JP2011059402A - Image display device using led - Google Patents

Image display device using led Download PDF

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Publication number
JP2011059402A
JP2011059402A JP2009209330A JP2009209330A JP2011059402A JP 2011059402 A JP2011059402 A JP 2011059402A JP 2009209330 A JP2009209330 A JP 2009209330A JP 2009209330 A JP2009209330 A JP 2009209330A JP 2011059402 A JP2011059402 A JP 2011059402A
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Prior art keywords
led
display device
input
voltage
series
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Katsumi Tabuchi
勝美 田渕
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CREATIVE DAIWA CO Ltd
Ryoden Trading Co Ltd
DHS Co Ltd
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CREATIVE DAIWA CO Ltd
Ryoden Trading Co Ltd
DHS Co Ltd
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Priority to JP2009209330A priority Critical patent/JP2011059402A/en
Publication of JP2011059402A publication Critical patent/JP2011059402A/en
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device using light-emitting diodes (LEDs), which endures a serge voltage from an AC input and thermal stress, while assuring stable illuminance. <P>SOLUTION: In the display device using an LED including: a rectifying circuit 2 for rectifying an AC input of a commercial alternate current(AC) voltage, and outputting it; and a plurality of LEDs 3 connected in series with this output used as input, a varistor 5 is connected between lines of AC input, and an overheat protective circuit 6 is connected to the plurality of LEDs 3 in series. Breakdown of the display device is prevented by preventing serge voltage from flowing from the commercial AC power supply by the varistor 5. The display device uses the LEDs with excellent reliability, which can prevent heat from being generated and raised to a prescribed temperature or more, by the overheat protective circuit 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、複数のＬＥＤ（発光ダイオード）を直列に接続した回路に商用交流電圧を整流した電圧を加えてＬＥＤを発光させて看板等に用いることのできるＬＥＤを用いた表示装置に関するものである。   The present invention relates to a display device using an LED that can be used for a signboard or the like by applying a voltage obtained by rectifying a commercial AC voltage to a circuit in which a plurality of LEDs (light emitting diodes) are connected in series to emit light. .

従来、店舗看板やサイン看板用の光源として白熱ランプや蛍光灯が使用されてきたが、環境負荷低減の観点から省電力で長寿命なＬＥＤの使用が急速に拡大してきている。   Conventionally, incandescent lamps and fluorescent lamps have been used as light sources for store signboards and signboards, but the use of power-saving and long-life LEDs has been rapidly expanding from the viewpoint of reducing environmental impact.

この種ＬＥＤを用いた表示装置の従来の技術を図４〜図６により説明する。   A conventional technique of a display device using this kind of LED will be described with reference to FIGS.

図４は従来のＬＥＤを用いた表示装置の回路図であり、図５は同電流波形図であり、図６は他のＬＥＤを用いた表示装置の回路図である。   4 is a circuit diagram of a display device using a conventional LED, FIG. 5 is a waveform diagram of the current, and FIG. 6 is a circuit diagram of a display device using another LED.

同図によると、１は過電流保護用のヒューズであり、２は整流回路であり、一般的には複数のダイオードによって全波整流が行われる。   According to the figure, 1 is a fuse for overcurrent protection, 2 is a rectifier circuit, and full-wave rectification is generally performed by a plurality of diodes.

３はＬＥＤであり、複数個（図４においては４個）が直列に接続されて必要とされる発光照度を確保するとともに、複数個が直列に接続された固定抵抗４に接続されている。   Reference numeral 3 denotes an LED, and a plurality (four in FIG. 4) are connected in series to ensure the required light emission illuminance, and the plurality are connected to a fixed resistor 4 connected in series.

なお、前記固定抵抗４はＬＥＤに流れる電流を制限するためのものであるが、複数個直列接続する構成とする事で、この固定抵抗４の通電によって発生する損失熱を分散させている。なお、図５は前記ＬＥＤ３に流れる電流波形図である。   The fixed resistor 4 is for limiting the current flowing through the LED, but the heat loss generated by energization of the fixed resistor 4 is dispersed by connecting a plurality of the fixed resistors 4 in series. FIG. 5 is a waveform diagram of a current flowing through the LED 3.

以上のように構成されたＬＥＤを用いた表示装置は、商用交流電源からの入力を整流回路２で脈流となった直流に変換し、これをＬＥＤ３に入力してこれらＬＥＤ３を発光表示させるものである。   The display device using the LEDs configured as described above converts an input from a commercial AC power source into a direct current that becomes a pulsating current in the rectifier circuit 2 and inputs this to the LED 3 to cause the LED 3 to emit light. It is.

