JP2008064477A - Led destruction detection apparatus - Google Patents
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Abstract
Description
本発明は、ＬＥＤ破壊検出装置に関し、就中、画像処理用照明器具あるいは機器検査用照明器具に組み込むのに有用なＬＥＤ破壊検出装置に関する。 The present invention relates to an LED breakage detection apparatus, and more particularly to an LED breakage detection apparatus useful for incorporation in an image processing lighting apparatus or an apparatus inspection lighting apparatus.
従来、ＬＥＤ照明器具のオープン（断線）破壊検出装置がＬＥＤ信号灯の場合について知られている（例えば、特許文献１参照。）。この装置では、同文献1の図３に示されるように、直列接続されたＬＥＤ素子群を一直列単位とし、この直列単位の複数組が駆動電源に並列接続されている。その際、各直列単位には、さらにフォトカプラを検知素子として直列接続することにより、直列単位毎のオープン破壊を検知可能としている。つまり、この装置は、ＬＥＤの駆動電圧が一定のときに限り、ＬＥＤ素子群のオープン破壊に対応できるように設定されている。 2. Description of the Related Art Conventionally, it has been known that an LED lighting fixture is an LED signal lamp (see, for example, Patent Document 1). In this apparatus, as shown in FIG. 3 of the document 1, a group of LED elements connected in series is used as one series unit, and a plurality of sets of the series units are connected in parallel to a drive power source. At that time, each series unit is further connected in series with a photocoupler as a detection element, so that an open breakdown for each series unit can be detected. That is, this device is set so as to cope with open destruction of the LED element group only when the LED drive voltage is constant.
一方、画像処理用照明器具あるいは機器検査用照明器具では、検査物の色、サイズ、および反射率などに応じて、ＬＥＤの駆動電圧を変化させて所望の照射光量を得ることが多い。しかし、従来の検出装置では、ＬＥＤの駆動電圧が大きく変化した際に、ＬＥＤ破壊を確実に検知することは困難である。しかも、ＬＥＤ破壊モードには、オープン破壊に加えてショート（短絡）破壊も高い確率で含まれるので、ショート破壊の検知も重要になる。ちなみに、上記文献１では、オープン破壊の検知に終始し、ショート破壊の検知についての解決策は何等開示されていない。 On the other hand, in the image processing lighting apparatus or the apparatus inspection lighting apparatus, a desired amount of irradiation light is often obtained by changing the driving voltage of the LED in accordance with the color, size, reflectance, and the like of the inspection object. However, with the conventional detection device, it is difficult to reliably detect the LED breakdown when the LED drive voltage changes greatly. In addition, since the LED destruction mode includes not only open destruction but also short-circuit (short-circuit) destruction with a high probability, detection of short-circuit destruction is also important. Incidentally, in the above-mentioned document 1, since the detection of the open breakage is always performed, no solution for the detection of the short breakage is disclosed.
したがって、本発明の課題は、調光によりＬＥＤの駆動電圧が変化した際にも、ＬＥＤ破壊を正確に検知できるＬＥＤ破壊検出装置を提供することにある。さらに、本発明の他の課題は、ＬＥＤのオープン破壊検知機能に加えて、ＬＥＤのショート破壊をも検知できるＬＥＤ破壊検出装置を提供することにある。 Therefore, the subject of this invention is providing the LED destruction detection apparatus which can detect LED destruction correctly, even when the drive voltage of LED changes by light control. Furthermore, another object of the present invention is to provide an LED break detection device that can detect not only LED open break detection but also LED short break.
本発明者等は、直列接続されたＬＥＤ素子群を一直列単位とし、この直列単位の複数組を駆動電源に並列接続した際に、各直列単位中の一部のＬＥＤ素子を導通検知用素子として兼用させることに注目した。そして、該検知素子から出力されるアノード側電位を、該直列単位に印加される最大駆動電圧および最小駆動電圧（いずれも固定電圧）に対応する２つの固定基準電圧と比較することにより、従来の問題を解消するに至った。また、本発明のさらに好ましい態様によれば、該最大駆動電圧および最小駆動電圧を維持しながら、これら２つの基準電圧に対応する最大側可変駆動電圧および最小側可変駆動電圧を併用することにより、全てのＬＥＤ破壊が破壊モード毎に特定される。 The present inventors set a group of LED elements connected in series as one series unit, and when a plurality of sets of the series units are connected in parallel to a drive power source, some of the LED elements in each series unit are elements for detecting continuity. We paid attention to let it be used as both. Then, by comparing the anode-side potential output from the sensing element with two fixed reference voltages corresponding to the maximum drive voltage and the minimum drive voltage (both fixed voltages) applied in the series unit, The problem was solved. Further, according to a further preferred aspect of the present invention, the maximum variable drive voltage and the minimum variable drive voltage corresponding to these two reference voltages are used in combination while maintaining the maximum drive voltage and the minimum drive voltage. All LED breakdowns are identified for each breakdown mode.
