Patent Description:
With a continuous development of light emitting diode technology, the research on LED street lamps has made a breakthrough progress. The current LED street lamps are almost direct current (DC) droved, that is, a mature switching power supply technology is used to turn the alternating current (AC) into DC to drive the LED filament. Related prior art to the manufacturing of related filaments can be found in <CIT>, <CIT>, <CIT>, and <CIT>.

Currently, DC driving has become a mainstream driving method since it can provide stable current for LED. However, the development of DC driving may be restricted by the bottlenecks of using life and cost. Simultaneously, it is very complicated to manufacture a DC droved filament, which further raises the cost.

The present disclosure is to provide a method for manufacturing light emitting diode filament, which aims to solve the problem of complicated manufacturing process and high cost for the filament.

In order to achieve the above aim, the present disclosure provides a method for manufacturing an LED filament, according to claim <NUM>, and the method includes the following operations S1 to S4. Operation S1, a plurality of metal sheets are provided and arranged at least two rows in parallel, each metal sheet at one row has one end extending to the corresponding metal sheet at the other row, and the other ends of each of the metal sheets connect with each other to form a positioning portion; operation S2, a plurality of brackets are provided, and each bracket is located between two corresponding metal sheets and fixedly connected to the two metal sheets; operation S3, a plurality of LED chips are provided and attached to each of the brackets, and the LED chips are electrically connected to the metal sheets by conducting wire; or, each bracket is prefabricated with conducting strip, and the LED chips are attached to the bracket and electrically connected to the metal sheets by the conducting strip; operation S4, each bracket, the LED chips defined on the bracket, the conducting strip or the conducting wire defined on the bracket, and the joints of the bracket and the metal sheets are all cladded using packaging material to form an encapsulation layer, and the encapsulation layer, the bracket, the LED chips, the conducting strip or conducting wire, and the connected two metal sheets cooperatively form an LED filament.

In some embodiments, the method for manufacturing LED filament further includes operation S5, which cuts off the metal sheet at a position located between the positioning portion and the joint of the bracket and the metal sheet to obtain separate LED filaments.

In some embodiments, the positioning portion is defined with a plurality of positioning through holes.

In some embodiments, the plurality of positioning through holes are corresponding to each of the brackets.

According to the invention, each metal sheet defines a clamping part for clamping the bracket.

In some embodiments, the clamping part includes a pair of clamping pieces facing and spaced from each other, the pair of clamping pieces are respectively bent and extended from opposite two sides of the metal sheet, the pair of clamping pieces and the metal sheet cooperatively form a receiving cavity, and the end of the bracket is received in the receiving cavity.

In some embodiments, each of the metal sheets in one row is defined with a marking hole.

In some embodiments, in the operation S5, the metal sheet is cut off at the position located between the positioning through hole and the marking hole to obtain the LED filament.

In the invention, each bracket is attached with a rectifier module, and the rectifier module is defined at an end of the bracket closing to the metal sheet.

In some embodiments, the packaging material includes silicone, rubber, or resin.

In some embodiments, the bracket is made of ceramic or glass.

According to the present disclosure, the method for manufacturing LED filament can produce LED filament groups in batches, which simples the manufacturing process and reduces the cost. Further, the encapsulation layer may completely isolate the LED chips and the brackets from air, so that oxidation of the LED chips and the brackets may be avoided, and a good environment is provided for the LED chips to run well in a confined space. As such, the using life of the LED filament is also greatly improved.

To clearly illustrate the technical solutions that are reflected in various embodiments according to this disclosure, the accompanying drawings intended for the description of the embodiments herein will now be briefly described. It is evident that the accompanying drawings listed in the following description show merely some embodiments according to this disclosure, and that those having ordinary skill in the art will be able to obtain other drawings based on the arrangements shown in these drawings without making inventive efforts.

The technical solutions of the embodiments of the present disclosure will be clearly and completely described in the following with reference to the accompanying drawings.

