KR20090108310A - Bi-directional optical module using optical fiber and laser range finder using the same - Google Patents

Abstract

PURPOSE: A bidirectional optical module using optical fiber and a laser range finder using the same are provided to reduce the volume of the optical module by decreasing the distance difference between a laser diode and a photo diode based on a reflective filter. CONSTITUTION: A transparent housing cover is combined in an upper side of a body housing(100). A light emitting device and a light receiving device are fixed in the body housing with a preset interval. A reflective surface of a reflective filter(108) is inclined to an output optical axis of the light emitting device and an incidence optical axis of the light receiving device. A condensing lens(107) is arranged between the reflective filter, and the light emitting device and the light receiving device to condense the output light and the incident light has a penetration hole. The optical fiber(105) passes through a part of the condensing lens. Both ends of the optical fiber face the light emitting device and the reflective filter.

Description

Bi-directional optical module using optical fiber and laser distance measuring device using same {BI-DIRECTIONAL OPTICAL MODULE USING OPTICAL FIBER AND LASER RANGE FINDER USING THE SAME}

The present invention relates to a bidirectional optical device, and more particularly, a bidirectional optical module and a laser distance measuring device, in which an emission optical system and an incident optical system are packaged to perform both light emission and light reception in one module. It is about.

In general, laser optical devices (hereinafter, referred to as 'laser space recognition sensors') that scan a laser beam to detect a target or obtain distance information include a bidirectional optical module for emitting and receiving laser light. do. Examples of commercially available laser space recognition sensors include laser range finders (LRFs), time of flight (TOF) cameras, and RF radars.

The representative companies that have commercialized the laser space sensor are Sick AG of Germany and Hokuyo of Japan. In general, the URG-04LX sensor of Japan's Hokuyo Corporation is smaller and lighter than Sick AG's space recognition sensor, but the scan distance is short within 4 meters (m), and the scan speed is low as 10 Hz. Sick AG's space recognition sensor has the disadvantage of large size and heavy weight, but it is widely known that the scan distance can be several tens of meters (m) and the scan speed can be increased up to 20 hertz (Hz).

The spatial recognition sensor using RF or ultrasonic wave is weakly converged and has low spatial resolution, so it is mainly used only for near space recognition, whereas the sensor using laser light source is easy to control the convergence of the beam and the measurement speed. Because of its excellent precision, precision and measurement distance per unit time, it has been applied in various ways in a wide variety of fields requiring high resolution, long distance measurement and high speed measurement.

Examples of publications related to laser space recognition sensors include Korean Patent Publication No. 1997-0048621 (Laser Measuring Device), Korean Patent Publication No. 2001-0015537 (Measuring Head), and Korean Patent Publication No. 1997-0004170 ( Low-cost laser range finder system structure). Such laser spatial recognition sensors have a single wavelength pulse laser in the form of a single or a plurality of arrays to scan laser light in a target direction, receive light reflected by the target with a photo diode, and then emit the light. The distance from the target to the target by calculating the time difference from reflection to reflection.

Since the laser spatial recognition sensors as described above are manufactured in the form of a package in which a laser diode, a photodiode, a condenser lens, and the like are integrated in one module, it is important to design the emission optical system and the incident optical system in a structure capable of miniaturizing the module. In this regard, in order to reduce the distance difference between the laser diode and the photodiode in the bidirectional optical module proposed by Hokuyo Automatic, one peripheral portion of the condenser lens is removed and used as a light receiving path, as shown in FIG. As shown in FIG. 2, a structure is disclosed in which a hole is formed in a central portion of a condenser lens to induce light.

3 and 4 show a schematic configuration of a laser distance measuring apparatus 20 that is currently commercialized. As shown in FIG. 3, the laser distance measuring device 20 includes optical components including a reflective filter 26 in the form of a reflector inside the main body housing 21, and is transparent to the light passing outside the reflective filter 26. The housing cover 28 has a combined shape. In addition, as shown in FIG. 4, the laser distance measuring device 20 includes a driving system support 22, a reflection filter driving coil 23, a reflection filter driving motor 24, and a reflection filter support 25 in the body housing 21. The reflective filter 26, the drive cover 27, and the housing cover 28 are sequentially assembled. Although not shown in the drawing, the body housing 21 includes a laser diode, a photodiode and a condenser lens for transmitting and receiving laser light, and a signal processing unit for signal processing for calculating a distance to the target. .

