Patent Publication Number: US-2015077998-A1

Title: Flexible led light string

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a flexible LED light string, and more particularly to a flexible LED light string that can be configured to any particular shape as required and can be easily and conveniently connected to other light strings of the same configuration. 
     2. Description of the Prior Art 
     An LED-based decorative light string is commonly seen in the market nowadays. Particularly, a flexible LED light string made of soft material is very preferable to consumers because it can be configured to any particular shape or wound around objects for decoration purposes. 
     Most of the manufacturers of the flexible LED light strings will provide multiple types of products with different fixed lengths. The fixed-length LED light string may not be practical for all occasions or purposes. Thus, a new type of LED light string connectable in series is launched for consumers. The consumers can buy multiple LED light strings and form a lengthened light string by sequentially connecting these light strings. 
     However, linking structures of the connectable LED light strings are inconvenient to users for quickly connecting the LED light strings. 
     The present invention thus develops a novel flexible LED light string to mitigate or solve the problems mentioned above. 
     SUMMARY OF THE INVENTION 
     The main objective of the present invention is to provide a flexible LED light string that allows users to connect multiple light strips to form a decorative light string without using any hand tools. 
     The flexible LED light string comprises a power control assembly and at least one light strip. The power control assembly comprises a plug, a power converter connected to the plug and outputting a DC voltage; and a main connector connected to the power converter for transmitting the DC voltage. The at least one light strip each comprises a body, a front connector assembled to a first end of the body and detachably screwed to the main connector of the power control assembly, and a rear connector assembled to a second end of the body for screwing to another subsequent light strip. 
     According to the present invention, the front connector of the at least one light strip is screwed to the main connector of the power control assembly for receiving the DC voltage. The rear connector of the at least one light strip is proved for screwing to another light strip sequentially connected, whereby a user can easily form a decorative light string of a required length. 
     Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an AC flexible LED light string with a control box of the present invention; 
         FIG. 2  is an exploded perspective view of the AC flexible LED light string of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of a male connector assembled with a female connector of the flexible LED light string of the present invention; 
         FIG. 4  shows an AC flexible LED light string without a control box of the present invention; 
         FIG. 5  shows a DC flexible LED light string with a control box of the present invention; 
         FIG. 6  shows a DC flexible LED light string without a control box of the present invention; 
         FIG. 7  shows a circuit diagram of the DC flexible LED light string operated in a normally-lighting mode of the present invention; 
         FIG. 8  shows a circuit diagram of the AC flexible LED light string operated in a normally-lighting mode of the present invention; and 
         FIG. 9  shows a circuit diagram of the AC flexible LED light string operated in a self-flashing mode of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIGS. 1 and 2 , a first embodiment of a flexible LED light string of the present invention comprises a power control assembly  10  and at least one light strip  20 . 
     The power control assembly  10  includes a power converter  11 , a control box  12 , a plug  13  and a main connector  14 . The power converter  11  converts an AC voltage received through the plug  13  to a DC voltage for driving LEDs. The converted DC voltage may be either a half wave DC voltage or a full wave DC voltage. The control box  12  is connected between the power converter  11  and the main connector  14 . 
     The control box  12  may optionally include at least one control button  121 . The control box  12  without the control button  121  may have a pre-stored control program for generating control commands to drive the at least one light strip  20  and generate different default lighting effects. Alternatively, the control box  12  with the control button  121  allows a user to select and change lighting effects by operating the control button  121 . The control box  12  may further include a wireless receiver for receiving an external control signal output from an external lighting controller. According to the external control signal received, the control box  12  also generates the control commands to drive the at least one light strip  20  for having the lighting effects by demand. 
     The control box  12  comprises a top shell having a top opening, a bottom shell having a bottom opening and assembled to the top shell, a control circuit board mounted between the top shell and the bottom shell. A waterproof rubber ring may be mounted around edges of the top opening and the bottom opening to improve waterproof effect. 
     The main connector  14  is connected to an output of the control box  12  and is provided to connect to the at least one light strip  20 . The DC voltage and the control commands from the control box  12  are transmitted to the at least one light strip  20  through the main connector  14 . The main connector  14  has a threaded outer surface and two terminal holes  141 . 
     The at least one light strip  20  each comprises a body  21  having two ends, a front connector  22  and a rear connector  23 . The body  21  has a flexible circuit board, multiple LEDs mounted on the flexible circuit board, and a light-pervious protection tube mounted around the flexible circuit board. 