本発明のＬＥＤ破壊検出装置にあっては、以下のような顕著な効果が奏される。
（１）調光時にＬＥＤの駆動電圧を変化させた場合でも、ＬＥＤ破壊を正確に検知できる。
（２）各直列単位中の一部のＬＥＤ素子を検知素子として兼用しているので、追加的検出素子を必要とせず、装置が簡略化される。
（３）該２つの基準電圧に加えて、さらに対応する２つの可変基準電圧を併用することにより、ショート破壊およびオープン破壊が区別されて検知される。
（４）上記（３）において、破壊モード毎の破壊表示素子ないし破壊警告ブザーを併用することにより、ＬＥＤ破壊が瞬時にしかも破壊モードまでが判別できるので、修複等の対処が迅速になる。
In the LED breakage detection device of the present invention, the following remarkable effects are exhibited.
(1) Even when the LED drive voltage is changed during dimming, LED destruction can be detected accurately.
(2) Since some of the LED elements in each series unit are also used as detection elements, an additional detection element is not required and the apparatus is simplified.
(3) In addition to the two reference voltages, two corresponding variable reference voltages are used in combination, so that the short breakdown and the open breakdown are distinguished and detected.
(4) In (3) above, by using a destructive display element or a destructive warning buzzer for each destructive mode, it is possible to determine whether the LED is destructed instantaneously and up to the destructive mode, so that measures such as repairs can be taken quickly.
以下、本発明のＬＥＤ破壊検出装置の一例について、添付図面を参照しながら述べる。
図１は、本発明のＬＥＤ破壊検出装置の一例を示すブロック図である。
図２は、図１のＬＥＤ破壊検出装置の回路図である。
図３は、図１〜図２の装置において、モニタ信号と基準電圧の関係を示すグラフである。
図４は、本発明の別の態様において、モニタ信号と基準電圧の関係を示すグラフである。
図５は、本発明のさらに別の態様において、モニタ信号と基準電圧の関係を示すグラフである。
図６は、上記のさらに別の態様における回路図である。
図７は、本発明のＬＥＤ破壊検出装置を組込んだ検査用のライン状ＬＥＤ照明装置用の斜視図である。
Hereinafter, an example of the LED breakage detection apparatus of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a block diagram showing an example of an LED breakage detection apparatus according to the present invention.
FIG. 2 is a circuit diagram of the LED breakage detection apparatus of FIG.
FIG. 3 is a graph showing the relationship between the monitor signal and the reference voltage in the apparatus of FIGS.
FIG. 4 is a graph showing the relationship between the monitor signal and the reference voltage in another aspect of the present invention.
FIG. 5 is a graph showing the relationship between the monitor signal and the reference voltage in still another aspect of the present invention.
FIG. 6 is a circuit diagram in still another embodiment described above.
FIG. 7 is a perspective view for an inspection line-shaped LED illumination device incorporating the LED breakage detection device of the present invention.
図１〜図２には、本発明の第一の態様が示されている。これらの図において、（１）はＬＥＤ破壊検出部で、検知素子（２）と比較回路（３）と基準電圧回路（４）と破壊判定回路（５）と駆動回路（６）と破壊表示・警告音処理回路（７）とを含む検知回路、ならびに破壊表示素子（８）および／または破壊警告ブザー（９）から構成されている。また、図１のＬＥＤ素子直並列回路では、直列接続されたＬＥＤ素子群を一直列単位とし、この直列単位の複数組が駆動電源に並列接続されている。そして、各直列単位の導通検知素子（２）としては、その直列単位の終端（最下段）のＬＥＤ素子が兼用されている。 1 to 2 show a first embodiment of the present invention. In these drawings, (1) is an LED breakdown detection unit, which includes a detection element (2), a comparison circuit (3), a reference voltage circuit (4), a breakdown determination circuit (5), a drive circuit (6), and a breakdown display. It comprises a detection circuit including a warning sound processing circuit (7), a destruction display element (8) and / or a destruction warning buzzer (9). Further, in the LED element series-parallel circuit of FIG. 1, a group of LED elements connected in series is set as one series unit, and a plurality of sets of the series units are connected in parallel to the drive power supply. And as a conduction | electrical_connection detection element (2) of each series unit, the LED element of the termination | terminus (bottom stage) of the series unit is combined.
図１のＬＥＤ素子直並列回路、さらには導通検知素子（２）、比較回路（３）、および基準電圧回路（４）の詳細は、図２に示されている。 Details of the LED element series-parallel circuit of FIG. 1, and further the continuity detecting element (2), the comparison circuit (3), and the reference voltage circuit (4) are shown in FIG.
図２において、（Ｃ１）〜（Ｃ１２）は各直列単位、（Ｄ１−１〜Ｄ１−９）〜（Ｄ１２−１〜Ｄ１２−９）は、各直列単位（Ｃ１）〜（Ｃ１２）で直列接続されたＬＥＤ素子群で、その際、各直列単位の終端の（Ｄ１−９）〜（Ｄ１２−９）がそれぞれに導通検知素子（２）として機能する。したがって、ここでは、各直列単位（一列）に９個のＬＥＤ素子が直列接続され、さらに、この直列単位が１２個並列配置されている。なお、各直列単位（Ｃ１）〜（Ｃ１２）のＬＥＤ素子群には、図示するように、電流制限抵抗（Ｒ１）〜（Ｒ１２）が直列接続されている。これらは、ＬＥＤ駆動電圧との兼ね合いで、通常数十Ω〜数百Ωに設定される。 In FIG. 2, (C1) to (C12) are serial units, and (D1-1 to D1-9) to (D12-1 to D12-9) are serially connected in series units (C1) to (C12). In this case, the terminal units (D1-9) to (D12-9) of each series unit function as the conduction detecting elements (2), respectively. Therefore, here, nine LED elements are connected in series to each series unit (one row), and 12 series units are arranged in parallel. In addition, as shown in the drawing, current limiting resistors (R1) to (R12) are connected in series to the LED element groups of the series units (C1) to (C12). These are usually set to several tens of ohms to several hundreds of ohms in consideration of the LED driving voltage.