In the laser distance measuring device 20, an optical path of one optical axis is substantially formed via the reflective filter 26, and as shown in FIG. 5, the reflective filter 26 is formed at a predetermined angle by a drive system. It is operated to scan the laser light by rotating within the measuring range R.

However, the conventional laser distance measuring device 20 has a problem that interference occurs between the incident light and the incident light passing through the condensing lens in the optical system, and there is a problem that a light transmission loss occurs in the process of passing through the condensing lens. Countermeasures are required.

6 illustrates a pigtail type TOCAN laser diode assembly used in a conventional bidirectional optical module for communication. As shown in the figure, the TOCAN laser diode assembly includes a pigtail housing 32 having a rubber cover 31 coupled thereto, a ferruled fiber connected to an output end of the pigtail housing 32, and a pigtail housing 32. It is provided in a structure including a TOCAN laser diode (33) connected to the input terminal.

The present invention was devised in consideration of the above problems, and a bidirectional optical module and a laser using the same, which can prevent a phenomenon of optical interference between the emitted light and the incident light passing through the condenser lens and reduce the light transmission loss caused by the condenser lens. To provide a distance measuring device.

It is another object of the present invention to provide a bidirectional optical module in which an emission optical system and an incident optical system are closely arranged through a structure in which a laser diode or a photodiode is integrated into an optical system through an optical fiber, and a laser distance measuring apparatus using the same.

In order to achieve the above object, the bidirectional optical module according to the present invention includes a main body housing; A light emitting device and a light receiving device fixedly spaced apart from each other in the main body housing; A reflection filter whose reflection surface is inclined with respect to the exiting optical axis of the light emitting element and the incident optical axis of the light receiving element; A condenser lens disposed between the light emitting device, the light receiving device, and the reflective filter to focus the emitted light and the incident light, and a through hole formed in a part of the body; And an optical fiber fitted to pass through the through hole, one end of which is optically aligned with one of the light emitting element and the light receiving element, and the other end of which is optically aligned with the reflective filter.

According to another embodiment of the invention, the body housing; A light emitting device and a light receiving device fixedly spaced apart from each other in the main body housing; A reflection filter whose reflection surfaces are inclined with respect to the exiting optical axis of the light emitting element and the incident optical axis of the light receiving element; A condenser lens disposed between the light emitting element, the light receiving element, and the reflection filter to focus the emitted light and the incident light; And an optical fiber disposed so as to pass outside one edge of the condensing lens, one end of which is optically aligned with one of the light emitting element and the light receiving element, and the other end of which is optically aligned with the reflective filter. A bidirectional optical module is provided.

Preferably, a TOCAN type laser diode may be used as the light emitting device, and a ferrule type optical fiber may be used as the optical fiber.

The bidirectional optical module according to the present invention includes a reinforcing housing made of metal covering the ferrule optical fiber; And a pigtail housing for fixing the reinforcement housing and the TOCAN type laser diode.

The reflection filter may be rotatably installed around a rotation axis parallel to the emission optical axis.

According to another aspect of the present invention, a laser diode assembly which is provided in the bidirectional optical module packaged with the exit optical system and the incident optical system to emit a laser light, Pigtail housing (Pigtail) housing; A laser diode of a TOCAN type coupled to one side of the pigtail housing; A ferrule optical fiber coupled to the other side of the pigtail housing and aligned with the laser diode; And a reinforcing housing which covers the ferrule optical fiber and is fixed to the pigtail housing to support the ferrule optical fiber.