It is understood that, reference to "embodiment" herein means that a particular feature, structure, or characteristic described may be included in at least one embodiment of the disclosure. The appearances of "embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they independent or alternative embodiments that are mutually exclusive with other embodiments. It is clearly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

Please referring to <FIG>, the method for manufacturing an LED filament according to the present disclosure includes the following operations.

Operation S1, a plurality of metal sheets are provided and arranged at least two rows in parallel, each metal sheet <NUM> at one row has one end extending to the corresponding metal sheet at the other row, and the other ends of each of the metal sheets connect with each other to form a positioning portion.

Specifically, please referring to <FIG>, in one embodiment, two rows of metal sheet <NUM> are prepared. The metal sheet <NUM> may be made of metal with good conductive properties. The metal sheet <NUM> may be obtained by dividing metal strips made in rolls into reasonable length, such as <NUM> millimeters or <NUM> millimeters. The two rows of metal sheet <NUM> may also be obtained by stamping an integral metal piece.

The two rows of metal sheet <NUM> are arranged in parallel and spaced apart from each other, and each of the metal sheets <NUM> in a same row is aligned with each other.

Each metal sheet <NUM> at one row has one end extending to the corresponding metal sheet <NUM> at the other row, and the other ends of the each metal sheet <NUM> connects with each other to form a positioning portion <NUM>. The positioning portion <NUM> is further defined with a plurality of positioning through holes <NUM>.

In some embodiments, the metal strips may be divided into thirty-six or forty or forty-eight metal sheets <NUM> arranged in parallel and spaced apart from each other, the interval between every two adjacent metal sheets <NUM> is equal, and the interval may be <NUM> millimeter to <NUM> millimeters.

Operation S2, a plurality of brackets are provided, and each bracket is located between two corresponding metal sheets and fixedly connected to the two metal sheets.

Specifically, referring to <FIG>, a plurality of brackets <NUM> are prepared, each bracket <NUM> is fixedly connected with two metal sheets <NUM>, and the two metal sheets <NUM> are located in different rows and facing to each other. As such, each two corresponding metal sheets <NUM> are connected by a bracket <NUM>.

In some embodiments, the bracket <NUM> may be obtained by dividing a bracket assembly, which includes a plurality of brackets connected in parallel side by side. The bracket assembly may include thirty-six or forty or forty-eight brackets, and is made of ceramic or glass. Each of the brackets <NUM> may have a same width, such as <NUM> millimeters, <NUM> millimeter, <NUM> millimeters, or <NUM> millimeters. It should be understood that, the width of each of the bracket <NUM> may not be the same, and may be set according to an actual need.

In the invention, referring to <FIG> and <FIG>, in the operation S2, one end of each of the metal sheets <NUM> is defined with a clamping portion <NUM> for clamping the bracket <NUM>. Specifically, the clamping portion <NUM> includes a pair of clamping pieces <NUM> and <NUM>, and the clamping pieces <NUM> and <NUM> face to each other and are spaced apart from each other. The pair of clamping pieces are respectively bent and extended from opposite two sides of the metal sheet, and cooperatively define a receiving cavity <NUM> with the metal sheet <NUM>, so that the end of the bracket <NUM> can be received in the receiving cavity <NUM>. It can be understood that, the clamping portion <NUM> can also be integrally formed with the metal sheet <NUM> in operation S1.

In some embodiments, there is a one-to-one correspondence between the plurality of positioning through holes <NUM> and the brackets <NUM>, so as to facilitate the positioning of the brackets <NUM> when being connected to the metal sheets <NUM>.

In some embodiments, referring to <FIG> and <FIG>, each of the metal sheets <NUM> is further defined with a marking hole <NUM>. The marking hole <NUM> is configured to identify the positive pole and negative pole of the metal sheet <NUM>, for instance, the metal sheet <NUM> having the marking hole <NUM> is set as a positive pole, and the metal sheet <NUM> without the marking hole <NUM> is set as a negative pole, or vice versa. The marking hole <NUM> may facilitate the identification of the positive pole and the negative pole in a subsequent process of solid-state wire bonding. It should be understood that the marking hole <NUM> may also be integrally formed with the metal sheet <NUM> in operation S1.

