes a light emitting module as described above, and a light receiving module using a light receiving element having a structure equivalent to the light emitting element instead of the light emitting element and detecting light intensity. Light is emitted and projected toward the target 16, and the reflected light is received by the light receiving element. The signal processing circuit 17 outputs a light projecting timing signal to the optical module 15 and processes a light receiving signal output from the optical module 15.

FIG. 15 shows an example in which the above laser radar device is mounted on a vehicle. A laser radar device 21 is provided on the front surface of the vehicle 20 to function as an inter-vehicle distance sensor,
Based on the detected information, issue an alarm about obstacles,
The brakes can be applied and steering control can be performed. 16A and 16B are an overall conceptual diagram and a specific configuration diagram of the laser radar device 21 when it is made to function as an inter-vehicle distance sensor. When functioning as an inter-vehicle distance sensor, the projected beam does not spread even if the projected distance becomes long, and it is necessary to maintain the optical power density, but by using the optical module of the present invention, it is possible to respond to it. Moreover, since the bonding strength between the two substrates of the optical module is increased, a device resistant to vibration can be realized.

In FIG. 16, a laser radar device 21 is provided.
Is a light projecting section 22 formed of an optical module having a laser diode LD as a light emitting element, a scanner section 23 for projecting light, and a photodiode as a light receiving element instead of the light emitting element with the same configuration as the light projecting section 22. Light receiving part 24 with PD
And a distance measurement processing unit 25. Light emitted from the light projecting unit 22 and the scanner unit 23 is reflected by the preceding vehicle in front of the vehicle as the reflector 28. The reflected light is received by the light receiving unit 24, and the distance measurement processing unit 25 calculates the distance to the reflector 28 based on the time delay between the light projection and the light reception. The distance information thus obtained is transmitted to the ECU and can be appropriately used for control of traveling steering.

FIG. 17 shows an embodiment of the photoelectric sensor. The photoelectric sensor 31A includes an optical module 32 having a light emitting element 32a and an optical element 32b, a light receiving element 34, and a controller 3.
5, a drive circuit 36 for driving the light emitting element 32a, and a signal processing circuit 37 for processing a signal from the light receiving element 34. The light projected from the light emitting element 32a through the optical element 32b is reflected by the target object 38, the reflected light is received by the light receiving element 34, and the information such as the presence or absence of an object can be detected by the signal processing circuit 37.

FIG. 18 shows an embodiment of the optical sensor device.
The optical sensor device 31B includes an optical scanning device 39 for scanning the light from the optical module 32 and a drive circuit 36b for driving the optical scanning device 39, in addition to the configuration of the photoelectric sensor 31A. . This optical sensor device 31B
According to this, it is possible to detect information such as the presence or absence and the shape of the object 38.

FIG. 19 shows an example in which a code information reading device (bar code reader) is constructed using the optical module of the present invention. The code information reading device 41 includes an optical module 42.
An optical scanning device 43 formed of a polygon mirror or the like for scanning the light from the optical module 42, a light receiving section 44 having a light receiving element for detecting the light intensity, and a signal processing circuit for processing an electric signal output from the light receiving element. The optical beam emitted from the optical module 42 is scanned by the optical scanning device 43 to optically scan an object 48 having code information such as a bar code, a multi-stage bar code, and a matrixed two-dimensional bar code. The reflected light from the object 48 is received by the light receiving unit 4
4 receives the light, and the signal processing circuit 45 reads the code information. As described above, in any of the embodiments, by using the optical modules 32 and 42 of the present invention, it is possible to measure with high accuracy in a wide temperature range.

[0024]

As described above, according to the optical module of the present invention, the elastic body is interposed between the first member holding the optical element and the second member holding the optical component, and the first member is provided. Since the gap between the member and the second member is set by using the gap setting means, the following effects can be obtained. (1) Since the elastic body and the interval setting unit work together, the interval setting unit can finely adjust the variation in the interval between both members, so that the positioning accuracy of both members can be increased and the yield is increased. (2) High reliability can be obtained even in a harsh environment, particularly under high temperature and high humidity, and stable characteristics can be obtained over a wide range of temperature changes. (3) Since the joint surface does not need to be cleaned, the number of steps can be reduced. (4) Since no mechanical pre-processing is required on the joint surface, it leads to cost reduction. (5) The optical module can be downsized. Further, according to the optical module of the present invention, the bonding strength is further improved by using the adhesive as the elastic body. Further, according to the laser radar device of the present invention, it is possible to perform highly accurate measurement even if the target object is at a long distance. Also,
According to the photoelectric sensor, the optical sensor device, or the code information reading device of the present invention, it is possible to highly accurately detect information such as the presence or absence of an object and the shape thereof, or a code such as a barcode.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an optical module whose position is adjusted only by conventional processing accuracy.

