Abstract:
A laser marking device including an oscillating mechanism that enables the laser beams emitted from the device to be emitted in either a constant state or in a pulsed state to enhance the visibility of the laser beam in various lighting conditions. The oscillating mechanism modulates the power supplied by the power source into either a constant state or a pulsed state in order to send the power in that state to the laser generator, which consequently emits a laser beam in either a constant or pulsed state. In bright light conditions in which the beam is not readily visible, the beam can be emitted in a pulsed state to be sensed by a separate detector capable of detecting the pulsed beam from the device. The detector provides an indication to the operator of the position of the beam relative to the detector such that the operator can readily determine the location of the beam.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority from Chinese Patent Application Publication No. 200520072421.1, filed Jun. 8, 2005. 
   FIELD OF THE INVENTION 
   The present invention relates generally to laser levels, and more particularly to a laser level including a switch operable to change the mode of operation of the laser generator from a constant beam output to a pulsed beam output. 
   BACKGROUND OF THE INVENTION 
   At present, a large number of line laser products i.e. laser markers or levels, are used in the fields of construction and home remodeling. As a tool used to generate a horizontal base line and vertical base line, laser markers of this type are widely applied in construction fieldwork as a result of their ability to generate a bright line, which is both easily visible and affords higher precision than other measuring or marking devices. Many applications of laser markers of this type use a laser sensor or detector, which typically senses the presence of the beam output by the laser marker and provides a signal (typically an audible and/or a visual signal) in response to detection of the laser beam. 
   With known laser markers, the emitted laser line power signal is constant, which makes it difficult to observe the laser line over even a short distance with the naked eye, especially in bright sunlight conditions. In addition, bright sunlight conditions can prevent the laser sensor or detector from sensing the laser beam emitted by the laser marker. Thus, in actual application, a stronger power laser generator is required to enhance the brightness of the laser line such that it is more capable of being observed or sensed when in operation. However, this also causes an increase in the cost of constructing and using the marker. Further, even if a stronger power laser generator is used, it can still be difficult to observe the laser line with the naked eye in bright sunlight, or to sense the laser line with the sensor, unless the observer or sensor is located a very short distance from the marker. Therefore, increasing the power of the laser generator cannot rectify the problems with line visibility or sensing in markers of this type. 
   SUMMARY OF THE INVENTION 
   It is a primary aspect of the present invention to provide a laser marker device that can switch the mode of operation of the device according to the surrounding light conditions in which the device is to be used. To achieve this purpose, the laser marker device includes a laser driving circuit, and a laser irradiating circuit that is connected with the driving power source output end of the laser driving circuit. The laser irradiating circuit also includes a control circuit and an oscillating circuit that can modulate power signals coming from the control circuit. The control circuit of the present invention can take a variety of different forms, e.g., the power source switch, or a D trigger, or two triodes, with each form having a simple structure and correspondingly low cost. The control signal output end of the control circuit is connected with the control signal input end of the oscillating circuit, and the oscillating signal output end of the oscillating circuit is connected with the oscillating signal input end of the laser driving circuit. In this manner, the mode of operation of the laser driving circuit is switchable between a low electronic level, constant output state and a high electronic level, pulsed output state according to the signals transmitted from the oscillating circuit. Using this configuration, the laser marking device of present invention allows the laser signals to be switched in either a low illumination environment, e.g., indoors, or in a bright sunlight environment, such that only a lower power laser generator is required for the device to be capable of producing a visible laser line in both types of environments, which saves electric power and reduces the cost for the device. 
   According to another aspect of the present invention, the laser marker includes an external switch on the housing for the maker device. The switch is operable to select between a first position in which the output of the device is selected to be a constant output, and a second position in which the output of the device is selected to be a pulsed output. 
   Numerous other aspects, features and advantages of the present invention will be made apparent from the following detailed description taken together with the drawing figures. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings illustrate the best mode currently contemplated of practicing the present invention. 