なお、このＬＥＤを用いた表示装置を看板等に使用する場合は、文字や図形の形にこの表示装置を単体ユニットとして多数個並べ、商用交流電源に並列にこの表示装置を接続して文字や図形の形に表示させて使用することになる。   When a display device using this LED is used for a signboard or the like, a large number of this display device is arranged as a single unit in the form of characters or figures, and this display device is connected in parallel with a commercial AC power It will be used in the form of a graphic.

図６は、他の従来のＬＥＤを用いた発光装置の回路図であり、図４の従来技術との相違点のみ説明すると、整流回路２からの出力端に接続された平滑用コンデンサ７を接続するとともに、ＬＥＤ３に直列に定電流ダイオード８を接続した点である。   FIG. 6 is a circuit diagram of a light emitting device using another conventional LED, and only the difference from the prior art of FIG. 4 will be described. A smoothing capacitor 7 connected to the output terminal from the rectifier circuit 2 is connected. In addition, the constant current diode 8 is connected to the LED 3 in series.

以上の構成により、平滑用コンデンサ７によって整流回路２からの直流に整流された直流電圧の変動を小さくして、ＡＣ入力電圧の変化によるＬＥＤ３に流れる電流の変動を小さくするとともに、定電流ダイオード８によってＬＥＤ３に流れる直流電流の安定化を図り、安定した照度の確保を可能とするものである。   With the above configuration, the fluctuation of the DC voltage rectified to the direct current from the rectifier circuit 2 by the smoothing capacitor 7 is reduced, the fluctuation of the current flowing through the LED 3 due to the change of the AC input voltage is reduced, and the constant current diode 8 Thus, the direct current flowing through the LED 3 is stabilized, and stable illuminance can be secured.

このような従来のＬＥＤを用いた表示装置には特許文献１に記載のものがある。   There exists a thing of patent document 1 in the display apparatus using such conventional LED.

特開２００９−１６４９３号公報JP 2009-16493 A

しかしながら、従来技術によるＬＥＤを用いた表示装置では、看板用等として必要な信頼性と長寿命で安定した照度を確保することが十分に発揮されないといった問題があった。   However, the display device using LEDs according to the prior art has a problem in that it cannot sufficiently exhibit the reliability necessary for a signboard or the like and a long life and stable illuminance.

即ち、看板は外部環境からのストレスに曝される可能性が高く、ＡＣ入力ラインからのサージ電圧に対する保護、直射日光などからの熱および自己通電による発熱に対する信頼性の十分な確保が実用上必須となっていた。   In other words, the signboard is likely to be exposed to stress from the outside environment, and it is practically essential to protect against surge voltage from the AC input line, and to ensure sufficient reliability against heat from direct sunlight and heat generated by self-energization. It was.

上記課題を解決するために本発明は、複数のＬＥＤを直列に接続した回路に商用交流電圧を整流した電圧を加えてＬＥＤを発光させるＬＥＤを用いた表示装置において、ＡＣ入力ライン間にバリスタ（電圧依存性抵抗素子）を接続するとともに、前記ＬＥＤと直列に過熱保護回路を接続してＬＥＤを用いた表示装置を構成したものである。   In order to solve the above-described problems, the present invention provides a display device using an LED that emits light by adding a voltage obtained by rectifying a commercial AC voltage to a circuit in which a plurality of LEDs are connected in series. A voltage-dependent resistance element) is connected, and an overheat protection circuit is connected in series with the LED to constitute a display device using the LED.

本発明によれば、ＡＣ入力ライン間に接続したバリスタによって商用交流電圧に紛れ込んだ落雷による急激な異常電圧等のＡＣ入力サージを吸収でき、ＬＥＤに過大な電圧が印加されることを防止し、またＬＥＤと直列に接続した過熱保護回路の動作によって装置自体の温度が高くなっても、ＬＥＤの電流を抑制してＬＥＤの過熱による劣化を防止し、信頼性に優れたＬＥＤを用いた表示装置の提供を可能とするものである。   According to the present invention, it is possible to absorb an AC input surge such as a sudden abnormal voltage caused by a lightning strike mixed in a commercial AC voltage by a varistor connected between AC input lines, preventing an excessive voltage from being applied to the LED, In addition, even when the temperature of the device itself increases due to the operation of the overheat protection circuit connected in series with the LED, the LED current is suppressed to prevent deterioration due to overheating of the LED, and the display device using the LED having excellent reliability Can be provided.