さらに、（Ｖ１）〜（Ｖ１２）は各直列単位（Ｃ１）〜（Ｃ１２）において、導通検知素子（２）のアノード（陽極）側電位を示すモニタ信号、（０１）〜（０１２）は比較回路（３）からの出力信号、（ＶＲ１）および（ＶＲ２）はそれぞれに、比較回路（３）内にてモニタ信号（Ｖ１）〜（Ｖ１２）との比較を行なう最大基準電圧および最小基準電圧、そして、（ＶＬ）は各直列単位（Ｃ１）〜（Ｃ１２）に印加される駆動電圧である。 Further, (V1) to (V12) are monitor signals indicating the anode (anode) side potential of the conduction detecting element (2) in each of the serial units (C1) to (C12), and (01) to (012) are comparison circuits. The output signals (VR1) and (VR2) from (3) are respectively the maximum reference voltage and the minimum reference voltage for comparison with the monitor signals (V1) to (V12) in the comparison circuit (3), and , (VL) are drive voltages applied to the respective series units (C1) to (C12).
各直列単位の最下段に位置するＬＥＤ（Ｄ１−９）〜（Ｄ１２−９）をそれぞれに導通検知素子（２）として兼用するには、例えば、それらのアノード電位（Ｖ１）〜（Ｖ１２）をモニタ信号として常時出力させればよい。このモニタ信号が入力される検知回路には、調光時に各直列単位（Ｃ１）〜（Ｃ１２）への印加電圧が変化したときでも、ＬＥＤ破壊検出に対応できる機能が付与されている。具体的には、調光度合いに応じて各直列単位（Ｃ１）〜（Ｃ１２）に印加される駆動電圧（ＶＬ）の最大駆動電圧（ＶＬmax）および最小駆動電圧（ＶＬmin）に対応して、基準電圧回路（４）内に２つの基準電圧、すなわち最大基準電圧（ＶＲ１）および最小基準電圧（ＶＲ２）を設けている。このような最大基準電圧（ＶＲ１）および最小基準電圧（ＶＲ２）は、電源電圧（ＶＣＣ）を、グランド（Ｇ）に接続された高精度の抵抗（Ｒａ〜Ｒｄ）にて抵抗分圧して固定電圧にすればよい。 In order to use the LEDs (D1-9) to (D12-9) positioned at the bottom of each series unit as the continuity detecting element (2), for example, their anode potentials (V1) to (V12) are used. What is necessary is just to always output as a monitor signal. The detection circuit to which this monitor signal is input is provided with a function that can cope with LED breakage detection even when the applied voltage to each of the series units (C1) to (C12) changes during dimming. Specifically, in accordance with the maximum drive voltage (VLmax) and the minimum drive voltage (VLmin) of the drive voltage (VL) applied to each series unit (C1) to (C12) according to the dimming degree, the reference Two reference voltages, that is, a maximum reference voltage (VR1) and a minimum reference voltage (VR2) are provided in the voltage circuit (4). The maximum reference voltage (VR1) and the minimum reference voltage (VR2) are obtained by dividing the power supply voltage (VCC) by high-precision resistors (Ra to Rd) connected to the ground (G). You can do it.
上述したモニタ信号の電圧（Ｖ１）〜（Ｖ１２）はそれぞれに、最大基準電圧（ＶＲ１）および最小基準電圧（ＶＲ２）と比較される。この動作は、図２に示すような、汎用のコンパレータからなる比較回路（３）によりなされる。 The monitor signal voltages (V1) to (V12) are compared with the maximum reference voltage (VR1) and the minimum reference voltage (VR2), respectively. This operation is performed by a comparison circuit (3) composed of a general-purpose comparator as shown in FIG.
モニタ信号の電圧（Ｖ１）を例にとって説明すると、この電圧（Ｖ１）は、比較回路（３）内でウインドウコンパレータを構成している２つのコンパレータ（ＣＰ１−１）および（ＣＰ１−２）にてそれぞれ最大基準電圧（ＶＲ１）および最小基準電圧（ＶＲ２）と比較される。比較回路（３）の出力電圧は、正常な場合をＨレベル、ＬＥＤ破壊時をＬレベルとして出力端子から出力される。このとき、モニタ信号の電圧（Ｖ１）レベルが最大基準電圧（ＶＲ１）と最小基準電圧（ＶＲ２）との間に入り、その出力電圧（０１）がＨレベルとなった場合を全てのＬＥＤ素子が正常状態にあると判定する。逆に、その出力電圧（０１）がＬレベルになった場合は、オープン破壊やショート破壊が発生したものと判定する。このオープン破壊やショート破壊の詳細については、後述する。 The voltage (V1) of the monitor signal will be described as an example. This voltage (V1) is generated by the two comparators (CP1-1) and (CP1-2) constituting the window comparator in the comparison circuit (3). Each is compared with the maximum reference voltage (VR1) and the minimum reference voltage (VR2). The output voltage of the comparison circuit (3) is output from the output terminal with the H level when normal and the L level when the LED is broken. At this time, when the voltage (V1) level of the monitor signal is between the maximum reference voltage (VR1) and the minimum reference voltage (VR2) and the output voltage (01) becomes H level, all the LED elements Determined to be in a normal state. On the contrary, when the output voltage (01) becomes L level, it is determined that an open breakdown or a short breakdown has occurred. Details of the open break and short break will be described later.