     In the drawings: 
       FIG. 1  is an isometric view of a laser marking device constructed according to the present invention; 
       FIG. 2  is an isometric view of the laser marking device of  FIG. 1  from another angle; 
       FIG. 3  is a schematic view of the operation of the laser marking device of  FIG. 1 ; 
       FIG. 4  is an isometric view of a sensor or detector and associated handle used with the device of  FIG. 1 ; 
       FIG. 5  is a front elevation view of the sensor or detector of  FIG. 4 ; 
       FIG. 6  schematic view of the electronic circuit of the laser marking device of  FIG. 1 ; 
       FIG. 7  is a schematic view of a first embodiment of the control circuit portion of the electronic circuit of  FIG. 6 ; 
       FIG. 8  is a schematic view of a second embodiment of the control circuit portion of  FIG. 6 ; and 
       FIG. 9  is a schematic view of a third embodiment of the control circuit portion of  FIG. 7 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   With reference now to the drawing figures in which like reference numerals designate like parts throughout the disclosure, a laser marking device constructed according to the present invention is indicated generally at  10  in  FIG. 1 . The device  10  includes a housing  12  that has an upper portion  14 , a middle portion  16  and a lower portion  18 . 
   The lower portion  18  is separated from the middle portion  16  by a rotatable angle dial  20 . The angle dial  20  enables the middle portion  16  to be rotated with respect to the lower portion  18  in order to enable a user of the device  10  to direct the beams from the device  10  at a desired angle with regard to the target, as indicated by the angle marker  21  on the device  10 . The rotation of the middle portion  16  can be accomplished by simply grasping and moving the middle portion  16  relative to the lower portion  18 , or by using one of a pair of fine adjusting screws  22  extending outwardly from the lower portion  18 . 
   The lower portion  18  also is connectable to a tripod base  24  in order to support the device  10  level over an uneven surface (not shown). The tripod  24  includes a connector  26  that functions to releasably engage the tripod  24  to the lower portion  18  of the device  10 . The tripod  24  also includes three individually adjustable legs  28  extending outwardly from the tripod  24 . Each leg  28  is connected by a pivot pin  30  in order to enable each leg  28  to pivot with respect to the tripod  24 . Also, each leg  28  includes an adjustment screw  32  that can be rotated to extend or shorten the leg  28  when leveling the device  10 . After the tripod  24  has been adjusted to level the device  10  as indicated by one or more bubble levels (not shown) disposed on the device  10 , a locking staff  34  can be engaged to secure the tripod  24  in the adjusted position, such the tripod  24  is locked in that position. When it is desired to readjust the tripod  24  and re-level the device  10 , the locking staff  34  can be unlocked, such that the tripod  24  and the legs  28  can again be adjusted. 
   The upper portion  14  is generally dome shaped, and includes a number of windows  36 ,  38  and  40 . The upper portion  14  encloses a laser generator (not shown) that, when operated, generates a laser beam (not shown). The generator is disposed within the upper portion  14  on a self-leveling platform (not shown) that enables the generator to continually generate a level laser beam. The beam from the generator passes through one or more prisms (not shown) disposed adjacent the laser generator to split the beam into a number of reference beams or lines  42 - 46  that pass through the windows  36 - 40  in the upper portion  14 , as best shown in  FIG. 3 . The window  36  is disposed along a vertical centerline of the device  10  and can emit a laser beam to form a first vertical reference line  42 . The windows  38  are disposed on opposite sides of the window  36 , each oriented approximately ninety (90) degrees with respect to the window  36  and directly opposite one another, and each emits a laser beam to form a second vertical line  44 . The windows  40  are disposed in a generally horizontal plane and are located between the window  36  and each of the windows  38 . The windows  40  emit a laser beam that forms a horizontal line  46  that intersects both of the vertical reference lines  42 , 44 . 
