JPH09154287A - Piezoelectric transformer/inverter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize short arrangement of the lead wire by individually arranging the high voltage output terminal and low voltage output terminal of a piezoelectric transformer/inverter formed on a rectangular circuit board in both sides thereof, providing in parallel an input side connector to a low voltage side output terminal and individually providing a high voltage side output terminal. SOLUTION: In an inverter 1 for a liquid crystal back light, a low voltage side input connector 2 and a high voltage side connector 3 are arranged in both sides of a narrow and longer printed circuit board 6. The low voltage side input connector 2 is provided an input side terminal 10 and an output side low voltage terminal 3b to connect an electronic circuit 8 and a piezoelectric transformer 9 via a pattern 7. An output of the inverter 1 is output from the output side connector 3 independent of the high voltage side terminal 3a. By way of a lead wire 5, the high voltage side terminal 3a and low voltage side terminal 3b are connected to a cathode ray tube 4. Thereby, the lead wire is shortened and fluctuation of stray capacitance can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter in which a creepage distance between a high voltage side terminal and a low voltage side terminal is extended.

[0002]

2. Description of the Related Art A conventional inverter 100 includes an input connector 20 and an electronic circuit 8 on a substrate 15 as shown in FIG.
0, an electromagnetic transformer 90, an output connector 30, a pattern 70 connecting them, and the like. The output terminal uses the 2-pin connector 30 of the pins 30a and 30b, the high voltage output side pin 30a is connected to one of the backlights 40, and the other pin 30b is connected to the low voltage feedback terminal. In order to secure the creepage distance 65 between both terminals of the connector 30, a method of separating the distance between the pins 30a and 30b, inserting a slit 60 between both terminals, or inserting a slit 61 between patterns has been adopted. However, downsizing of parts
Due to the demand for lighter weight and higher performance, it has become impossible to increase the distance between the terminals of the connector, and the slits have a problem that the strength of the connector and the board is impaired. The output of the inverter is required to have a high voltage for higher performance, and the necessity of extending the creepage distance 65 is increasing more and more. In addition, the screen is becoming larger, and when the lead 50 is pulled out from the 2-pin connector 30, the lead length for routing becomes long and the stray capacitance increases, or the stray capacitance changes depending on the position of the lead. Then, there was a big problem as an inverter for a liquid crystal backlight.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and secures a creepage distance between output terminals of an inverter to improve the withstand voltage and leads from the inverter to a liquid crystal backlight. The object is to reduce the stray capacitance due to the leads by shortening the length and reduce the stray capacitance due to the leads.

[0004]

In order to achieve the above object, the present invention is a piezoelectric transformer inverter having a circuit formed on a rectangular substrate, wherein a high voltage side output terminal and a low voltage side output terminal are provided on the substrate. Provided is a piezoelectric transformer inverter which is arranged separately at both ends. Further, there is provided a piezoelectric transformer inverter in which the low-voltage side terminal is provided side by side with an input-side connector and the high-voltage side output terminal is independently arranged. Also provided is a piezoelectric transformer inverter in which the piezoelectric transformer inverter is formed into a circuit on a rectangular substrate having a width of 10 mm or less. Also, a liquid crystal backlight module is provided in which a piezoelectric transformer inverter is arranged along both sides of an LCD backlight having side edges having input terminals, and the piezoelectric transformer inverter and the terminals on the same side of the liquid crystal backlight are connected to each other. To do.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of the inverter of the present invention. The liquid crystal backlight inverter 1 has a narrow width, and a connector 2 having input terminals 10 and output low-voltage terminals 3b on both ends of an elongated printed board 6 and a connector 3 having only output high-voltage terminals 3a. Is arranged, the electronic circuit 8
And a piezoelectric transformer 9 and a pattern 7 connecting them. The output of the inverter 1 is output from the output side connector 3 in which the high voltage side terminal 3a is independent, and the low voltage side terminal 3b is input from the terminal 36 attached to the input side connector 2 and the liquid crystal back via the lead 5. They are connected to the terminals of the light 4, respectively. Even if the output terminals are separate, since the low-voltage side terminal 3b is provided side by side with the input side connector 2, the number of connectors is the same as the conventional one and the number of working steps does not increase. Since the output terminal is divided into the high voltage side terminal 3a and the low voltage side terminal 3b and the high voltage side terminal 3a is independent, it is possible to secure a sufficient creepage distance between the terminals even on a narrow and narrow printed circuit board and improve the dielectric strength voltage. Can be made. Further, unlike the conventional case, it is not necessary to form slits for extending the creepage distance in the connector or the printed circuit board, so that the strength is not impaired.