以上の態様は、直列単位（Ｃ１）についての破壊検知例であるが、他の直列単位（Ｃ２）〜（Ｃ１２）も同様に適用される。したがって、各直列単位（Ｃ２）〜（Ｃ１２）に対応する各モニタ信号の電圧（Ｖ２）〜（Ｖ１２）を最大基準電圧（ＶＲ１）および最小基準電圧（ＶＲ２）と比較することにより、同様にＬＥＤ破壊が検知される。 Although the above aspect is an example of the destruction detection about the serial unit (C1), the other serial units (C2) to (C12) are similarly applied. Therefore, by comparing the voltage (V2) to (V12) of each monitor signal corresponding to each series unit (C2) to (C12) with the maximum reference voltage (VR1) and the minimum reference voltage (VR2), the LED similarly Destruction is detected.
そして、比較回路（３）からの各出力電圧（０１）〜（０１２）は、次段の１２入力１出力ＡＮＤ回路からなる破壊判定回路（５）に入力される。したがって、この破壊判定回路（５）では、入力する出力電圧（０１）〜（０１２）の内、一つでもＬレベルがあれば破壊の判定がなされる。さらに、この破壊判定回路（５）からの破壊判定出力電圧（Ｌレベル）は、次段の駆動回路（６）を経由して破壊表示・破壊警告音処理回路（７）にて処理され、破壊表示用素子、例えばＬＥＤ（８）を点灯させ、あるいは破壊警告ブザー（９）を作動させる。 The output voltages (01) to (012) from the comparison circuit (3) are input to the destruction determination circuit (5) including a 12-input 1-output AND circuit in the next stage. Therefore, in this destruction determination circuit (5), if at least one of the input output voltages (01) to (012) is at L level, the destruction is determined. Further, the destruction determination output voltage (L level) from the destruction determination circuit (5) is processed by the destruction display / destruction warning sound processing circuit (7) via the drive circuit (6) in the next stage, The display element, for example, the LED (8) is turned on, or the destruction warning buzzer (9) is activated.
図３には、図２の直列単位（Ｃ1）に印加する駆動電圧（ＶＬ）と、導通検出素子であるＬＥＤ素子（Ｄ１−９）のモニタ信号の電圧（Ｖ１）との一般的関係が示されている。図３における直線Ａ〜Ｅはそれぞれに、以下のケースに該当する。
ａ．直線（Ａ）：直列単位（Ｃ１）の全てのＬＥ素子（Ｄ１−１）〜（Ｄ１−９）がオープン破壊もショート破壊も無い、すなわち正常な点灯状態のケース。
ｂ．直線（Ｂ）：ＬＥＤ素子群（Ｄ１−１）〜（Ｄ１−８）のいずれかの素子がショート破壊したケース。
ｃ．直線（Ｃ）：検出素子を兼用するＬＥＤ（Ｄ１−９）がオープン破壊したケース。
ｄ．直線（Ｄ）：ＬＥＤ素子群（Ｄ１−１）〜（Ｄ１−８）のいずれかの素子がオープン破壊したケース。
ｅ．直線（Ｅ）：検出素子を兼用するＬＥＤ素子（Ｄ１−９）がショート破壊したケース。
FIG. 3 shows a general relationship between the drive voltage (VL) applied to the series unit (C1) of FIG. 2 and the monitor signal voltage (V1) of the LED element (D1-9) which is a continuity detecting element. Has been. The straight lines A to E in FIG. 3 correspond to the following cases, respectively.
a. Straight line (A): A case where all the LE elements (D1-1) to (D1-9) in the series unit (C1) are free from open breakdown and short-circuit breakdown, that is, in a normal lighting state.
b. Straight line (B): a case in which any one of the LED element groups (D1-1) to (D1-8) is short-circuited.
c. Straight line (C): A case where the LED (D1-9), which also serves as a detection element, is open broken.
d. Straight line (D): a case where any one of the LED element groups (D1-1) to (D1-8) is open broken.
e. Straight line (E): A case where the LED element (D1-9), which also serves as a detection element, is short-circuited.
