JPH0555632A - Led array - Google Patents
Led arrayInfo
- Publication number
- JPH0555632A JPH0555632A JP23732491A JP23732491A JPH0555632A JP H0555632 A JPH0555632 A JP H0555632A JP 23732491 A JP23732491 A JP 23732491A JP 23732491 A JP23732491 A JP 23732491A JP H0555632 A JPH0555632 A JP H0555632A
- Authority
- JP
- Japan
- Prior art keywords
- light emitting
- electrode
- emitting body
- light
- electrodes
- 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.)
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Abstract
Description
【0001】[0001]
【発明の利用分野】この発明はLEDアレイの発光体と
電極構造とに関し、例えばLEDプリンタヘッドに用い
れば好適なものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting body and an electrode structure of an LED array, and is suitable for use in an LED printer head, for example.
【0002】[0002]
【従来技術】LEDアレイの電極構造としては、例えば
図4(実開平1−165,665号,特開平2−17
2,772号)、図5(実開平1−165,665号,
特開昭57−31,185号)に示すものが知られてい
る。図4の電極配置は発光体2の一端に電極4を設けた
もので、図5の電極配置は発光体2の中央を縦断するよ
うに電極6を設けたものである。なお各図でハッチング
を加えた部分8,9は、電極4,6で発光体2を被覆し
た遮蔽部である。2. Description of the Related Art As an electrode structure of an LED array, for example, a structure shown in FIG.
2,772), FIG. 5 (actual Kaihei 1-165,665,
Those disclosed in JP-A-57-31,185) are known. In the electrode arrangement shown in FIG. 4, the electrode 4 is provided at one end of the light emitting body 2, and in the electrode arrangement shown in FIG. 5, the electrode 6 is provided so as to vertically cut the center of the light emitting body 2. The hatched portions 8 and 9 in the respective drawings are shielding portions in which the light emitting body 2 is covered with the electrodes 4 and 6.
【0003】図4の電極配置では、電極4が図の上下に
シフトすると、電極4による遮蔽部8の面積が変化し、
発光出力が変動する。また発光体2の輝度分布は図4の
右側の特性となり、電極4側と反対側とで輝度が異な
り、発光体2の全面を均一に発光させられないため発光
出力も低下する。In the electrode arrangement of FIG. 4, when the electrode 4 shifts up and down in the figure, the area of the shielding portion 8 by the electrode 4 changes,
The light output changes. Further, the luminance distribution of the light emitting body 2 has the characteristic on the right side of FIG. 4, the luminance is different between the electrode 4 side and the opposite side, and since the entire surface of the light emitting body 2 cannot be emitted uniformly, the light emission output is also reduced.
【0004】図5の電極配置では、図の上下への電極6
のシフトでは出力に影響は生じないが、図の左右に電極
6がシフトすると出力が変動する。更に図の鎖線で示し
たように、電極6の幅が変動すると発光出力が変動す
る。In the electrode arrangement shown in FIG. 5, the electrodes 6 are placed on the upper and lower sides of the figure.
The shift does not affect the output, but the output fluctuates when the electrode 6 shifts left and right in the figure. Further, as indicated by the chain line in the figure, when the width of the electrode 6 changes, the light emission output also changes.
【0005】このような電極の位置のむらや幅のむらが
生じる原因について検討する。電極は通常、基板の全面
に形成した後エッチングにより製造する。あるいは最初
にレジストによるマスクを形成した後、全面に電極を形
成し、リフトオフにより所望の形状とする。ここで電極
のマスクと基板との、マスク合わせ精度が有る。またL
EDアレイに主として用いられるGaAs系の基板は、
反りが±100μm程度と大きく、マスク合わせだけで
は解決できない斜め露光等の問題が有る。更に多数の発
光体を集積したLEDアレイでは、発光体2自体の位置
もアレイの左右でばらつきが有る。これらの他にエッチ
ング条件の変動がある。例えば僅かなエッチング液の濃
度変動や温度変動、エッチング時間の変動等により、エ
ッチング不足が生じ、あるいは逆にエッチング過剰が生
じる。結局これらのために、電極の発光体に対する位置
精度は±5μm程度が限界となる。LEDアレイの数十
μm角程度の発光体に対し±5μm程度の電極のずれ
は、±10%程度の発光出力の変動をもたらし、例えば
プリンタヘッドに用いる場合の印画品質を低下させる。The cause of such uneven position and uneven width of the electrodes will be examined. The electrodes are usually manufactured by etching after forming on the entire surface of the substrate. Alternatively, a resist mask is first formed, electrodes are formed on the entire surface, and a desired shape is obtained by lift-off. Here, there is mask alignment accuracy between the electrode mask and the substrate. Also L
The GaAs type substrate mainly used for the ED array is
The warpage is as large as about ± 100 μm, and there are problems such as oblique exposure that cannot be solved only by mask alignment. In an LED array in which a large number of light emitters are integrated, the position of the light emitter 2 itself also varies from side to side in the array. In addition to these, there are variations in etching conditions. For example, due to slight fluctuations in the concentration of the etching solution, fluctuations in temperature, fluctuations in etching time, and the like, insufficient etching occurs, or conversely, excessive etching occurs. After all, for these reasons, the positional accuracy of the electrode with respect to the light emitter is limited to about ± 5 μm. The deviation of the electrodes of about ± 5 μm with respect to the light emitting body of the LED array having a size of several tens of μm square causes a variation of the light emission output of about ± 10%, and deteriorates the printing quality when used for a printer head, for example.