   Opposite the window  36 , the upper portion  14  includes an operating panel  48 . The operating panel  48  includes a number of buttons  50 - 54  that are used to activate and deactivate the reference lines  42 - 46 , respectively. The panel  48  also includes a button  56  that is used to switch the mode of operation of the laser generator between a constant mode and a pulsed mode, in a manner to be described. 
   The middle portion  16  houses the operating components of the device  10  that are connected to the laser generator. The middle portion  16  includes a handle  57  on one side that can be used to grasp and move the device  10  where desired. Opposite the handle  57 , the middle portion  16  includes a battery housing  58  with a removable cover  60  that can hold a number of batteries (not shown) to provide power to the device  10 . The middle portion  16  also includes a DC outlet  62  opposite the battery housing  58  that can be used as an alternative power supply for the device  10 . The power supply for the device  10 , whether supplied by the batteries or the DC power, is selectively connected to the laser generator by the operation of a locking knob  64  disposed on the middle portion  16 . The locking knob  64  can be rotated on the middle portion to supply power to the laser generator and to unlock the self-leveling platform on which the generator is disposed. When the knob  64  is rotated back to the locked position, the platform is locked in an immovable position, and the power to the laser generator is interrupted. 
   In conditions in which it is difficult to view the lines  42 - 46 , and particularly when the laser generator is operated in the pulsed mode, the device  10  can be used with a sensor or detector  66 . The detector  66 , as best shown in  FIGS. 4 and 5 , includes a housing  68  with a front panel  70  and a rear panel  72 . The rear panel  72  includes a battery housing  74  for holding a battery (not shown) and a threaded bore  76 . The bore  76  is adapted to receive and engage a bolt  78  disposed in one end of a handle  80 . The engagement of the bolt  78  within the bore  76  enables the handle  80  to be secured to the housing  68 . The front panel  70  includes a detection screen  82  and an indicator screen  84 . The detector screen  82  can sense the constant or pulsed laser beam emitted from the laser generator. Based on the portion of the detector screen  82  that senses the beam, the indicator screen  84  will illustrate whether the beam is below, at or above a centerline of the detector  66 . When the detector  66  is operated with the handle  80 , the detector  66  can also be used to determine whether the beam is to the left or right of a centerline of the detector  66 . 
   Referring now to  FIG. 6 , the internal workings of the laser marking device  10  are schematically illustrated. Particularly, the device  10  includes a control circuit  100 , an oscillating circuit  200  that can produce modulation signals, a laser driving circuit  300  and a laser irradiating circuit  400  that is connected with a driving power source output end  302  of the laser driving circuit  300 . 
   Looking now at  FIGS. 6 and 7 , the control circuit  100  in a first embodiment is constructed as a power source switch K 1 . Leg or output end  102  of the power source switch K 1  is the control signal output end of said control circuit  100 , leg  104  of the power source switch K 1  is connected to the ground  105 , and leg  106  is connected to the power source  108 , i.e., the battery housing  58  or the DC outlet  62 . 
   In a second embodiment shown in  FIG. 8 , the control circuit  100 ′ can also comprise a button-igniting circuit  110  and a D igniter or trigger UA. The second embodiment of the control circuit  100 ′ comprises the button-trigger circuit and an trigger UA, and the control signal output end of the button- trigger circuit is connected with the control signal input end of D trigger UA, and the output end of the D trigger UA is the control signal output end of the control circuit. More specifically, the button-igniting circuit  110  comprises a button K 2 , a pair of resistors R 1  and R 2  and a pair of capacitors C 1  and C 2 . When the button K 2  is depressed, the capacitor C 1  can filter the waves from the power source and eliminate dithering. Further, the end  112  of the D igniter UA functions as the control signal output end  102  of the control circuit  110 . 