According to another aspect of the invention the body housing; A light emitting device and a light receiving device fixedly spaced apart from each other in the main body housing; And a reflecting filter having a reflecting surface inclined with respect to the output optical axis of the light emitting element and the incident optical axis of the light receiving element, and rotatably installed about a rotation axis parallel to the output optical axis; A condenser lens disposed between the light emitting device, the light receiving device, and the reflective filter to focus the emitted light and the incident light, and a through hole formed in a part of the body; An optical fiber fitted to pass through the through hole, one end of which is optically aligned with one of the light emitting element and the light receiving element, and the other end of which is optical axis aligned with the reflective filter; And obtaining a start signal for the laser light emitted from the laser diode, obtaining a stop signal for the laser light from the photodiode, and calculating a time difference between the start signal and the stop signal. It is provided with a laser distance measuring apparatus comprising a; signal processing unit for calculating the distance to the target.

According to another aspect of the invention the body housing; A light emitting device and a light receiving device fixedly spaced apart from each other in the main body housing; And a reflecting filter having a reflecting surface inclined with respect to the output optical axis of the light emitting element and the incident optical axis of the light receiving element, and rotatably installed about a rotation axis parallel to the output optical axis; A condenser lens disposed between the light emitting element, the light receiving element, and the reflection filter to focus the emitted light and the incident light; An optical fiber disposed to pass outside one edge of the condensing lens, one end of which is optically aligned with one of the light emitting element and the light receiving element, and the other end of which is optically aligned with the reflective filter; And obtaining a start signal for the laser light emitted from the laser diode, obtaining a stop signal for the laser light from the photodiode, and calculating a time difference between the start signal and the stop signal. It is provided with a laser distance measuring apparatus comprising a; signal processing unit for calculating the distance to the target.

According to the present invention, the spot size of the laser light can be maintained at a sufficient size through the optical fiber, and there is an advantage of improving the light transmission efficiency since no light interference or light transmission loss occurs in the condenser lens.

In addition, since the distance difference between the laser diode and the photodiode can be reduced based on the reflection filter, the volume of the optical module can be reduced and the integration degree of the optical component can be improved.

The present invention can be usefully applied to a bidirectional optical module such as a spectrometer, a CD-rom writer, a DVD recorder / player, as well as a distance measuring sensor such as a laser range finder (LRF).

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

7 is a cross-sectional view showing the main configuration of the bidirectional optical module according to an embodiment of the present invention.

Referring to FIG. 7, a bidirectional optical module according to an exemplary embodiment of the present invention may be spaced apart from each other in a main body housing 100 having a predetermined shape in which a housing cover 101 made of a transparent material is coupled to an upper portion of the bidirectional optical module. A light emitting element and a light receiving element fixed to each other, a reflection filter 108 disposed obliquely inclined in the body housing 100 so as to face the light emitting element and the light receiving element, and between the light emitting element and the light receiving element and the reflective filter 108. A condenser lens 107 fixed in the body housing 100 so as to be positioned, and an optical fiber 105 penetrating a portion of the condenser lens 107 and opposite ends thereof to face the light emitting element and the reflective filter 108, respectively. do.

In the present invention, as the light emitting device, a TOCAN type laser diode 104 for generating laser light having a wavelength within the wavelength range from the visible wavelength band to the infrared wavelength band is employed, and the light emitting element is emitted from the laser diode 104. It is preferable that a photodiode 102 for receiving the received light is employed, but various equivalents may be adopted. Hereinafter, the present invention will be described with reference to an example in which a TOCAN type laser diode is used as a light emitting device and a photodiode is used as a light receiving device.

The reflective filter 108 has a substantially reflecting mirror structure, and the reflecting surface formed on one side thereof is disposed obliquely with respect to the exiting optical axis of the laser diode 104 and the incident optical axis of the photodiode 102. In order to scan the laser light, the reflection filter 108 is preferably installed in the main body housing 100 so as to be rotatable about its axis of rotation parallel to the exiting optical axis.

The condenser lens 107 is disposed between the laser diode 104 and the photodiode 102 and the reflection filter 108 to focus the output light toward the target (not shown) through the reflection filter 108, and to the target. The incident light incident through the reflection filter 108 after being reflected by the light is focused on the photodiode 102.

One side of the body of the condenser lens 107 is formed with a through hole (not shown) extending in the thickness direction, the optical fiber 105 is coupled to the through hole.