【0006】[0006]
【発明の課題】この発明の課題は、LEDアレイの電極
形状の最適化に有り、電極位置の変動に対する許容幅が
大きく、発光体内部の輝度分布が均一で、電極による発
光体の遮蔽面積が小さい、電極形状を提供することに有
る。SUMMARY OF THE INVENTION An object of the present invention is to optimize the electrode shape of an LED array, which has a large tolerance for fluctuations in electrode position, has a uniform luminance distribution inside the light emitter, and has a shielded area of the light emitter by the electrode. It is to provide a small electrode shape.
【0007】[0007]
【発明の構成】この発明は、半導体基板上に多数の発光
体を形成し、各発光体に電極を接続したLEDアレイに
おいて、該発光体は少なくともその両端に突き出し部を
部分的に設け、電極は該突き出し部を部分的に被覆する
と共に、突き出し部以外の部分では、電極と発光体との
間に所定幅のクリアランスを設けたことを特徴とする、
LEDアレイに有る。According to the present invention, in an LED array in which a large number of light-emitting bodies are formed on a semiconductor substrate and electrodes are connected to the respective light-emitting bodies, the light-emitting bodies are provided with protruding portions at least at both ends thereof, Is characterized in that the protruding portion is partially covered, and a clearance having a predetermined width is provided between the electrode and the light emitting body in a portion other than the protruding portion.
It is in the LED array.
【0008】[0008]
【発明の作用】この発明では、発光体の突き出し部以外
の部分では、電極と発光体との間にクリアランスを設け
る。ここでクリアランスを電極の発光体に対する位置精
度(以下単に電極の位置精度という)以上の幅とすれ
ば、電極位置が変動しても発光体には影響しない。また
突き出し部は発光体の両端に設け、両端から発光電流を
流し込むので、発光体の内部での輝度分布はほぼ均一と
なる。そして突き出し部は発光体に比べ小さいので、電
極による遮蔽面積は小さく、かつ突き出し部での電極位
置が変動しても、小さな突き出し部での遮蔽面積が変動
するだけで発光出力への影響は小さい。According to the present invention, a clearance is provided between the electrode and the light emitting body at a portion other than the protruding portion of the light emitting body. If the clearance has a width greater than the positional accuracy of the electrode with respect to the light emitter (hereinafter simply referred to as electrode position accuracy), the light emitter is not affected even if the electrode position changes. Further, since the protruding portions are provided at both ends of the light emitting body and a light emitting current is supplied from both ends, the luminance distribution inside the light emitting body becomes substantially uniform. Since the protruding portion is smaller than the light emitting body, the shielding area by the electrode is small, and even if the electrode position at the protruding portion changes, the shielding area at the small protruding portion only changes and the influence on the light emission output is small. ..
