JPH08194448A - Display device - Google Patents
Display deviceInfo
- Publication number
- JPH08194448A JPH08194448A JP629595A JP629595A JPH08194448A JP H08194448 A JPH08194448 A JP H08194448A JP 629595 A JP629595 A JP 629595A JP 629595 A JP629595 A JP 629595A JP H08194448 A JPH08194448 A JP H08194448A
- Authority
- JP
- Japan
- Prior art keywords
- series
- voltage
- constant current
- light emitting
- light
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
- Control Of El Displays (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、光源として発光ダイオ
ードを組込んだ表示装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device incorporating a light emitting diode as a light source.
【０００２】[0002]
【従来の技術】周知のように、高層建物や送電鉄塔等に
は、夜間飛行の航空機等に危険場所である旨を知らせる
ための航空障害灯が設けられている。また、道路工事現
場等においても、夜間通行者等の安全を確保するため
に、標識灯を設置することがよく行われている。2. Description of the Related Art As is well known, high-rise buildings, power transmission towers and the like are provided with aviation obstacle lights for informing night-flying aircraft and the like that they are dangerous areas. Also, at road construction sites and the like, sign lamps are often installed to ensure the safety of people who pass by at night.
【０００３】このような目的に供せられる、いわゆる表
示装置の光源としては、放電管や白熱灯や発光ダイオー
ド等が用いられているが、最近では、消費電力が少ない
こと、発光体そのものから所定の発光色が得られること
などの理由から、発光ダイオードが多用される傾向にあ
る。A discharge tube, an incandescent lamp, a light emitting diode and the like are used as a light source of a so-called display device which is provided for such a purpose. However, recently, the power consumption is low and the light emitting body itself has a predetermined value. The light emitting diode tends to be frequently used for the reason that the emission color can be obtained.
【０００４】ところで、光源として発光ダイオードを組
み込んだ表示装置では、必要な表示面積、形状および光
量を得るために、通常、複数の発光ダイオードを直列接
続した直列要素を複数並列に接続し、これを全波整流器
等で構成された直流電源に接続したものとなっている。By the way, in a display device incorporating a light emitting diode as a light source, in order to obtain a necessary display area, shape and light amount, a plurality of series elements in which a plurality of light emitting diodes are connected in series are usually connected in parallel, and the elements are connected in parallel. It is connected to a DC power supply composed of a full-wave rectifier.
【０００５】しかしながら、上記のように構成された従
来の表示装置にあっても次のような問題があった。すな
わち、光源を構成している発光ダイオードに流れる電流
は、電源電圧の変動によって変動し、電源電圧の変動率
以上の割合で変動するため、光量が大幅に変動する。こ
のような光量変動は、表示装置としての信頼性低下を招
くことになり、好ましいことではない。However, even the conventional display device configured as described above has the following problems. That is, the current flowing through the light emitting diode that constitutes the light source fluctuates due to fluctuations in the power supply voltage, and fluctuates at a rate equal to or higher than the fluctuation rate of the power supply voltage. Such a variation in the amount of light causes a decrease in reliability as a display device, and is not preferable.
【０００６】そこで、電源電圧の変動に伴う光量変動を
抑制するために、上述した直列要素と直列に抵抗値の大
きな抵抗器を接続する方式を採用している。しかし、こ
の方式を採用すると、効率が極端に悪化するばかりでな
く、電源電圧の変動に伴って発光ダイオードに流れる電
流が変化することには変わりないので、必ずしも好まし
い結果は得られていない。Therefore, in order to suppress the fluctuation of the light amount due to the fluctuation of the power supply voltage, a method of connecting a resistor having a large resistance value in series with the above-mentioned series element is adopted. However, when this method is adopted, not only the efficiency is extremely deteriorated but also the current flowing through the light emitting diode is changed in accordance with the fluctuation of the power supply voltage, and therefore, the preferable result is not always obtained.
【０００７】また、従来の装置にあっては、電源電圧が
高くなる方向に変動すると、各発光ダイオードに流れる
電流が増加し、これが寿命特性に悪影響を与える問題も
あった。Further, in the conventional device, when the power supply voltage fluctuates in the direction of increasing, the current flowing through each light emitting diode increases, which has a problem that the life characteristics are adversely affected.
【０００８】[0008]
【発明が解決しようとする課題】上述の如く、光源とし
て発光ダイオードを組込んだ従来の表示装置にあって
は、電源電圧の変動に伴って表示性能が変化するばかり
か、電源電圧の変動に起因して寿命が低下するという問
題があった。As described above, in the conventional display device incorporating the light emitting diode as the light source, not only the display performance changes in accordance with the fluctuation of the power supply voltage but also the fluctuation of the power supply voltage. As a result, there is a problem that the life is shortened.