Operation S3, a plurality of LED chips are provided and attached to each of the brackets, and the LED chips are electrically connected to the metal sheets by conducting wire; or, each bracket is prefabricated with conducting strip, and the LED chips are attached to the bracket and electrically connected to the metal sheets by the conducting strip.

Specifically, referring to <FIG>, in one embodiment, one of the brackets <NUM> is taken as an example. The bracket <NUM> is printed with two conducting strips <NUM> at two sides of the bracket <NUM>. Then, a set number of LED chips <NUM> are sequentially attached to the bracket <NUM> and positioned between the two conducting strips <NUM>. Finally, each of the conducting strips <NUM> is electrically connected to the metal sheets <NUM> located near to its both ends by welding lead, and the LED chips <NUM> are electrically connected to the conducting strips <NUM> via conducting wires.

The LED chips <NUM> may be high-voltage chips or low-voltage chips, which is not limited in the present disclosure.

Each bracket <NUM> is attached with a rectifier module <NUM>, which is positioned at an end of the bracket <NUM> closing to the metal sheet <NUM>.

The rectifier module <NUM> may specifically include a rectifier bridge <NUM> and a protective resistor <NUM>. The rectifier bridge <NUM> may be consisted of four high-voltage LED chips with different conduction directions, so as to be able to convert external AC power to DC power to enable the LED chips <NUM>. The protective resistor <NUM> is configured for stabilizing the current and voltage when the LED filament is forwarded and reversely cut-off, so as to effectively avoid the AC LED filament from breakdown due to overcurrent and overvoltage during work. In other embodiments, the rectifier module <NUM> may include only the rectifier bridge <NUM>, which is not limited in the present disclosure.

It should be understood that, by arranging the rectifier module <NUM> on the bracket <NUM>, the LED filament that is finally manufactured can be directly connected to an AC power, which takes a lower cost than that of the conventional DC filament, and the power supply adopted for the LED filament may also be a lowcost power supply. Further, the stability of the AC LED filament is effectively improved, and the occurrence of die modulation phenomenon which may be caused by the instability of a crude power supply's filtering and voltage reduction is reduced. In addition, the method for manufacturing the AC LED filament does not need many of the components as used in many power supply solutions, such as expensive rectifiers and capacitors, thereby further reducing the cost.

Please referring to <FIG>, according to another embodiment of the present disclosure, a set number of LED chips <NUM>, such as eight or ten LED chips <NUM>, are sequentially arranged and fixed to the bracket <NUM> and electrically connected with each other through a conducting wire <NUM>, and the LED chips <NUM> are then electrically connected to the corresponding metal sheets <NUM> by the conducting wire <NUM>.

Optionally, the quantity of the LED chips <NUM> attached to the bracket <NUM> may be set according to actual requirement. Other logical circuits can also be set by setting reasonable bonding positions and wire bonding methods. It is not limited in the present disclosure.

Operation S4, referring to <FIG>, each bracket, the LED chips defined on the bracket, the conducting strip or the conducting wire defined on the bracket, and the joints of the bracket and the metal sheets are all cladded using packaging material to form an encapsulation layer <NUM>, and the encapsulation layer <NUM>, the bracket <NUM>, the LED chips <NUM>, the conducting strip <NUM> and/ or conducting wires <NUM>, and the connected two metal sheets <NUM> cooperatively form an LED filament.

Specifically, referring to <FIG>, <FIG>, in one embodiment, after the LED chips <NUM> being attached to the bracket <NUM> and electrically connected to the metal sheets <NUM> by conducting strip <NUM> and/or conducting wire <NUM>, packaging material is used to package the bracket <NUM>, the LED chips <NUM> and conducting strip <NUM> (and/or conducting wire <NUM>), and the joints of the bracket <NUM> and the metal sheets <NUM> to form an encapsulation layer <NUM>. The encapsulation layer <NUM>, the bracket <NUM>, the LED chips <NUM>, the conducting strip <NUM> or conducting wire <NUM>, and the connected two metal sheets <NUM> cooperatively form the final LED filament. Specifically, the clamping portion <NUM> is also cladded by the encapsulation layer <NUM>.