【0009】[0009]
【実施例】図1に実施例を示し、図2にその変形例を示
し、図3に実施例の輝度分布を示す。図1において、1
0はGaAs基板で、12は発光体である。発光体12
は例えば300DPIの密度で配置し、1アレイに64
個集積する。この結果、発光体12の幅Wは45μm、
長さLは60μm、発光体12のピッチは84.6μm
となる。14は発光体12の突き出し部で、発光体12
の長手方向の両端に設けたが、ピッチが許す場合左右の
両端に設けても良い。16,18は電極で、発光体12
の突き出し部14とオーミック接続し、電極16,18
から上下両端の突き出し部14に発光電流を流し込み、
発光体12を発光させる。電極16,18の材質には、
例えばAlを用いる。なお電極16を電極18と左右反
転にしたのは、LEDアレイの端の電極だからである。
20は、電極16,18による突き出し部14の遮蔽部
である。遮蔽部20には右下向きのハッチングを施し
た。また22は電極16,18と発光体12の間のクリ
アランスで、電極16,18の形状精度±5μmに応
じ、5μm以上の幅とする。24は、GaAs基板10
の発光体12以外の部分を被覆した、SiNx等の保護
膜である。EXAMPLE FIG. 1 shows an example, FIG. 2 shows a modification thereof, and FIG. 3 shows the luminance distribution of the example. In FIG. 1, 1
Reference numeral 0 is a GaAs substrate, and 12 is a light emitter. Luminous body 12
Are arranged at a density of, for example, 300 DPI, and 64 are arranged in one array.
Collect individually. As a result, the width W of the light emitting body 12 is 45 μm,
The length L is 60 μm, and the pitch of the light emitters 12 is 84.6 μm.
Becomes Reference numeral 14 denotes a protruding portion of the light emitting body 12,
Although they are provided at both ends in the longitudinal direction, they may be provided at both left and right ends if the pitch allows. Reference numerals 16 and 18 denote electrodes, which are light-emitting members
Ohmic connection to the protruding portion 14 of the
Light emission current is flown into the protruding portions 14 at the upper and lower ends,
The light emitting body 12 is caused to emit light. The materials of the electrodes 16 and 18 are
For example, Al is used. The electrode 16 is laterally inverted with respect to the electrode 18 because it is an electrode at the end of the LED array.
Reference numeral 20 is a shielding portion of the protruding portion 14 by the electrodes 16 and 18. The shielding portion 20 is hatched in the lower right direction. Reference numeral 22 denotes a clearance between the electrodes 16 and 18 and the light emitting body 12, which has a width of 5 μm or more depending on the shape accuracy of the electrodes 16 and 18 of ± 5 μm. 24 is a GaAs substrate 10
Is a protective film made of SiNx or the like, which covers portions other than the light emitting body 12.
【0010】電極16,18の発光体12への位置精度
は、基板10の±100μm程度の反り、発光体12自
体の±5μm程度の位置精度、電極形成時のマスクの精
度、エッチング速度のむらやサイドエッチの有無等によ
り、±5μm程度が限界となる。そこで各部の形状をこ
の精度に準じて定めた。先ず突き出し部14は、図の上
下の奥行きを15μmとし、このうち露出部の奥行きA
を5μm、遮蔽部20の奥行きCを10μmとし、±5
μmの変動で発光体12の本体(45×60μmの部
分)を遮蔽せず、少なくとも5μmの遮蔽部が残るよう
にした。突き出し部14の幅Dは45μmよりも小さい
範囲で任意であるが、発光体12を均一に発光させ得る
値として、実験結果に基づき15μmとした。幅Dの好
ましい範囲は、幅Wの1/4〜1/2である。電極1
6,18は、発光体12の長手方向に平行な最も幅の狭
い部分で8μm幅とし、電極16,18が平行に並ぶ部
分で、3つの隙間に対し各8μm弱を割り当てた。クリ
アランス22の、発光体12の長手方向に平行な部分で
の幅Bは8μmである。The positional accuracy of the electrodes 16 and 18 with respect to the light emitting body 12 is such that the substrate 10 has a warp of about ± 100 μm, the positional accuracy of the light emitting body 12 itself is about ± 5 μm, the accuracy of the mask during electrode formation, and the uneven etching rate. The limit is about ± 5 μm depending on the presence or absence of side etching. Therefore, the shape of each part was determined according to this accuracy. First, the protruding portion 14 has a vertical depth of 15 μm in the figure, of which the depth A of the exposed portion is
Is 5 μm and the depth C of the shielding portion 20 is 10 μm, and ± 5
The main body of the light emitting body 12 (45 × 60 μm portion) was not shielded by the fluctuation of μm, and at least a shield portion of 5 μm was left. The width D of the protruding portion 14 is arbitrary within a range smaller than 45 μm, and is set to 15 μm based on the experimental result as a value capable of causing the light emitting body 12 to uniformly emit light. The preferable range of the width D is 1/4 to 1/2 of the width W. Electrode 1
Numerals 6 and 18 have a width of 8 μm at the narrowest portion parallel to the longitudinal direction of the light emitting body 12, and portions where the electrodes 16 and 18 are arranged in parallel are assigned a little less than 8 μm to each of the three gaps. The width B of the clearance 22 in the portion parallel to the longitudinal direction of the light emitting body 12 is 8 μm.