【０００９】そこで本発明は、電源電圧の変動に左右さ
れることなく、各発光ダイオードに流れる電流の値を一
定に保持でき、もって表示性能の安定化と長寿命化とを
実現できる表示装置を提供することを目的としている。Therefore, the present invention provides a display device capable of maintaining a constant value of the current flowing through each light emitting diode without being affected by fluctuations in the power supply voltage, and thus realizing stable display performance and long life. It is intended to be provided.
【００１０】[0010]
【課題を解決するための手段】上記目的を達成するため
に、本発明は、発光ダイオードを複数直列接続した直列
要素からなる光源を備えた表示装置において、前記直列
要素と直列に定電流素子を接続してなることを特徴とし
ている。なお、定電流素子として、定電流ダイオードを
使用することが好ましい。In order to achieve the above object, the present invention provides a display device including a light source comprising a series element in which a plurality of light emitting diodes are connected in series, and a constant current element in series with the series element. It is characterized by being connected. A constant current diode is preferably used as the constant current element.
【００１１】[0011]
【作用】電源電圧が変動した場合であっても、直列要素
と直列に接続された定電流素子の機能によって、各発光
ダイオードに流れる電流の値が常に一定に保持される。
したがって、電源電圧の変動に左右されることなく、常
に一定の表示性能を発揮させることができ、しかも各発
光ダイオードに規定以上の電流が流れるのを防止できる
ので、長寿命化も図ることが可能となる。Even if the power supply voltage fluctuates, the value of the current flowing through each light emitting diode is always kept constant by the function of the constant current element connected in series with the series element.
Therefore, a constant display performance can always be exhibited without being affected by fluctuations in the power supply voltage, and moreover, it is possible to prevent a current exceeding a specified value from flowing in each light emitting diode, so that a long life can be achieved. Becomes
【００１２】[0012]
【実施例】以下、図面を参照しながら実施例を説明す
る。図１には本発明の一実施例に係る表示装置の回路構
成図が示されている。同図において、１はたとえばダイ
オードブリッジ回路と平滑リアクトルと平滑コンデンサ
とを組合せて構成された全波整流電源回路を示してい
る。この全波整流電源回路１は、その交流入力端子２
ａ，２ｂがたとえば100 Ｖの交流電源３に接続され、直
流出力端子４ａ，４ｂ間に141 Ｖの直流電圧を発生す
る。そして、全波整流電源回路１の直流出力端子４ａ，
４ｂ間には複数、この例ではたとえば４４個の発光ユニ
ット５-1，５-2，…５-44 が並列に接続されている。Embodiments will be described below with reference to the drawings. FIG. 1 shows a circuit configuration diagram of a display device according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a full-wave rectification power supply circuit configured by combining, for example, a diode bridge circuit, a smoothing reactor, and a smoothing capacitor. This full-wave rectification power supply circuit 1 has its AC input terminal 2
a and 2b are connected to an AC power source 3 of 100 V, for example, and a DC voltage of 141 V is generated between the DC output terminals 4a and 4b. Then, the DC output terminal 4a of the full-wave rectification power supply circuit 1,
A plurality of, for example, 44 light emitting units 5 -1 , 5 -2 , ... 5 -44 in this example are connected in parallel between 4b.
【００１３】各発光ユニット５-1，５-2，…５-44 は、
それぞれ発光ダイオード６を複数個、この例ではたとえ
ば１８個直列に接続してなる直列要素７と、この直列要
素７に対して直列に接続された定電流ダイオード（定電
流素子）８および抵抗器９とで構成されている。なお、
定電流ダイオード８としては、その飽和電流値（定電流
値）が発光ダイオード６の定格電流値に近いものが用い
られている。Each of the light emitting units 5 -1 , 5 -2 , ... 5 -44 is
A plurality of light emitting diodes 6, respectively, for example, 18 in this example, are connected in series, a series element 7, a constant current diode (constant current element) 8 and a resistor 9 connected in series to the series element 7. It consists of and. In addition,
As the constant current diode 8, a diode whose saturation current value (constant current value) is close to the rated current value of the light emitting diode 6 is used.
【００１４】なお、抵抗器９は雷サージ等が侵入した時
に定電流ダイオード８や発光ダイオード６が過電流破壊
するのを防ぐためのもので、10Ω程度と小さい値の抵抗
値でよく、効率に与える影響はほとんどない。たとえ
ば、電流が20ｍＡで抵抗値が10Ωであると、4 ｍＷの消
費電力となり、実施例のように４４個の抵抗器を使用し
た場合には、全体の損失が176 ｍＷと低い。The resistor 9 is for preventing the constant current diode 8 and the light emitting diode 6 from being destroyed by an overcurrent when a lightning surge or the like enters, and a resistance value as small as about 10 Ω is sufficient, and the efficiency is improved. It has almost no effect. For example, when the current is 20 mA and the resistance value is 10 Ω, the power consumption is 4 mW, and when 44 resistors are used as in the embodiment, the total loss is 176 mW.