     The front connector  22  has a first end and a second end. With further reference to  FIG. 3 , the first end of the front connector  22  is assembled to one end of the body  21 , and the second end of the front connector  22  is configured as a male connector with two signal terminals  221  for inserting into and being electrically connected the terminal holes  141 . After the insertion of the signal terminals  221  to the terminal holes  141 , a fixing nut  24  mounted around the front connector  22  can be correspondingly screwed with the main connector  14  by a threaded inner surface formed in the fixing nut  24  to enhance the connection between the body  21  and the main connector  14 . A waterproof washer  27  may be provided between the front connector  22  and the main connector  14  to increase sealing effect. 
     The rear connector  23  is assembled to the other end of the body  21  for connecting to another light strip  20 , thereby forming a complete light string with a required length by the multiple light strips  20  connected sequentially. In this embodiment, the rear connector  23  has a configuration the same as the main connector  14 . The rear connector  23  has a first end and a second end, wherein the first end is assembled to the other end of the body  21 . The second end of the rear connector  23  is configured as a female connector with a threaded outer surface and two terminal holes for receiving the signal terminals  221  of a subsequently connected light strip  20 . 
     When multiple light strips  20  are connected in series, a sealing lid  25  can be assembled to the rear connector  23  of the last light strip  20  for waterproof purpose. The sealing lid  25  has a threaded inner surface for correspondingly screwing with the threaded outer surface of the rear connector  23 . A waterproof washer  26  may be inserted between the sealing lid  25  and the rear connector  23 . 
     With reference to  FIG. 4 , the second preferred embodiment is configured as an AC flexible LED light string without the control box. The power converter  11  and the main connector  14  are formed integrally by injection modeling process. The power control assembly  10  does not need a control box. The power converter  11  converts the AC voltage to the DC voltage for driving the LEDs in the at least one flexible light strip  20 . 
     With reference to  FIG. 5 , the third preferred embodiment is configured as a DC flexible LED light string with a control box. The power converter  11  and the plug  13  are integrated as a DC power plug  15 . A voltage output from the DC power plug  15  is a DC voltage capable of driving the LEDs. 
     With reference to  FIG. 6 , the fourth preferred embodiment is configured as a DC flexible LED light string without a control box. The power converter  11  and the plug  13  are integrated as a DC power plug  15 . A voltage output from the DC power plug  15  is a DC voltage capable of driving the LEDs. 
     The at least one light strip  20  can work in different operating modes such as a normally-lighting mode, a self-flashing mode, a self-color-changing mode or a controllable lighting mode. The normally-lighting mode, the self-color-changing mode, self-flashing mode are preferably implemented by the embodiments of  FIGS. 4 and 6 . The controlled lighting mode is preferably implemented by the embodiments of  FIGS. 1 ,  2  and  5 . The operating modes are introduced hereinafter. 
     Normally-lighting mode: The body  21  uses the LEDs of the same color or different colors as lighting elements and all the LEDs are always turned on. 
     Self-color-changing mode: Each of the LEDs mounted on the body is composed of a control chip and multiple LED chips of primary colors R, G and B, wherein each LED chip has  256  illumination gray levels. The control chip automatically controls the LED chips to generate and mix primary colors to obtain various lighting colors. 
     Self-flashing mode: Each of the LEDs mounted on the body is composed of a control chip and multiple LED chips of the same color or different primary colors R, G and B. The control chip will automatically control the LEDs to be alternately turned on or off for a pre-default time. Therefore, the LEDs will generate flashing or dynamic effects. 
     Controllable lighting mode: This mode is similar to the normally-lighting mode, wherein the multiple LEDs on the body  21  are divided into multiple groups. The control box  21  outputs control commands to turn on or off each group. 
     With reference to  FIG. 7 , the AC flexible LED light string operated in the normally-lighting mode can be implemented by this circuit diagram. The LEDs on the at least one light strip  20  are connected in series to form multiple branches, and all the branches are connected in parallel. The power control assembly  10  provides the DV voltage 12V to activate the LEDs. 
     With reference to  FIG. 8 , this circuit diagram is directed to the AC flexible LED light string of  FIG. 4 . The power control assembly  10  converts the AC voltage to a half wave DC voltage for driving the LEDs. 
     With reference to  FIG. 9 , this circuit diagram is directed to the AC flexible LED light string operated in the self-flashing mode or the self-color-changing mode. The power converter  11  comprises a full bridge rectifier to convert the AC voltage received to a full wave DC voltage for driving the LEDs. 
     Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.