【0011】図2の変形例では、発光体32の上下に突
き出し部14を設け、左右に突き出し部34を設けた。
38は発光体32の4周を囲む電極、40は左右の突き
出し部34の遮蔽部、42はクリアランスである。In the modification of FIG. 2, the protrusions 14 are provided on the upper and lower sides of the light emitting body 32, and the protrusions 34 are provided on the left and right sides.
Reference numeral 38 is an electrode that surrounds the light-emitting body 32 around the four circumferences, 40 is a shielding portion for the left and right protrusions 34, and 42 is a clearance.
【0012】図1の実施例の特性を説明する。電極1
6,18は、クリアランス22の幅Bを8μm、幅Aを
5μmとしたので、電極位置が±5μm変動しても、発
光体12の本体(45×60μmの部分)には接触しな
い。突き出し部14の部分では、電極が±5μm変動し
ても発光体12の本体を遮蔽せず、また遮蔽部20は少
なくとも5μmの奥行きが残る。また発光特性は図3に
示すように、(図3には発光体12の中心に沿った輝度
分布を示す)、発光体12の上下両端から発光電流を注
入するため、図の実線のように突き出し部14を除き、
ほぼ均一な輝度分布が得られる。なお図の破線は各遮蔽
部からの発光電流を示す。遮蔽部20の面積は小さく、
突き出し部14の幅が狭いため電極位置が変動しても遮
蔽面積の変動は小さい。The characteristics of the embodiment shown in FIG. 1 will be described. Electrode 1
In Nos. 6 and 18, the width B of the clearance 22 is 8 μm and the width A is 5 μm. Therefore, even if the electrode position fluctuates by ± 5 μm, it does not contact the main body of the light-emitting body 12 (45 × 60 μm portion). In the protruding portion 14, even if the electrode fluctuates ± 5 μm, the main body of the light emitting body 12 is not shielded, and the shielding portion 20 has a depth of at least 5 μm. As for the light emission characteristics, as shown in FIG. 3 (the luminance distribution along the center of the light emitting body 12 is shown in FIG. 3), since the light emitting current is injected from the upper and lower ends of the light emitting body 12, as shown by the solid line in the figure. Excluding the protruding portion 14,
An almost uniform brightness distribution can be obtained. The broken line in the figure indicates the light emission current from each shield. The area of the shielding portion 20 is small,
Since the width of the protruding portion 14 is narrow, the variation of the shielding area is small even if the electrode position varies.
【0013】図4,図5の従来例と、図1の実施例につ
いて、電極による遮蔽面積とその変動とについて、比較
する。なお発光体はいずれも45μm×60μmとす
る。図4の従来例で遮蔽部8の幅は、±5μmの電極精
度を考慮すると10μmが必要である。また図5の従来
例では、エッチングの過不足による電極6の左右のシフ
トが±2.5μmとすると、10μm幅の電極が必要と
なる。これらを基に、発光体の総面積、電極による標準
遮蔽面積、電極位置の上下左右への±5μmのアライン
メント誤差による遮蔽面積の変化、±2.5μmのエッ
チングの過不足による遮蔽面積の変化を、表1に示す。The shielding area by the electrode and its variation will be compared between the conventional example shown in FIGS. 4 and 5 and the embodiment shown in FIG. The size of each light-emitting body is 45 μm × 60 μm. In the conventional example of FIG. 4, the width of the shielding portion 8 needs to be 10 μm in consideration of the electrode accuracy of ± 5 μm. Further, in the conventional example of FIG. 5, if the lateral shift of the electrode 6 due to excess or deficiency of etching is ± 2.5 μm, an electrode having a width of 10 μm is required. Based on these, the total area of the light emitter, the standard shielding area by the electrode, the variation of the shielding area due to the alignment error of ± 5 μm up and down and left and right of the electrode position, and the variation of the shielding area due to the excess or deficiency of etching of ± 2.5 μm , Shown in Table 1.