本発明の一実施の形態のＬＥＤを用いた表示装置の回路構成図(実施例１)。The circuit block diagram of the display apparatus using LED of one embodiment of this invention (Example 1). 同他の実施の形態の回路構成図(実施例２)。The circuit block diagram of other embodiment (Example 2). 同回路構成図の要部である定電流回路の回路図(実施例２)。The circuit diagram of the constant current circuit which is the principal part of the circuit block diagram (Example 2). 従来技術のＬＥＤを用いた表示装置の回路構成図。The circuit block diagram of the display apparatus using LED of a prior art. 同ＬＥＤに流れる電流波形図。The current waveform figure which flows into the LED. 同他の従来技術のＬＥＤを用いた表示装置の回路構成図。The circuit block diagram of the display apparatus using LED of another prior art same as the above.

以下本発明の一実施の形態のＬＥＤを用いた表示装置について、図１（実施例１）、図２（実施例２）および図３（実施例２）により説明する。   Hereinafter, a display device using an LED according to an embodiment of the present invention will be described with reference to FIG. 1 (Example 1), FIG. 2 (Example 2), and FIG. 3 (Example 2).

なお、説明にあたっては、従来技術と同一部分は同一番号を付して説明を省略して説明する。   In the description, the same parts as those in the prior art will be denoted by the same reference numerals and the description thereof will be omitted.

（実施例１）
図１は本発明のＬＥＤを用いた表示装置の一実施例の回路図である。同図により従来技術との相違点のみ説明すると、５は商用電源入力(ＡＣ入力ライン)間に接続されたサージ電圧吸収用のバリスタ(電圧・電流特性が非線形である電圧依存性抵抗素子でサージアブソーバとも言われている)であり、６は前記ＬＥＤに直列に接続された過熱保護回路であり、正の温度特性を有する抵抗素子で構成され、抵抗素子の温度がある温度以上になると急激に抵抗値が大きくなるもので、セラミックやポリマーからなり、ポジスタやポリスイッチとも呼ばれているものである。 Example 1
FIG. 1 is a circuit diagram of an embodiment of a display device using the LED of the present invention. Only the differences from the prior art will be explained with reference to the figure. Reference numeral 5 denotes a surge voltage absorbing varistor connected between commercial power supply inputs (AC input lines) (a voltage-dependent resistance element with non-linear voltage / current characteristics). 6 is an overheat protection circuit connected in series with the LED, and is composed of a resistance element having a positive temperature characteristic. When the temperature of the resistance element rises above a certain temperature, it suddenly increases. It has a large resistance value, is made of ceramic or polymer, and is also called a posistor or polyswitch.

なお、前記過熱保護回路６の抵抗値は前記固定抵抗４の抵抗値（合成抵抗）より通常状態では極めて小さく設定されており、ＬＥＤ３の電流値は前記固定抵抗４の抵抗値（合成抵抗）によって決定されている。   The resistance value of the overheat protection circuit 6 is set to be extremely smaller than the resistance value (combined resistance) of the fixed resistor 4 in a normal state, and the current value of the LED 3 depends on the resistance value (combined resistance) of the fixed resistor 4. It has been decided.

以上のようにＬＥＤの表示装置を構成したので、落雷などの影響でＡＣ入力に瞬間的に過大な電圧が入力したときはバリスタ５によって過大入力をパス（吸収）して表示装置の破壊を回避するとともに、表示装置の温度がある温度以上に達した場合は、過熱保護回路６の抵抗値が固定抵抗４の値に比較して極めて大きくなり、ＬＥＤ３の電流を下げ、ＬＥＤ３の過度な温度上昇を防止してＬＥＤ３の劣化を防止するものである。   Since the LED display device is configured as described above, when an excessive voltage is instantaneously input to the AC input due to lightning strikes, the varistor 5 passes (absorbs) the excessive input to avoid destruction of the display device. In addition, when the temperature of the display device reaches a certain temperature or more, the resistance value of the overheat protection circuit 6 becomes extremely larger than the value of the fixed resistor 4, the current of the LED 3 is lowered, and the temperature of the LED 3 is excessively increased. This prevents the deterioration of the LED 3.

（実施例２）
次に、他の実施例のＬＥＤの表示装置を図２および図３により説明する。図２は他の実施例の回路図であり、図３は同要部である定電流回路の回路図である。 (Example 2)
Next, an LED display device according to another embodiment will be described with reference to FIGS. FIG. 2 is a circuit diagram of another embodiment, and FIG. 3 is a circuit diagram of a constant current circuit as the main part.

同図により、図１の実施例１の回路図との相違点を説明すると、実施例１において用いたＬＥＤ３に直列接続された固定抵抗４に代えて定電流回路９をＬＥＤ３に直列に接続したものである。   The difference from the circuit diagram of the first embodiment shown in FIG. 1 will be described with reference to FIG. 1. A constant current circuit 9 is connected in series to the LED 3 instead of the fixed resistor 4 connected in series to the LED 3 used in the first embodiment. Is.

