Patent Publication Number: US-2019181614-A1

Title: Laser radar device

Description:
FIELD 
     The subject matter relates to a laser radar device, especially relates to a laser radar ranging device based on vertical cavity surface emitting laser (VCSEL). 
     BACKGROUND 
     Laser radar devices can be used for distance detection. Such a laser radar device may include a laser emitter, a detector, and a plurality of lenses. The laser emitter and the detector are usually separated. The lenses are independently manufactured, which can cause performance deviation. Furthermore, mechanical components are required to mount the plurality of lenses during assembly, which is cumbersome and further causes deviation. Thus, improvement in the art is needed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Implementations of the present disclosure will now be described, by way of example only, with reference to the attached figures, wherein: 
         FIG. 1  is a diagram of a laser radar device, in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 2  is an exploded view of the laser radar device of  FIG. 1 . 
         FIG. 3  is a diagram of an optical coupling device included in the laser radar device of  FIG. 2 . 
         FIG. 4  is a cross-sectional view taken along line IV-IV of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the exemplary embodiments described herein. However, it will be understood by those of ordinary skill in the art that the exemplary embodiments described herein can be practiced without these specific details. 
     In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the exemplary embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure. 
     Definitions that apply throughout this disclosure will now be presented. 
     The term “substantially” is defined to be essentially conforming to the particular dimension, shape, or other feature that the term modifies, such that the component need not be exact. For example, “substantially rectangular” means that the object resembles a rectangle, but can have one or more deviations from a true rectangle. 
     The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, assembly, series, and the like. 
     Referring to  FIG. 1  and  FIG. 2 , a laser radar device  100  comprises a printed circuit board  10 , a transmitter  20 , a receiver  30 , an optical coupler  40 , and a processor  50 . 
     The printed circuit board  10  comprises a first surface  12  and a second surface  14 . The first surface  12  and the second surface  14  are opposite sides of the printed circuit board  10 . The first surface  12  is parallel to the second surface  14 . 
     The transmitter  20  and the receiver  30  are mounted on the first surface  12 . The transmitter  20  and the receiver  30  are spaced apart from each other. Both the transmitter  20  and the receiver  30  are electrically connected to the printed circuit board  10 . In the exemplary embodiment, the transmitter  20  is a vertical cavity surface emitting laser (VCSEL) for emitting laser light. The receiver  30  is configured to receive light which is reflected by an object (not shown). 
     Referring to  FIG. 1  and  FIG. 3 , the optical coupler  40  is mounted on the first surface  12 . The optical coupler  40  is a substantially rectangular. The optical coupler  40  comprises a lower surface  41 , an upper surface  42 , a front surface  43 , and a rear surface  44 . The lower surface  41  and the upper surface  42  are opposite and parallel to each other. The front surface  43  and the rear surface  44  are opposite and parallel to each other. The front surface  43  and the rear surface  44  are perpendicularly connected to the lower surface  41  and the upper surface  42 . The lower surface  41  is mounted on the first surface  12 . A first recess  410  is defined in the lower surface  41 . A bottom surface of the first recess  410  is parallel to the lower surface  41  and serves as an incident surface  45  of the optical coupler  40 . A second recess  420  is defined in the upper surface  42 . A bottom surface of the second recess  420  is oblique to the upper surface  42  and serves as a reflective surface  46  of the optical coupler  40 . A third recess  430  is defined in the front surface  43 . A bottom surface of the third recess  430  is parallel to the front surface  43  and serves as an emergent surface  47  of the optical coupler  40 . The emergent surface  47  is corresponding to the incident surface  45 . An angle between the reflective surface  46  and the incident surface  45  is equal to an angle between the reflective surface  46  and the emergent surface  47 . In the exemplary embodiment, the angle between the reflective surface  46  and the incident surface  45  is equal to 45 degrees. A fourth recess  411  is defined in the lower surface  41 . The fourth groove  411  is in air communication with the first groove  410 . In the exemplary embodiment, the fourth groove  411  is a substantially trapezoidal. A depth of the fourth groove  411  is greater than a depth of the first groove  410 . The processor  50  is received in the fourth recess  411 . 
     Two convergent lenses  48  are disposed on the incident surface  45 . One convergent lens  48  diverges the light emitted by the transmitter  20  and the other lens  48  converges and condenses the incoming light reflected by the object. The two convergent lenses  48  have a same shape and size, and are respectively aligned with the transmitter  20  and the receiver  30 . 
     Two collimating lenses  49  are disposed on the emergent surface  47 . One collimating lens  48  is configured to collimate light from the optical coupler  40 , and the other lens  49  collimates light entering into the optical coupler  40 . Two collimating lenses  49  correspond to the two convergent lenses  48 . The two collimating lenses  49  have a same shape and size. 
     In the exemplary embodiment, the convergent lenses  48  and the collimating lenses  49  are integrally formed with the optical coupler  40 . 
     The processor  50  is disposed on the first surface  12  and electrically connected to the printed circuit board  10 . The processor  50  is configured to control the transmitter  20  to emit laser light, and determines the distance between the laser radar device  100  and an object, orientation of the object, and/or size of the object, according to the reflected light from the object. 
     When assembled, the transmitter  20 , the receiver  30 , and the processor  50  are first disposed on the first surface  12 . Then, the optical coupler  40  is disposed on the first surface  12  and covers the transmitter  20  and the receiver  30 . At this time, the incident surface  45  is opposite to the first surface  12 . One convergent lens  48  is aligned with each of the transmitter  20  and the receiver  30 . Then, a peripheral portion of the optical coupler  40 , which faces the first surface  12 , is pasted with adhesive to mount the optical coupler  40  on the first surface  12 , thereby completing the assembly of the laser radar device  100 . 
     Referring to the  FIG. 4 , in operation, the light emitted by the transmitter  20  enters the optical coupler  40  from the incident surface  46 , and the light path the transmitter  20  is changed by the reflective surface  46  and is emitted towards the object through a collimating lens  49 . Then, the light reflected by the object enters the optical coupler  40  from the emergent surface  47 , the light path is changed by the reflection surface  46  and is emitted from the incident surface  45 , and finally the light is transmitted to the receiver  30 . The receiver  30  transmits the optical signal to the processor  50 . 
     In other exemplary embodiments, there may be only one convergent lens  48  and one collimating lens  49 . A transmitter  20  and a receiver  30  can be simultaneously aligned with a convergent lens  48 . 
     The number of the transmitter  20  and the receiver  30  is not limited to one, and the number of the convergent lens  48  or the collimating lens  49  is not limited to two, and may be changed according to need. For example, the transmitter  20  and the receiver  30  can also be four, six, or eight in number, provided that the total number of the transmitters  20  and the receivers  30  is the same as the total number of the convergent lenses  48  and the number of the collimating lenses  49 . 
     In other exemplary embodiments, two positioning pins  120  are disposed on two opposite ends of the first surface  12 . Two positioning holes  412  are defined in the lower surface  41 . The two positioning holes  412  engage with the two positioning pins  120  to position the optical coupler  40  to the printed circuit board  10 , and to align the convergent lens  48  to the transmitter  20  and the receiver  30 . 
     In the exemplary embodiment, the laser radar device  100 , the convergent lens  48 , and the collimating lens  49  are disposed on the optical coupler  40 , and the assembly between the transmitter  20 , the receiver  30  and the convergent lens  48  can be completed in a single installation process, thereby improving installation accuracy and reducing errors during assembly. 
     The embodiments shown and described above are only examples. Many other details are found in the art. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present disclosure have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, especially in matters of shape, size, and arrangement of the parts within the principles of the present disclosure, up to and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the claims.