【００１５】このような構成であると、交流電源３を投
入することによって、792 個の発光ダイオード６を一斉
に発光させることができ、これによって表示装置として
の機能を発揮させることができる。With such a structure, by turning on the AC power supply 3, the 792 light emitting diodes 6 can be made to emit light all at once, whereby the function as a display device can be exerted.
【００１６】この場合、交流電源３の出力電圧が変動す
ると、直流出力端子４ａ，４ｂ間の電圧は、交流側電圧
変動幅の約1.4 倍の変動幅で変化する。たとえば交流電
源３の出力電圧が10Ｖ変化すると、直流出力端子４ａ，
４ｂ間の電圧が約14Ｖ変化する。In this case, when the output voltage of the AC power supply 3 changes, the voltage between the DC output terminals 4a and 4b changes with a fluctuation width of about 1.4 times the fluctuation width of the AC side voltage. For example, if the output voltage of the AC power supply 3 changes by 10 V, the DC output terminal 4a,
The voltage across 4b changes by about 14V.
【００１７】しかし、この実施例においては、各発光ユ
ニット５-1，５-2，…５-44 を構成している直列要素７
と直列に定電流ダイオード８を設けているので、この定
電流ダイオード８の両端電圧Ｖが、ピンチオフ電圧Ｐp
以上で、ブレークダウン電圧Ｖｂ未満である限り、各直
列要素７に流れる電流が一定の値に保持される。すなわ
ち、交流電源３の電圧変動に左右されることなく、各直
列要素７に流れる電流が一定値に保持される。したがっ
て、電源電圧の変動に左右されることなく、常に一定の
光量を維持でき、しかも各発光ダイオード６に規定以上
の電流が流れるのを防止できるので、長寿命化も図るこ
とが可能となる。However, in this embodiment, the series element 7 constituting each of the light emitting units 5 -1 , 5 -2 , ... 5 -44.
Since the constant current diode 8 is provided in series with the constant current diode 8, the voltage V across the constant current diode 8 is the pinch-off voltage Pp.
As described above, the current flowing through each series element 7 is maintained at a constant value as long as it is less than the breakdown voltage Vb. That is, the current flowing through each series element 7 is maintained at a constant value without being affected by the voltage fluctuation of the AC power supply 3. Therefore, a constant amount of light can always be maintained without being affected by fluctuations in the power supply voltage, and moreover, a current exceeding a specified value can be prevented from flowing in each light emitting diode 6, so that the life can be extended.
【００１８】なお、直列要素７に流すべき電流値に比べ
て定電流ダイオード８の飽和電流値が小さいときには、
図１中に２点鎖線で示すように、各発光ユニット５-1，
５-2，…５-44 における定電流ダイオード８と抵抗器９
との直列回路と並列に、定電流ダイオード８と抵抗器９
との直列回路を１組または複数組並列に接続すればよ
い。この場合、抵抗器９を共用することもできる。When the saturation current value of the constant current diode 8 is smaller than the current value to be passed through the series element 7,
As shown by the chain double-dashed line in FIG. 1, each light emitting unit 5 -1 ,
5 -2 , ... 5 -44 constant current diode 8 and resistor 9
In parallel with the series circuit of, the constant current diode 8 and the resistor 9
One series circuit or a plurality of series circuits may be connected in parallel. In this case, the resistor 9 can be shared.
【００１９】また、上述した実施例では、792 個の発光
ダイオードを組み込んでいるが、この個数に限定される
ものではない。また、本発明に係る表示装置は、航空障
害灯、工事現場における危険標識灯、交通信号機の表示
灯、あるいは文字表示機能とを組合わせた表示灯等の表
示装置全般に適用できることは勿論である。Further, in the above-mentioned embodiment, 792 light emitting diodes are incorporated, but the number is not limited to this. Further, it goes without saying that the display device according to the present invention can be applied to general display devices such as an aviation obstruction light, a danger sign light at a construction site, a traffic light indicator light, or an indicator light combined with a character display function. .
【００２０】[0020]
【発明の効果】以上説明したように、本発明によれば、
電源電圧の変動に左右されることなく、光源である発光
ダイオードに流れる電流を常に一定値に保持することが
できるので、表示装置としての信頼性向上に寄与できる
ばかりか、光源である発光ダイオードの長寿命化にも寄
与できる。As described above, according to the present invention,
Since the current flowing through the light emitting diode, which is the light source, can always be maintained at a constant value without being affected by the fluctuation of the power supply voltage, not only can the reliability of the display device be improved, but also that of the light emitting diode that is the light source. It can also contribute to longer life.