定電流回路９は、ｎｐｎのトランジスタ１０のエミッタに固定抵抗１３の一端を接続し、ベースと固定抵抗１３の他方の端子間に定電圧ダイオード１１を接続、コレクタとベース間に固定抵抗１２を接続して構成される定電流回路である。   In the constant current circuit 9, one end of a fixed resistor 13 is connected to the emitter of an npn transistor 10, a constant voltage diode 11 is connected between the other terminal of the base and the fixed resistor 13, and a fixed resistor 12 is connected between the collector and the base. This is a constant current circuit configured as described above.

この定電流回路９の定電流値は、ほぼ定電圧ダイオード１１と固定抵抗１３で決定される。従来技術の図６で説明した定電流ダイオード８を使用したものに比較し、定電流値がＬＥＤ３の特性に併せて自由に設定が可能となる。   The constant current value of the constant current circuit 9 is almost determined by the constant voltage diode 11 and the fixed resistor 13. The constant current value can be freely set in accordance with the characteristics of the LED 3 as compared with the prior art using the constant current diode 8 described with reference to FIG.

更に、前記定電流回路９の耐電圧がｎｐｎのトランジスタ１０の耐電圧で確保可能なことから、ＡＣ入力ラインからのサージ電圧は前記バリスタ５で抑制されるが、抑制しても商用交流電圧に比べるとはるかに大きなピーク電圧が表示装置に印加されることになるため、その耐電圧をこの定電流回路９で確保することが可能となるものである。   Furthermore, since the withstand voltage of the constant current circuit 9 can be secured by the withstand voltage of the npn transistor 10, the surge voltage from the AC input line is suppressed by the varistor 5, but even if it is suppressed, it becomes a commercial AC voltage. In comparison, since a much larger peak voltage is applied to the display device, the withstand voltage can be secured by the constant current circuit 9.

以上のように本発明は、外部からの衝撃的な異常入力によるＬＥＤの破壊を防止するとともに、急激な温度上昇も抑制するものであり、看板等の表示用に限らず、ＬＥＤを用いた表示や照明装置の信頼性の向上にも寄与できるものである。   As described above, the present invention prevents destruction of the LED due to shocking abnormal input from the outside and suppresses a rapid temperature rise, and is not limited to display of a signboard or the like. It can also contribute to improving the reliability of lighting devices.

１ 過電流ヒューズ
２ 整流用ダイオード
３ ＬＥＤ
４，１２，１３ 固定抵抗
５ バリスタ
６ 過熱保護回路
７ コンデンサ
８ 定電流ダイオード
９ 定電流回路
１０ トランジスタ
１１ 定電圧ダイオード 1 Overcurrent fuse 2 Rectifier diode 3 LED
4, 12, 13 Fixed resistance 5 Varistor 6 Overheat protection circuit 7 Capacitor 8 Constant current diode 9 Constant current circuit 10 Transistor 11 Constant voltage diode

Claims (3)

商用交流電源からのＡＣ入力を整流して出力する整流回路とこの出力を入力とする直列接続された複数のＬＥＤからなるＬＥＤを用いた表示装置において、ＡＣ入力ライン間にバリスタを接続するとともに、前記ＬＥＤと直列に過熱保護回路を接続したことを特徴とするＬＥＤを用いた表示装置。   In a display device using a rectifier circuit that rectifies and outputs an AC input from a commercial AC power supply and a plurality of LEDs connected in series with the output as an input, a varistor is connected between the AC input lines, A display device using an LED, wherein an overheat protection circuit is connected in series with the LED. 前記過熱保護回路は、セラミックやポリマーからなる正の温度特性素子で構成されることを特徴とする請求項１記載のＬＥＤを用いた表示装置。   2. The display device using an LED according to claim 1, wherein the overheat protection circuit includes a positive temperature characteristic element made of ceramic or polymer. 直列接続された前記複数のＬＥＤと前記過熱保護回路に、更に、直列に定電流回路を接続した請求項１または請求項２に記載のＬＥＤを用いた表示装置。   The display device using the LED according to claim 1, further comprising a constant current circuit connected in series to the plurality of LEDs connected in series and the overheat protection circuit.
JP2009209330A 2009-09-10 2009-09-10 Image display device using led Pending JP2011059402A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103499121A (en) * 2013-09-02 2014-01-08 遵义航阳电器厂 Triple protection measures of foot warming box
JP2014096576A (en) * 2012-10-10 2014-05-22 Citizen Electronics Co Ltd LED Drive circuit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014096576A (en) * 2012-10-10 2014-05-22 Citizen Electronics Co Ltd LED Drive circuit
CN103499121A (en) * 2013-09-02 2014-01-08 遵义航阳电器厂 Triple protection measures of foot warming box

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