この図３から、以下のａおよびｂの判定がなされる。
ａ．直線（Ｂ）および（Ｃ）におけるモニタ信号の電圧（Ｖ１）は、全調光範囲（駆動電圧ＶＬ）で最大基準電圧（ＶＲ１）を上回っている。これに対して、正常状態のモニタ信号の電圧（Ｖ１）は、直線（Ａ）で示すように、全調光範囲（駆動電圧ＶＬ）で、この最大基準電圧（ＶＲ１）と最小基準電圧（ＶＲ２）の間にある。このことから、モニタ信号の電圧（Ｖ１）と最大基準電圧（ＶＲ１）とを比較し、モニタ信号の電圧（Ｖ１）＞最大基準電圧（ＶＲ１）を満足する場合には、直線（Ｂ）、（Ｃ）のいずれかのケースであることが検知できる。なお、直線（Ｂ）のケースが発生する確率は、他の直線（Ｃ）、（Ｄ）、および直線（Ｅ）のケースに比べて、極めて低い。
ｂ．一方、直線（Ｄ）、直線（Ｅ）のケースでは、モニタ信号の電圧（Ｖ１）は、全調光範囲（駆動電圧ＶＬ）で最小基準電圧（ＶＲ２）を下回っている。このことから、モニタ信号の電圧（Ｖ１）と最小基準電圧（ＶＲ２）とを比較し、モニタ信号の電圧（Ｖ１）＜最小基準電圧（ＶＲ２）を満足する場合には、直線（Ｄ）、あるいは直線（Ｅ）のいずれかのケースであることが検知できる。
From FIG. 3, the following determinations a and b are made.
a. The voltage (V1) of the monitor signal in the straight lines (B) and (C) exceeds the maximum reference voltage (VR1) in the entire dimming range (drive voltage VL). On the other hand, the voltage (V1) of the monitor signal in the normal state is the maximum reference voltage (VR1) and the minimum reference voltage (VR2) in the entire dimming range (drive voltage VL) as shown by the straight line (A). ) Therefore, the voltage (V1) of the monitor signal is compared with the maximum reference voltage (VR1), and when the monitor signal voltage (V1)> the maximum reference voltage (VR1) is satisfied, the straight lines (B), ( It can be detected that the case is any one of C). Note that the probability of occurrence of the straight line (B) case is extremely low compared to the cases of the other straight lines (C), (D), and the straight line (E).
b. On the other hand, in the case of the straight line (D) and the straight line (E), the voltage (V1) of the monitor signal is lower than the minimum reference voltage (VR2) in the entire dimming range (drive voltage VL). Therefore, the voltage (V1) of the monitor signal is compared with the minimum reference voltage (VR2), and when the voltage (V1) of the monitor signal <minimum reference voltage (VR2) is satisfied, the straight line (D) or It can be detected that the case is one of the straight lines (E).
以上に述べた第一の態様で特徴的なことは、各直列単位（Ｃ１）〜（Ｃ１２）において、一部のＬＥＤ素子が検出回路へモニタ信号を出力する導通検知素子（２）として兼用され、且つ該検出回路には、各直列単位（Ｃ１）〜（Ｃ１２）に印加される駆動電源の電圧（ＶＬ）の変化に対応できる機能が付与されていることに在る。こうすることにより、照射光量を変化させる調光モードにおいて、ＬＥＤの駆動電圧が変化しても、ＬＥＤ破壊が検知できる。また、一部のＬＥＤ素子を導通検知素子として兼用しているので、フォトカプラのような追加的検出素子を必要とせず、構成が簡略化される。 What is characteristic in the first aspect described above is that, in each of the series units (C1) to (C12), some LED elements are also used as continuity detection elements (2) for outputting a monitor signal to the detection circuit. In addition, the detection circuit is provided with a function capable of responding to changes in the voltage (VL) of the drive power supply applied to each of the series units (C1) to (C12). By doing so, even in the dimming mode in which the irradiation light quantity is changed, the LED breakage can be detected even if the LED drive voltage changes. In addition, since some LED elements are also used as continuity detection elements, an additional detection element such as a photocoupler is not required, and the configuration is simplified.
上述の第一の態様においては、ＬＥＤ素子間の電圧―電流特性の違い、素子のばらつき、さらには駆動電圧の影響等で、図４に示すように、直線（Ａ）と直線（Ｂ）の間隔が接近してしまうことがある。この場合には、固定された最大基準電圧（ＶＲ１）では両者を区別するのが困難になる。この区別が必要なときは、以下に述べる第二の態様を採用される。 In the first aspect described above, the difference between the voltage-current characteristics between the LED elements, the element variation, and the influence of the drive voltage, etc., as shown in FIG. 4, the straight lines (A) and (B) The interval may approach. In this case, it becomes difficult to distinguish the two with the fixed maximum reference voltage (VR1). When this distinction is necessary, the second mode described below is adopted.
本発明の第二の態様にあっては、図４に示すように、最大基準電圧（ＶＲ１）を各直列単位（Ｃ１）〜（Ｃ１２）に印加される駆動電圧（ＶＬ）に連動した最大側可変基準電圧（ＶＲ３）に変更する。 In the second aspect of the present invention, as shown in FIG. 4, the maximum reference voltage (VR1) is linked to the drive voltage (VL) applied to each series unit (C1) to (C12). Change to variable reference voltage (VR3).
