Patent Publication Number: US-2019178994-A1

Title: Laser distance measuring device

Description:
FIELD 
     The subject matter herein generally relates to a laser distance measuring device. 
     BACKGROUND 
     Laser distance measuring device has been widely used for measuring distance between an object and the device. Nowadays device with a large Field of View and a high measurement accuracy is preferred, thereby a laser distance measuring device with a large Field of View and a high measurement accuracy 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. 
         FIG. 1  is a diagrammatic view of a laser distance measuring device according to an exemplary embodiment of the present disclosure. 
         FIG. 2  is a diagrammatic view of a laser distance measuring unit in accordance with an exemplary embodiment. 
     
    
    
     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 to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the 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 embodiments described herein. The drawings are not necessarily to scale, and the proportions of certain parts may be exaggerated to illustrate details and features of the present disclosure better. The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings, in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.” 
     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, group, series, and the like. The term “about” when utilized, means “not only includes the numerical value, but also includes numbers closest to the numerical value”. 
       FIG. 1  illustrates an exemplary embodiment of a laser distance measuring device  100 . The laser distance measuring device  100  is configured to measure a distance between the laser distance measuring device  100  and an object  200 . 
     The laser distance measuring device  100  includes a plurality of substrates  11 . The plurality of substrates  11  are arranged divergently, in other words, the extension surfaces to the reverse of each of the plurality of substrates  11  are convergent. Each of the plurality of substrates  11  includes a first surface  111 , and a second surface  112  opposite to the first surface  111 . The first surfaces  111  of the plurality of substrates  11  face roughly the same direction. 
     Referring to  FIG. 2 , a laser diode  12 , a photo diode  13 , and a lens module  14  are mounted to the first surface  111  of each of the plurality of substrates  11  to form a laser distance measuring unit  10 . The laser diode  12  and the photo diode  13  are located at a side of the lens module  14  away from the object  200 . The laser diode  12  is configured to emit lasers to the object  200 . The photo diode  13  is configured to receive reflections from the object  200 . The lens module  14  is configured to focus the lasers emitted by the laser diode  12  onto the object  200 . The lens module  14  is also configured to focus the lasers reflected by the object  200 , to ensure more lasers irradiate to the photo diode  13 . 
     The plurality of substrates  11  being arranged in a divergent form improves Field of View (FOV) of the laser distance measuring device  100 , thereby improve accuracy of the distance measuring result. 
     In at least one exemplary embodiment, inclined angles of each two adjacent substrates  11  are equal. In other exemplary embodiment, the inclined angles of each two adjacent substrates  11  are not equal. 
     In at least one exemplary embodiment, the substrate  11  is a circuit board. The laser diode  12  and the photo diode  13  mounted on the circuit board are electrically connected with the circuit board. 
     In at least one exemplary embodiment, the laser diode  12  is an edge-emitting laser diode. An emitting surface of the edge-emitting laser diode faces towards the lens module  14  and is perpendicular to the substrate  11 . 
     The lens module  14  includes at least one optical lens  141 . Each optical lens  141  includes a collimating lens portion  1411 , and a focusing lens portion  1412 . The collimating lens portion  1411  faces towards the laser diode  12 . The focusing lens portion  1412  faces towards the photo diode  13 . The collimating lens portion  1411  is configured to focus the lasers emitted by the laser diode  12 , to ensure greater irradiation of the object  200 . The focusing lens portion  1412  is configured to focus the laser reflections, to ensure more complete irradiation of the photo diode  13 . 
     In at least one exemplary embodiment, the collimating lens portion  1411  is integrally formed with the focusing lens portion  1412 . In other exemplary embodiment, the collimating lens portion  1411  is separated from the focusing lens portion  1412 . 
     When the lens module  14  includes two or more optical lenses  141 , the two or more optical lenses  141  are arranged in a direction from the laser diode  12  and the photo diode  13  towards the object  200 , and the collimating lens portions  1411  of the two or more optical lenses  141  are arranged in a line. The focusing lens portions  1412  of the two or more optical lenses  141  are arranged in a line. 
     The optical lens  141  may be made of glass or plastic. 
     A light propagation path is that lasers are emitted out from the laser diode  12 , pass through the collimating lens portion  1411 , irradiate the object  200  and be reflected therefrom. The reflected lasers pass through the focusing lens portion  1412 , and are finally received by the photo diode  13 . 
     The laser distance measuring device  100  further includes a signal processing module (not shown). The signal processing module is electrically connected with the laser diode  12  and the photo diode  13  of each laser distance measuring unit  10 . The signal processing module can record the process of the laser diode  12  emitting laser and the process of the photo diode  13  receiving reflected laser. A total time of flight (TOF) t n  of the laser from the laser diode  12  to the photo diode  13  is thus known. A distance L n  between the laser distance measuring unit  10  and the object  200  can be calculated by a formula L n =ct n /2, where c represents the speed of light, and n represents the total number of the laser distance measuring unit  10 . A distance L between a laser distance measuring device  100  and the object  200  can be calculated by a formula L=(L 1 +L 2 + . . . +L n )/n. 
     The laser distance measuring device  100  further includes a motor  20 . An end of each of the plurality of substrates  11  is mounted on the motor  20 . The plurality of substrates  11  diverge along a direction away from the motor  20 . 
     Referring to  FIG. 1 , an X-Y-Z coordinate system is built. X-axis is in a horizontal direction, Z-axis is in an upwards direction perpendicular to the X-axis, and Y-axis is in a direction perpendicular to the X-axis and the Z-axis. The motor  20  can drives the plurality of substrates  11  to revolve around the X-axis, so the substrates  11  in effect move back and forth along the Y-axis and up and down along the Z-axis. Thus measuring angles of the laser distance measuring device  100  can be adjusted. 
     In at least one exemplary embodiment, the motor  20  can drive the plurality of substrates  11  to periodically revolve, to achieve an effect of laser scanning from the Y and Z axes which improves accuracy of the measuring operation. 
     It is to be understood, even though information and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the present embodiments, the disclosure is illustrative only; changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the present embodiments to the full extent indicated by the plain meaning of the terms in which the appended claims are expressed.