The optical fiber 105 is inserted through the through hole, one end of which is optically aligned with the laser diode 104, and the other end thereof is aligned with the optical axis of the reflective filter 108. As the optical fiber 105, a ferrule optical fiber is employed, and is coupled to a conventional pigtail housing 103 to align with the TOCAN laser diode 104 to form a pigtail type laser diode assembly. At this time, the laser diode 104 is fixed to one side of the pigtail housing 103 and the optical fiber 105 is coated on the other side to support the optical fiber 105 to maintain a straight shape, preferably made of a metal material 106 ) Is fixed.

Accordingly, the light emitted from the laser diode 104 travels along the optical fiber 105, passes through the condenser lens 107 without refraction, reaches the reflection filter 108, and is then reflected by the reflecting surface to be a target (not shown). (See A), and the light returned by the target after being reflected by the target (see B) is reflected by the reflecting surface of the reflective filter 108 and then focused by the condenser lens 107 to enter the photodiode 102. do. Such laser light emission and light reception processes are repeatedly performed by a predetermined drive system during the operation in which the reflective filter 108 rotates within a measurement angle at a predetermined angle, thereby scanning the laser light.

8 is a main configuration of a bidirectional optical module according to another embodiment of the present invention. In the drawings, the same reference numerals as the above-described embodiments indicate the same components, and thus, detailed descriptions thereof will be omitted.

In the present embodiment, the condenser lens 107 'employs a high-efficiency lens without a through hole, unlike the embodiment described above, and the optical fiber 105 of the pigtail type laser diode assembly is one side of the condenser lens 107'. It is arranged to pass outside the edge.

Accordingly, the light emitted from the laser diode 104 travels along the optical fiber 105, passes through the outside of the condenser lens 107 ′, reaches the reflection filter 108, and is reflected by the reflecting surface to be a target (not shown). The light emitted toward the light source and reflected by the target and then returned is reflected by the reflective surface of the reflective filter 108 and then focused by the condenser lens 107 'and incident on the photodiode 102. Such laser light emission and light reception processes are repeatedly performed by a predetermined drive system during the operation in which the reflective filter 108 rotates within a measurement angle at a predetermined angle, thereby scanning the laser light.

According to another aspect of the present invention there is provided a laser distance measuring device having the bidirectional optical module and a signal processing unit (not shown) as described above. The laser distance measuring device scans the laser light in the same manner as described above, and at the same time acquires a start signal for the laser light emitted from the laser diode 104 using the signal processing unit. After obtaining the stop signal for the laser light from 102, the distance to the target is calculated by calculating the time difference between the start signal and the stop signal.

Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto and will be described below by the person skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of the claims.

The following drawings, which are attached to this specification, illustrate preferred embodiments of the present invention, and together with the detailed description of the present invention serve to further understand the technical spirit of the present invention, the present invention includes matters described in such drawings. It should not be construed as limited to.

1 and 2 are cross-sectional views showing the configuration of a bidirectional optical module according to the prior art.

Figure 3 is a perspective view showing the appearance of a laser distance measuring apparatus according to the prior art.

4 is an exploded perspective view illustrating a part of the configuration of FIG. 3.

FIG. 5 is a perspective view illustrating a measurement range of the laser distance measuring device illustrated in FIG. 3.

6 is a block diagram of a typical pigtail type laser diode assembly.

7 is a cross-sectional view showing the configuration of a bidirectional optical module according to an embodiment of the present invention.

8 is a cross-sectional view showing the configuration of a bidirectional optical module according to another embodiment of the present invention.