FIG. 2 is a conceptual diagram showing the positional relationship between the liquid crystal panel 11 and the inverter 1. A CCFL (cold-cathode tube) 4 is attached to one side or both sides of the liquid crystal panel 11 so that the side length of the liquid crystal panel 11 is full. Thus, the entire surface of the liquid crystal panel 11 can be illuminated. The printed circuit board 6 of the inverter 1 is designed to have a length substantially equal to the length of the CCFL (cold-cathode tube) 4, and the high-voltage side connector 3 and the low-voltage side connector 2 are arranged at both ends of the board 6 so that the terminals can be separated from the terminals. The length of the lead 5 drawn out can be shortened, and even if the liquid crystal panel 11 becomes large, the stray capacitance due to the lead 5 does not change, and the variation in stray capacitance due to the leading of the lead 5 can be realized. It was possible to obtain an excellent liquid crystal backlight module that does not cause the problem of interference with the liquid crystal panel 11 due to fluctuations in the output frequency. The above description has been made on the assumption that the light source used for the liquid crystal backlight is a fluorescent lamp or the like, but an EL backlight can also be used.

[0007]

The width of the printed circuit board 6 of the liquid crystal backlight inverter 1 of the embodiment is limited to 10 mm from the relationship between the width of the liquid crystal panel 10 and the width of electronic equipment.
Since a high voltage of 1700V is output, it is 8 between both terminals.
A creepage distance of mm or more is required. However, it is impossible to mount a 2-pin connector having a pin interval of 8 mm on the printed circuit board 6 having a width of 10 mm, and the output cannot be obtained from the same connector. Therefore, the high-voltage side terminal 3a is independently connected to the high-voltage side connector 3, arranged on one end side of the printed circuit board 6, and the other end side is provided side by side with the input-side connector 2 to connect the low-voltage side output terminal 3b to the input-side connector 2. Connected to and placed.

In addition, since the transformer used in this inverter is a conventional electromagnetic transformer, if the width is set to 10 mm, the efficiency is lowered. Therefore, the piezoelectric transformer 9 is used.
The pattern of the inverter circuit was printed on the front and back of the printed circuit board 6, and the pattern was arranged near the center of the board to secure the creeping distance between the front and back patterns. Further, in order to secure the creepage distance between the high voltage side and the low voltage side on the circuit, the pattern is divided, an insulating substrate is inserted between them, and a four-layer printed circuit board is also used. In this case, since the pattern is embedded in the insulating substrate, the concept of creepage distance is unnecessary. In the case of this embodiment, 9.4
LCD backlight 4 is used though inch TFT panel is used.
Since the inverter 1 is aligned with the inverter 1 and the leads 5 are connected from both ends thereof and connected, a lead wire of the lead 5 is short, and therefore variations are small and a stray capacitance is small, and a piezoelectric transformer inverter module is completed.

[0009]

The creepage distance between the high-voltage side terminal and the low-voltage side terminal of the inverter can be easily secured, and the withstand voltage can be improved. In addition, the length of the lead from the inverter to the LCD backlight was shortened to reduce the stray capacitance due to the lead, and it was possible to reduce the lead distribution and suppress variations in the stray capacitance. A piezoelectric transformer inverter module was completed.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an inverter of the present invention.

FIG. 2 is a conceptual diagram of an inverter module of the present invention.

FIG. 3 is a conceptual diagram of a conventional inverter

[Explanation of symbols]

 1 Inverter 2 Input side connector with low voltage side connector 3 High voltage side output connector 4 CCFL (cold cathode tube)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H05B 41/02 H05K 1/18 B 41/24 H02M 3/24 H H05K 1/02 H01L 27/04 E 1/18 41/08 A // H02M 3/24

Claims (4)

[Claims] 1. A piezoelectric transformer inverter having a circuit formed on a rectangular substrate, wherein a high-voltage side output terminal and a low-voltage side output terminal are separately arranged at both ends of the substrate. Inverter. 2. The piezoelectric transformer inverter according to claim 1, wherein the low-voltage side output terminal is provided side by side with an input-side connector, and the high-voltage side terminal is arranged independently. 3. The thick electric transformer inverter according to claim 1, wherein the rectangular substrate has a width of 10 mm or less. 4. The piezoelectric transformer inverter according to claim 1 or 2 is disposed alongside a side having input terminals at both ends of a liquid crystal backlight, and the piezoelectric transformer inverter and the terminal on the same side of the liquid crystal backlight. LCD backlight module that connects each other.