この際、この最大側可変基準電圧（ＶＲ３）は、直線（Ａ）と直線（Ｂ）のケースを判別するために、同図に示すように全調光範囲で、直線（Ａ）と直線（Ｂ）のほぼ中間の値に設定する。図４の場合のように、直線（Ａ）と直線（Ｂ）が互いに平行な場合には、駆動電圧（ＶＬ）を高精度の抵抗で抵抗分圧するだけで、直線（Ａ）と直線（Ｂ）のほぼ中間に最大側可変基準電圧（ＶＲ３）を容易に設定できる。また、直線（Ａ）と直線（Ｂ）が曲線の場合には、各曲線の形状に応じて、公知のオペアンプ等による曲線補正回路を利用して、曲線状の最大側可変基準電圧（ＶＲ３）を直線（Ａ）と直線（Ｂ）のほぼ中間に入るように設定すればよい。これにともない、図１および図２の比較回路（３）では、最大基準電圧（ＶＲ１）のみ最大側可変基準電圧（ＶＲ３）に変更されるとともに、基準電圧回路（４）の最大基準電圧（ＶＲ１）側の電源端子（ＶＣＣ）のみ駆動電圧（ＶＬ）に変更される。 At this time, the maximum variable reference voltage (VR3) is used to determine the case of the straight line (A) and the straight line (B), as shown in FIG. B) is set to an approximately middle value. As in the case of FIG. 4, when the straight line (A) and the straight line (B) are parallel to each other, the drive voltage (VL) is simply divided by a resistor with high precision, and the straight line (A) and the straight line (B ) Can be easily set to the maximum variable reference voltage (VR3). Further, when the straight line (A) and the straight line (B) are curves, a curved maximum variable reference voltage (VR3) is used by using a curve correction circuit such as a known operational amplifier according to the shape of each curve. May be set so as to fall approximately between the straight line (A) and the straight line (B). Accordingly, in the comparison circuit (3) of FIGS. 1 and 2, only the maximum reference voltage (VR1) is changed to the maximum variable reference voltage (VR3), and the maximum reference voltage (VR1) of the reference voltage circuit (4) is changed. ) Side power supply terminal (VCC) only is changed to the drive voltage (VL).
同様にして、他の直列単位列（Ｃ２）〜（Ｃ１２）についても、最大基準電圧（ＶＲ１）を最大側可変基準電圧（ＶＲ３）に変更することにより、ＬＥＤ破壊が検知される。 Similarly, with respect to the other series unit columns (C2) to (C12), LED breakdown is detected by changing the maximum reference voltage (VR1) to the maximum variable reference voltage (VR3).
この第二の態様では、ショート破壊とオープン破壊は一括検知される。すなわち、直線（Ｂ）と直線（Ｃ）は共に、最大側可変基準電圧（ＶＲ３）の上側に位置しているので、ショート破壊（直線（Ｂ））とオープン破壊（直線（Ｃ））の区別はされない。同様に、直線（Ｄ）と直線（Ｅ）は共に最小基準電圧（ＶＲ２）の下側に位置しているので、両者も互いに区別されない。これらの破壊モード毎に区別が必要な際には、以下に述べる第三の態様が採用される。 In this second aspect, short breaks and open breaks are collectively detected. That is, since both the straight line (B) and the straight line (C) are located on the upper side of the maximum variable reference voltage (VR3), the distinction between short-circuit breakdown (straight line (B)) and open breakdown (straight line (C)). Not done. Similarly, since both the straight line (D) and the straight line (E) are located below the minimum reference voltage (VR2), they are not distinguished from each other. When distinction is necessary for each of these destruction modes, the third mode described below is adopted.
本発明の第三の態様にあっては、図５において、最大基準電圧（ＶＲ１）を維持しながら、その下側にさらに最大側可変基準電圧（ＶＲ３）を設け、且つ最小基準電圧（ＶＲ２）を維持しながら、その下側にさらに最小側可変基準電圧（ＶＲ４）が追加・併用される。この際、最小側可変基準電圧（ＶＲ４）の電圧レベルは、全調光範囲で直線（Ｄ）と直線（Ｅ）との中間に設ける。最大側可変基準電圧（ＶＲ３）については、第二の態様の場合と同じである。 In the third aspect of the present invention, in FIG. 5, while maintaining the maximum reference voltage (VR1), a maximum variable reference voltage (VR3) is further provided below the minimum reference voltage (VR2). The minimum side variable reference voltage (VR4) is further added and used in the lower side while maintaining the above. At this time, the voltage level of the minimum variable reference voltage (VR4) is provided between the straight line (D) and the straight line (E) in the entire dimming range. The maximum variable reference voltage (VR3) is the same as in the second embodiment.
要するに、第三の態様では、最大基準電圧（ＶＲ１）および最小基準電圧（ＶＲ２）に加えて、最大側可変基準電圧（ＶＲ３）と最小側可変基準電圧（ＶＲ４）を併用し、これら４個の基準電圧を組み込んだ比較回路が採用される。これにより、破壊モード（直線（Ｂ）〜直線（Ｅ））毎の判別が可能になり、より高精度な破壊検出が実現される。 In short, in the third aspect, in addition to the maximum reference voltage (VR1) and the minimum reference voltage (VR2), the maximum variable reference voltage (VR3) and the minimum variable reference voltage (VR4) are used in combination. A comparison circuit incorporating a reference voltage is employed. Thereby, it becomes possible to discriminate for each destruction mode (straight line (B) to straight line (E)), and more accurate destruction detection is realized.