FIG. 2 is a sectional view of an optical module whose position is adjusted by the thickness of a conventional adhesive layer.

FIG. 3 is a cross-sectional view of an optical module whose position is adjusted with an adhesive layer and a screw according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of an optical module according to an exemplary embodiment of the present invention in which an adhesive is applied to an adhesive surface on a light source substrate side.

FIG. 5 is a schematic perspective view of the optical module in the state of FIG.

FIG. 6 is a sectional view of an optical module in which a plastic lens and a lens substrate are integrated.

FIG. 7 is a cross-sectional view of the optical module in which the screw and the adhesive are in contact.

FIG. 8 is a cross-sectional view of an optical module in which screw holes are also filled with an adhesive.

FIG. 9 is a sectional view of an optical module using a Fresnel lens.

FIG. 10 is a cross-sectional view of the optical module in a position adjusting process.

FIG. 11 is a cross-sectional view of the optical module in a position adjusting process.

FIG. 12 is a sectional view of an optical module using a spherical lens.

FIG. 13 is a cross-sectional view of an optical module using a microlens array.

FIG. 14 is a block diagram showing an electrical configuration of a laser radar device.

FIG. 15 is a schematic perspective view showing a vehicle equipped with a laser radar device.

FIG. 16 is a diagram showing a specific configuration of a laser radar device.

FIG. 17 is a block diagram showing a configuration of a photoelectric sensor.

FIG. 18 is a block diagram showing a configuration of an optical sensor device.

FIG. 19 is a block diagram showing a configuration of a barcode reader.

[Explanation of symbols]

 1 Semiconductor Laser (Optical Element) 2 Light Source Substrate (First Member) 3 Plano-Convex Aspherical Lens (Optical Component) 4 Lens Part Substrate (Second Member) 5 Ultraviolet Curing Adhesive (Elastic Body) 6 Screw (Interval) Setting means) 20 Vehicle 21 Laser radar device 31A Photoelectric sensor 31B Optical sensor device 32 Optical module 37 Signal processing circuit 41 Code information reading device 42 Optical module 45 Signal processing circuit

Claims (12)

[Claims] 1. An optical module that projects light emitted from an optical element through an optical component, a first member that holds the optical element, a second member that holds the optical component, and An optical module comprising: an elastic body interposed between both members; and an interval setting means for setting an interval between the both members in a state where the elastic body is compressed. 2. The optical module according to claim 1, wherein the interval setting means is a screw. 3. The optical module according to claim 1, wherein the elastic body is an adhesive. 4. The optical element according to claim 1, wherein at least one of the first member and the second member is a light transmissive material, and the elastic body is a photocurable resin. module. 5. The optical element is a light emitting semiconductor element,
The optical component is a lens.
The optical module described in. 6. The optical module according to claim 2, wherein the elastic body has a structure that does not come into contact with the screw. 7. The optical module according to claim 4, wherein the screw is a light transmissive material. 8. The optical module according to claim 1, and a signal processing circuit that processes an electric signal output from a light receiving element that detects light intensity, wherein the optical element of the optical module emits laser light. , The laser beam is projected onto a target object, the reflected light from the target object is received by the light receiving element, and the distance to the target object is measured by the signal processing circuit based on the time delay from light emission to light reception. A laser radar device characterized by the above. 9. A vehicle equipped with the laser radar device according to claim 8. 10. A photoelectric sensor comprising the optical module according to claim 1. 11. An optical module according to claim 1,
An optical scanning device that scans light and a signal processing unit that processes an electric signal output from a light receiving element that detects light intensity are provided, and a light beam emitted from the optical module is scanned by the optical scanning device. An optical sensor device, which illuminates an object, receives light reflected from the object by the light receiving element, and detects information such as the presence or absence and the shape of the object by the signal processing means. 12. The optical module according to claim 1,
An optical scanning device that scans light and a signal processing unit that processes an electric signal output from a light receiving element that detects light intensity are provided, and a light beam emitted from the optical module is scanned by the optical scanning device. A code information reading device which irradiates an object having code information such as a bar code, receives reflected light from the object by the light receiving element, and reads the code information by the signal processing means.