<Description of Major Reference Marks in Drawings>

100: main body housing 101: housing cover

102: photodiode 103: pigtail housing

104: laser diode 105: optical fiber

106: reinforcing housing 107,107 ': condenser lens

108: reflection filter

Claims (10)

In the bidirectional optical module packaged with the exit optical system and the incident optical system, Body housing; A light emitting device and a light receiving device fixedly spaced apart from each other in the main body housing; A reflection filter whose reflection surface is inclined with respect to the exiting optical axis of the light emitting element and the incident optical axis of the light receiving element; A condenser lens disposed between the light emitting device, the light receiving device, and the reflective filter to focus the emitted light and the incident light, and a through hole formed in a part of the body; And And an optical fiber fitted to pass through the through hole, one end of which is aligned with one of the light emitting element and the light receiving element, and the other end of which is aligned to face the reflective filter. In the bidirectional optical module packaged with the exit optical system and the incident optical system, Body housing; A light emitting device and a light receiving device fixedly spaced apart from each other in the main body housing; A reflection filter whose reflection surfaces are inclined with respect to the exiting optical axis of the light emitting element and the incident optical axis of the light receiving element; A condenser lens disposed between the light emitting element, the light receiving element, and the reflection filter to focus the emitted light and the incident light; And An optical fiber disposed to pass outside one edge of the condensing lens, one end of which is aligned with one of the light emitting element and the light receiving element, and the other end of which is arranged to face the reflective filter; . The method according to claim 1 or 2, The light emitting device is a laser diode of the TOCAN (Transistor outline CAN) type, The optical fiber is a bidirectional optical module, characterized in that the ferrule (Ferrule) type optical fiber. The method of claim 3, A reinforcing housing made of metal covering the ferrule optical fiber; And And a pigtail housing for fixing the reinforcement housing and a laser diode of the TOCAN type. The method according to claim 1 or 2, The reflection filter is a bidirectional optical module, characterized in that rotatably installed around the axis of rotation parallel to the output optical axis. In the laser diode assembly which is provided in the bidirectional optical module packaged with the exit optical system and the incident optical system, and emits laser light, Pigtail housings; A laser diode of a TOCAN type coupled to one side of the pigtail housing; A ferrule optical fiber coupled to the other side of the pigtail housing and aligned with the laser diode; And And a reinforcing housing which covers the ferrule optical fiber and is fixed to the pigtail housing to support the ferrule optical fiber. Body housing; A light emitting device and a light receiving device fixedly spaced apart from each other in the main body housing; A reflection filter disposed at an inclined surface with respect to an exiting optical axis of the light emitting device and an incident optical axis of the light receiving device, respectively, the reflecting filter being rotatably disposed about a rotation axis parallel to the exiting optical axis; A condenser lens disposed between the light emitting device, the light receiving device, and the reflective filter to focus the emitted light and the incident light, and a through hole formed in a part of the body; An optical fiber fitted to pass through the through hole, one end of which is aligned with one of the light emitting element and the light receiving element, and the other end of which is aligned to face the reflective filter; And Acquire a start signal for the laser light emitted from the laser diode, obtain a stop signal for the laser light from the photodiode, calculate a time difference between the start signal and the stop signal, and then target the target signal. And a signal processing unit calculating a distance to the laser distance measuring apparatus. Body housing; A light emitting device and a light receiving device fixedly spaced apart from each other in the main body housing; A reflection filter disposed at an inclined surface with respect to an exiting optical axis of the light emitting device and an incident optical axis of the light receiving device, respectively, the reflecting filter being rotatably disposed about a rotation axis parallel to the exiting optical axis; A condenser lens disposed between the light emitting element, the light receiving element, and the reflection filter to focus the emitted light and the incident light; An optical fiber disposed to pass outside one edge of the condensing lens, one end of which is aligned with one of the light emitting element and the light receiving element, and the other end of which is arranged to face the reflective filter; And Acquire a start signal for the laser light emitted from the laser diode, obtain a stop signal for the laser light from the photodiode, calculate a time difference between the start signal and the stop signal, and then target the target signal. And a signal processing unit calculating a distance to the laser distance measuring apparatus. The method according to claim 7 or 8, The laser diode is a TOCAN type laser diode, The optical fiber is a laser distance measuring apparatus, characterized in that the ferrule type optical fiber. The method of claim 9, A reinforcing housing made of metal covering the ferrule optical fiber; And Pigtail housing for fixing the reinforcement housing and the laser diode of the TOCAN type; laser distance measuring apparatus further comprises.

Images