The packaging layer <NUM> may completely isolate the LED chips <NUM> and the bracket <NUM> from air, so that oxidation of the LED chips <NUM> and the bracket <NUM> may be avoided, and a good environment is provided for the LED chips <NUM> to run well in a confined space. As such, the using life of the LED filament is also greatly improved. The encapsulation layer <NUM> also wraps the joints of the metal sheets <NUM> and the bracket <NUM>, which may reduce the possibility of the joints from being broken due to external influences, thereby the using life of the LED filament is further improved.

The packaging material used for the packaging layer <NUM> may be one or more selected from a group consisting of silicone, rubber, resin, and fluorescent powder. It is not limited in the present disclosure.

In some embodiment, the method for manufacturing LED filament further includes operation S5 subsequent to the operation S4.

Operation S5, the metal sheet <NUM> is cut off at a position located between the positioning portion <NUM> and the joint of the bracket and the metal sheet to obtain separate LED filaments. The joint relates to the clamping portion <NUM> for clamping the bracket <NUM>.

Specifically, the metal sheet <NUM> is cut off at each of the positions located between the positioning portion <NUM> and the joint of the bracket <NUM> and the metal sheet <NUM>, to obtain a plurality of separate LED filaments.

More specifically, the metal sheet <NUM> is cut off at each of the positions between the marking hole <NUM> and the positioning through hole <NUM>, to obtain a plurality of LED filaments for separately using.

Compared to the related art, the method for manufacturing LED filament in the present disclosure can produce LED filament groups in batches, which simples the process and reduces the cost. Further, the encapsulation layer may completely isolate the LED chips and the brackets from air, so that oxidation of the LED chips and the brackets may be avoided, and a good environment is provided for the LED chips to run well in a confined space. As such, the using life of the LED filament is also greatly improved.

Claim 1:
A method for manufacturing an LED filament, comprising:
operation S1, providing a plurality of metal sheets (<NUM>) arranged in two rows in parallel, each metal sheet (<NUM>) at one row having one end extending to the corresponding metal sheet at the other row, and the other ends of the metal sheets (<NUM>) at said one row connecting with each other to form a positioning portion (<NUM>);
operation S2, providing a plurality of brackets (<NUM>), and each bracket (<NUM>) being located between two corresponding metal sheets (<NUM>) and fixedly connected to the two metal sheets (<NUM>), the two corresponding metal sheets (<NUM>) being located in different rows and facing to each other, each of the metal sheets (<NUM>) defining a clamping part (<NUM>) for clamping the bracket (<NUM>);
operation S3, providing a plurality of LED chips (<NUM>) and attaching the LED chips (<NUM>) to each of the brackets (<NUM>), and the LED chips (<NUM>) being electrically connected to the metal sheets (<NUM>) by conducting wire (<NUM>);
operation S4, packaging each bracket (<NUM>), the LED chips (<NUM>) defined on the bracket (<NUM>), the conducting strip (<NUM>) or the conducting wire (<NUM>) defined on the bracket (<NUM>), and the joint of the bracket (<NUM>) and the metal sheet (<NUM>) using packaging material to form an encapsulation layer (<NUM>);
the encapsulation layer (<NUM>), the bracket (<NUM>), the LED chips (<NUM>), the conducting strip (<NUM>) and/or conducting wire (<NUM>), and the connected two metal sheets (<NUM>) cooperatively forming the LED filament; and
each of the brackets (<NUM>) being attached with a rectifier module (<NUM>), and
the rectifier module (<NUM>) being defined at an end of the bracket (<NUM>) closing to the metal sheet (<NUM>).