この場合の検知回路の例は図６に示されている。この例では、４段のコンパレータ（ＣＰ１−１）〜（ＣＰ１−４）と３個のアナログスイッチ（ＳＷ１）〜（ＳＷ３）とからなる比較回路（３）、ならびに最大基準電圧（ＶＲ1）および最小基準電圧（ＶＲ2）に加えて、ＬＥＤ駆動電圧（ＶＬ）を高精度の４個の抵抗（Ｒｅ〜Ｒｈ）にて抵抗分圧した最大側可変基準電圧（ＶＲ３）および最小側可変基準電圧（ＶＲ４）からなる基準電圧回路（４）により実現できる。 An example of the detection circuit in this case is shown in FIG. In this example, a comparator circuit (3) comprising four stages of comparators (CP1-1) to (CP1-4) and three analog switches (SW1) to (SW3), a maximum reference voltage (VR1) and a minimum In addition to the reference voltage (VR2), the LED variable voltage (VR3) and the minimum variable reference voltage (VR4) are obtained by dividing the LED driving voltage (VL) by four resistors (Re to Rh) with high accuracy. The reference voltage circuit (4) can be realized.
この図６の回路では、各破壊モード（直線（Ｂ）〜直線（Ｅ））の破壊状態が４段のコンパレータ（ＣＰ１−１）〜（ＣＰ１−４）から出力されるので、破壊モード毎の識別が可能になる。具体的に言えば、初段のコンパレータ（ＣＰ１−１）の出力（０Ｐ１）がＬレベルの場合には、直線（Ｅ）に関するショート破壊と識別でき、二段目のコンパレータ（ＣＰ１−２）の出力（０Ｐ２）がＬレベルの場合には、直線（Ｄ）に関するオープン破壊と識別できる。同様に、３段目のコンパレータ（ＣＰ１−３）の出力（０Ｐ３）がＬレベルの場合には、正常と識別でき、逆にＨレベルの場合には、直線（Ｂ）に関するショート破壊あるいは直線（Ｃ）に関するオープン破壊と識別できる。さらに、４段目のコンパレータ（ＣＰ１−４）の出力（０Ｐ４）がＬレベルの場合には、直線（Ｂ）に関するショート破壊と識別でき他方、Ｈレベルの場合には直線（Ｃ）に関するオープン破壊と識別できる。その結果、全ての破壊モード毎が検知され、より高精度なＬＥＤ破壊検出が実現する。 In the circuit of FIG. 6, the destruction state of each destruction mode (straight line (B) to straight line (E)) is output from the four-stage comparators (CP1-1) to (CP1-4). Identification becomes possible. Specifically, when the output (0P1) of the first-stage comparator (CP1-1) is at the L level, it can be identified as a short-circuit breakdown related to the straight line (E), and the output of the second-stage comparator (CP1-2). When (0P2) is at the L level, it can be identified as an open break with respect to the straight line (D). Similarly, when the output (0P3) of the third-stage comparator (CP1-3) is at L level, it can be identified as normal, and conversely, when it is at H level, a short break or straight line (B C) can be distinguished from open destruction. Further, when the output (0P4) of the comparator (CP1-4) at the fourth stage is at the L level, it can be distinguished from a short-circuit failure with respect to the straight line (B). Can be identified. As a result, every destruction mode is detected, and more accurate LED destruction detection is realized.
さらに、比較回路（３）から出力される、破壊モード毎の出力信号を利用して検出時の破壊内容に応じて多色ＬＥＤ素子あるいは複数色のＬＥＤ素子を用い、破壊モード毎に色を変えて表示し、あるいは破壊内容に応じて圧電ブザー等の警告音を変えることにより、さらに高機能化が図られる。 Furthermore, using the output signal for each destruction mode output from the comparison circuit (3), a multi-color LED element or a multi-color LED element is used according to the destruction contents at the time of detection, and the color is changed for each destruction mode. By displaying a warning sound such as a piezoelectric buzzer or the like according to the contents of destruction, the function can be further enhanced.
そして、上記の回路を他の直列単位（Ｃ２）〜（Ｃ１２）に適用することにより、全ての直列単位毎に全ての破壊モードについてオープン破壊とショート破壊を区別しながら検知できる。 Then, by applying the above circuit to the other series units (C2) to (C12), it is possible to detect all breakdown modes while distinguishing open breakdown and short breakdown for every series unit.
図７には、本発明のＬＥＤ破壊検出装置を組込んだ検査用のライン状ＬＥＤ照明装置（１０）の斜視図が示されている。この例では、パネル前面に破壊表示素子（８）、破壊警告ブザー（９）、調光（光量調整）ボリューム（１１）、および、ライン状のＬＥＤ照射部（１２）が設けてある。このＬＥＤ照射部（１２）は、図１のＬＥＤ素子直並列回路に対応し、ここでは、横２段に直列単位（Ｃ１）および（Ｃ２）が配されている。 FIG. 7 shows a perspective view of a line LED illumination device (10) for inspection incorporating the LED breakage detection device of the present invention. In this example, a destructive display element (8), a destructive warning buzzer (9), a dimming (light quantity adjustment) volume (11), and a line-shaped LED irradiation section (12) are provided on the front surface of the panel. This LED irradiation part (12) respond | corresponds to the LED element serial / parallel circuit of FIG. 1, and here, the serial units (C1) and (C2) are arranged by two horizontal steps.