   Additionally, in a third embodiment of the control circuit  100 ″ shown in  FIG. 9 , the control circuit  100 ″ can comprise a button K 3 , two triodes Q 1  and Q 2 , four resistors R 1  and R 2  and R 3  and R 4 , and two capacitors C 1  and C 2 . In this embodiment, the emitting electrode of the triode Q 1  is connected with the power source  108 , and the resistor R 1  is connected in parallel between the collector electrode and the base electrode of the triode Q 1 . The resistor R 2  is serially connected between the collector electrode and the base electrode of the triode Q 1 , and the emitting electrode of the triode Q 2  is connected to the ground  105 . The capacitor C 2  is connected in parallel between the base electrode and the emitting electrode of the triode Q 2 , and the collector electrode of the triode Q 2  is serially connected with the resistor R 3  and then connected with the base electrode of the triode Q 1 . Further, one end of the button K 3  is connected with the base electrode of the triode Q 2  and the other end of the button K 3  is serially connected with the capacitor C 1  and then the ground  105 . Also, one end of the resistor R 4  is connected with the collector electrode of the triode Q 2  and the other end is serially connected with the capacitor C 1 . The collector electrode of the triode Q 1  is the control signal output end  102  of this embodiment of the control circuit  100 ″. 
   Looking again at  FIG. 6 , between the control circuit  100  and the oscillating circuit  200 , the device  10  includes a commutation diode D, a wave filtered capacitor C 3  and resistors R 5 , R 6 , R 7 . The control signal output end  102  of the control circuit  100  is connected with the cathode of the commutation diode D, and the anode of the commutation diode D is connected with the control signal input end  202  of the oscillating circuit  200 . The pulling resistor R 5  is also connected with the control signal input end  202  of the oscillating circuit  200 . The resistors R 6  and R 7  are serially connected between the ground  105  and the power source  108 , and their joint  204  is connected with reference voltage end  206  of the oscillating circuit  200 . 
   The oscillating signal output end  208  of the oscillating circuit  200  is connected with the oscillating signal input end  302  of the laser driving circuit  300 . Further, the resistor R 8 , the capacitor C 4  and the constant voltage diode W form a reference power source circuit  400  that is peripheral equipment for the laser driving circuit  300 . 
   The laser irradiating circuit  400  is constructed from a laser diode  402 , a resistor R 9  and a capacitor CS. The laser irradiating circuit  400  is configured to work in either a constant laser line power state or a pulsed laser line power state. More particularly, according to the constant-voltage signals transmitted from the oscillating circuit  200 , it is possible for the laser driving circuit  300  to drive or supply power to the laser irradiating circuit  400  in a constant laser line power state and provide a constantly irradiated laser line. Additionally, according to the modulation signals that can be transmitted from the oscillating circuit  200  it is also possible to supply power to the laser irradiating circuit  400  in a pulsed laser line power pulse state and provide a modulated irradiated laser line. 
   Therefore, when the laser marking device  10  of the present invention is utilized in low-light conditions, e.g. when used indoors, the user can select the electromotive force of the control signal output end  102  of the control circuit  100  to be set at low electronic level, which consequently makes the electromotive force of the oscillating signal output end  202  of the oscillating circuit  200  stay constant, and correspondingly drive the laser irradiating circuit  400  in a constant power state and provide a constant laser line, such that the user can observe the position of the laser line or lines with the naked eye. Alternatively, when the laser marking device  10  of the present invention is utilized in highly illuminated surroundings, e.g., outdoors in bright sunlight conditions, the user can keep the electromotive force of the control signal output end  102  of the control circuit  100  at a high electronic level, which can make the oscillating signal output end  202  of the oscillating circuit  200  transmit a modulated, pulsed signal. According to this modulated, pulsed signal, the laser irradiating circuit  300  can be driven in a pulsed power state to provide a pulsed laser line, the particular location of which can be observed via the line laser detector  66 . 
   Various alternatives are contemplated as being within the scope of the following claims, particularly pointing out and distinctly claiming the subject matter regarded as the invention.