【0014】[0014]
【表1】 [Table 1]
【0015】表1から明らかなように実施例では、電極
による遮蔽面積が小さく発光体12を有効に発光させる
ことができ、電極16,18のマスク合わせ時のアライ
ンメント誤差では遮蔽面積が変動せず、更にエッチング
の過不足に対する遮蔽面積の変動も少ない。遮蔽面積の
変動はエッチングの過不足によるものだけで、その値は
総発光面積の2.5%程度に過ぎず、図4,図5の従来
例の1/4以下となる。更に図5の従来例では、電極6
が左右にずれると輝度が不均一となるが、実施例では電
極16,18の左右のずれは遮蔽部20に影響しない。
これらのため、実施例のLEDアレイをプリンタヘッド
に用いると、各発光体12の内部での輝度が均一で、電
極の精度による発光出力の変動が小さいため、高品質の
印画賀できる。As is clear from Table 1, in the embodiment, the shielding area by the electrodes is small and the light emitting body 12 can effectively emit light, and the shielding area does not change due to the alignment error at the time of mask alignment of the electrodes 16 and 18. Moreover, the variation of the shielded area with respect to the excess or deficiency of etching is small. The variation of the shielded area is only due to the excess or deficiency of etching, and its value is only about 2.5% of the total light emitting area, which is 1/4 or less of the conventional example of FIGS. 4 and 5. Furthermore, in the conventional example of FIG.
However, in the embodiment, the horizontal displacement of the electrodes 16 and 18 does not affect the shielding portion 20.
For these reasons, when the LED array of the embodiment is used for a printer head, the luminance inside each light emitting body 12 is uniform, and the fluctuation of the light emission output due to the accuracy of the electrodes is small, so that high quality printing can be performed.
【0016】[0016]
【発明の効果】この発明では、電極位置の変動やエッチ
ングの過不足による電極幅の影響を抑え発光体を均一に
発光させると共に、発光体の内部での輝度分布を小さく
し、高品位のLEDアレイが得られる。According to the present invention, it is possible to suppress the influence of the electrode width due to the fluctuation of the electrode position and the excess or deficiency of etching, and to make the light emitting body emit light uniformly, and to reduce the luminance distribution inside the light emitting body, thereby providing a high quality LED. An array is obtained.
【図1】 実施例のLEDアレイの要部平面図FIG. 1 is a plan view of a main part of an LED array according to an embodiment.
【図2】 変形例のLEDアレイの要部平面図FIG. 2 is a plan view of a main part of a modified LED array.
【図3】 実施例のLEDアレイの輝度分布を示す特性
図FIG. 3 is a characteristic diagram showing the luminance distribution of the LED array of the example.
【図4】 従来例のLEDアレイの要部平面図FIG. 4 is a plan view of a main part of a conventional LED array.
【図5】 従来例のLEDアレイの要部平面図FIG. 5 is a plan view of a main part of a conventional LED array.
10 GaAs基板 12 発光体 14 突き出し部 16 電極 18 電極 20 遮蔽部 22 クリアランス 24 保護膜 10 GaAs Substrate 12 Light-Emitting Body 14 Projection 16 Electrode 18 Electrode 20 Shield 22 Clearance 24 Protective Film
Claims (1)
各発光体に電極を接続したLEDアレイにおいて、 該発光体は少なくともその両端に突き出し部を部分的に
設け、電極は該突き出し部を部分的に被覆すると共に、
突き出し部以外の部分では、電極と発光体との間に所定
幅のクリアランスを設けたことを特徴とする、LEDア
レイ。1. A large number of light emitters are formed on a semiconductor substrate,
In an LED array in which an electrode is connected to each light-emitting body, the light-emitting body is partially provided with protruding portions at both ends thereof, and the electrodes partially cover the protruding portions, and
An LED array, characterized in that a clearance having a predetermined width is provided between the electrode and the light-emitting body in a portion other than the protruding portion.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP23732491A JPH0555632A (en) | 1991-08-22 | 1991-08-22 | Led array |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP23732491A JPH0555632A (en) | 1991-08-22 | 1991-08-22 | Led array |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0555632A true JPH0555632A (en) | 1993-03-05 |
Family
ID=17013688
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP23732491A Pending JPH0555632A (en) | 1991-08-22 | 1991-08-22 | Led array |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0555632A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7452103B2 (en) | 2004-04-05 | 2008-11-18 | Hoya Corporation | Illuminating device for photoshooting |
-
1991
- 1991-08-22 JP JP23732491A patent/JPH0555632A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7452103B2 (en) | 2004-04-05 | 2008-11-18 | Hoya Corporation | Illuminating device for photoshooting |
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