本発明において、各直列単位におけるＬＥＤの接続数、および直列単位の並列配置数は、最終製品の仕様に応じて任意に設定すればよいことは言うまでもない。また、導通検知素子（２）についても必ずしも、各直列単位の最下段に固定する必要はなく、印加電圧あるいは検知方法に応じて選定すればよい。 In the present invention, it goes without saying that the number of LEDs connected in each series unit and the number of parallel arrangements in series units may be arbitrarily set according to the specifications of the final product. Further, the conduction detecting element (2) is not necessarily fixed to the lowest stage of each series unit, and may be selected according to the applied voltage or the detection method.
本発明のＬＥＤ破壊検出装置は、オープン破壊のみならずショート（ショート）破壊が検知できるので、画像処理照明用や光学機器照明用のみならず信号機等の屋外表示灯用あるいは商品展示用等の屋内照明用あるいは医療用照明装置の用途にも適用できる。 Since the LED breakage detection apparatus of the present invention can detect not only open breakage but also short (short) breakage, it can be used not only for image processing lighting and optical equipment lighting but also for outdoor indicator lights such as traffic lights or for display of products. It can also be applied to lighting or medical lighting devices.
１ ＬＥＤ破壊検出部
２ 導通検知素子
３ 比較回路
４ 基準電圧回路
５ 破壊判定回路
６ 駆動回路
７ 破壊表示・警告音処理回路
８ 破壊表示素子
９ 破壊警告ブザー
１０ 本発明のＬＥＤ破壊検出装置を組込んだ検査用のライン状ＬＥＤ照明装置
１１ 調光（光量調節）ボリューム
１２ ライン状ＬＥＤ素子群
Ｃ１〜Ｃ１２ ＬＥＤ素子群の直列接続単位（各列）
Ｄ１−１〜Ｄ１２−９ 各直列接続単位を構成するＬＥＤ素子群
Ｖ１〜Ｖ１２ モニタ信号
０１〜０１２ 出力信号
Ｒ１〜Ｒ１２ 電流制限抵抗
ＶＲ１ 最大基準電圧（固定電圧）
ＶＲ２ 最小側基準電圧（固定電圧）
ＶＲ３ 最大側可変基準電圧
ＶＲ４ 最小側可変基準電圧
ＶＬ ＬＥＤ駆動電圧
Ｇ グランド（アース）
DESCRIPTION OF SYMBOLS 1 LED destruction detection part 2 Continuity detection element 3 Comparison circuit 4 Reference voltage circuit 5 Destruction determination circuit 6 Drive circuit 7 Destruction display / warning sound processing circuit 8 Destruction display element 9 Destruction warning buzzer 10 The LED destruction detection apparatus of the present invention is incorporated Line LED illumination device 11 for inspection 11 Dimming (light quantity adjustment) volume 12 Line LED element groups C1 to C12 Series connection units of LED element groups (each row)
D1-1 to D12-9 LED element groups constituting each series connection unit V1 to V12 Monitor signals 01 to 012 Output signals R1 to R12 Current limiting resistor VR1 Maximum reference voltage (fixed voltage)
VR2 Minimum side reference voltage (fixed voltage)
VR3 Maximum variable reference voltage VR4 Minimum variable reference voltage VL LED drive voltage G Ground (earth)
Claims (7)
The LED breakage detection device according to any one of claims 1 to 6, which is useful for a lighting apparatus for image processing or equipment inspection.
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| US9089023B2 (en) | 2013-05-17 | 2015-07-21 | Rohm Co., Ltd. | Driving circuit of light emitting element, and light emitting device and electronic apparatus including the light emitting element |
| US9177508B2 (en) | 2011-03-24 | 2015-11-03 | Rohm Co., Ltd. | Light emitting apparatus |
| JP5947964B1 (en) * | 2015-08-03 | 2016-07-06 | Piaa株式会社 | LED lamp sequential circuit |
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| JP2006210219A (en) * | 2005-01-31 | 2006-08-10 | Koito Mfg Co Ltd | Lighting control circuit of vehicular lighting fixture |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010123273A (en) * | 2008-11-17 | 2010-06-03 | Ccs Inc | Led lighting device |
| JP2013012487A (en) * | 2009-10-02 | 2013-01-17 | Lecip Holdings Corp | Light-emitting diode illumination circuit and luminaire |
| US8653742B2 (en) | 2011-03-08 | 2014-02-18 | Rohm Co., Ltd. | Control circuit of switching power supply for driving light emitting elements, and light emitting device and electronic apparatus using the same |
| US9177508B2 (en) | 2011-03-24 | 2015-11-03 | Rohm Co., Ltd. | Light emitting apparatus |
| CN103018256A (en) * | 2012-12-13 | 2013-04-03 | 清华大学深圳研究生院 | LED (light-emitting diode) defect detecting system |
| CN103018256B (en) * | 2012-12-13 | 2014-08-13 | 清华大学深圳研究生院 | LED (light-emitting diode) defect detecting system |
| US9089023B2 (en) | 2013-05-17 | 2015-07-21 | Rohm Co., Ltd. | Driving circuit of light emitting element, and light emitting device and electronic apparatus including the light emitting element |
| JP5947964B1 (en) * | 2015-08-03 | 2016-07-06 | Piaa株式会社 | LED lamp sequential circuit |
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| JP4791299B2 (en) | 2011-10-12 |
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