【図１】本発明の一実施例に係る表示装置の回路構成図FIG. 1 is a circuit configuration diagram of a display device according to an embodiment of the present invention.
１…全波整流電源回路 ２ａ，２ｂ…交
流入力端子 ４ａ，４ｂ…直流出力端子 ５-1，５-2，…
５-44 …発光ユニット ６…発光ダイオード ７…直列要素 ８…定電流素子としての定電流ダイオード ９…抵抗器1 ... Full wave rectification power supply circuit 2a, 2b ... AC input terminal 4a, 4b ... DC output terminal 5-1 , 5-2 , ...
5 -44 ... Light emitting unit 6 ... Light emitting diode 7 ... Series element 8 ... Constant current diode as constant current element 9 ... Resistor
───────────────────────────────────────────────────── フロントページの続き (72)発明者 小林 功 長野県長野市吉田３−８−29 中電吉田ア パートＥ−406 (72)発明者 松井 成仁 長野県松本市島内5293 中電島内変電所社 宅中電塩嶺寮312 (72)発明者 遠藤 正明 東京都品川区大崎４−３−８ 株式会社サ ンコーシヤ内 (72)発明者 原野 哲夫 東京都品川区大崎４−３−８ 株式会社サ ンコーシヤ内 (72)発明者 杉浦 之裕 東京都品川区大崎４−３−８ 株式会社サ ンコーシヤ内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isao Kobayashi 3-8-29 Yoshida Nagano City, Nagano Prefecture Nakaden Yoshida Apart E-406 (72) Inventor Naruhito Matsui 5293 Shimauchi, Matsumoto City, Nagano Substation Company Home Chuden Shiomine Dormitory 312 (72) Inventor Masaaki Endo 4-3-8 Osaki Shinagawa-ku, Tokyo Sankosha Co., Ltd. (72) Inventor Tetsuo Harano 4-3-8 Osaki Shinagawa-ku Tokyo Sankoshiya Co., Ltd. (72) Inventor Norihiro Sugiura 4-3-8 Osaki, Shinagawa-ku, Tokyo Sankosha Co., Ltd.
Claims (2)
素からなる光源を備えた表示装置において、前記直列要
素と直列に定電流素子が接続されてなることを特徴とす
る表示装置。1. A display device comprising a light source comprising a series element in which a plurality of light emitting diodes are connected in series, wherein a constant current element is connected in series with the series element.
ることを特徴とする請求項１に記載の表示装置。2. The display device according to claim 1, wherein the constant current element is a constant current diode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP629595A JPH08194448A (en) | 1995-01-19 | 1995-01-19 | Display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP629595A JPH08194448A (en) | 1995-01-19 | 1995-01-19 | Display device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08194448A true JPH08194448A (en) | 1996-07-30 |
Family
ID=11634391
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP629595A Pending JPH08194448A (en) | 1995-01-19 | 1995-01-19 | Display device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08194448A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006303165A (en) * | 2005-04-20 | 2006-11-02 | Epsel:Kk | Light emitting diode lighting device |
| US7408308B2 (en) | 2005-05-13 | 2008-08-05 | Sharp Kabushiki Kaisha | LED drive circuit, LED lighting device, and backlight |
| JP2010287459A (en) * | 2009-06-12 | 2010-12-24 | Suntec Inc | Led lighting module and lighting device using the same |
| WO2011052834A1 (en) * | 2009-10-26 | 2011-05-05 | (주)에어텍시스템 | Constant-current-drive led module device |
| US8044898B2 (en) | 2007-04-16 | 2011-10-25 | Nagano Keiki Co., Ltd. | LED display apparatus having a column and row controller |
-
1995
- 1995-01-19 JP JP629595A patent/JPH08194448A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006303165A (en) * | 2005-04-20 | 2006-11-02 | Epsel:Kk | Light emitting diode lighting device |
| US7408308B2 (en) | 2005-05-13 | 2008-08-05 | Sharp Kabushiki Kaisha | LED drive circuit, LED lighting device, and backlight |
| US8044898B2 (en) | 2007-04-16 | 2011-10-25 | Nagano Keiki Co., Ltd. | LED display apparatus having a column and row controller |
| JP2010287459A (en) * | 2009-06-12 | 2010-12-24 | Suntec Inc | Led lighting module and lighting device using the same |
| WO2011052834A1 (en) * | 2009-10-26 | 2011-05-05 | (주)에어텍시스템 | Constant-current-drive led module device |
| US8872434B2 (en) | 2009-10-26 | 2014-10-28 | Airtec System Co., Ltd. | Constant-current-drive LED module device |
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