JP2527572B2 - Light emitting diode array for optical printer - Google Patents
Light emitting diode array for optical printerInfo
- Publication number
- JP2527572B2 JP2527572B2 JP25400087A JP25400087A JP2527572B2 JP 2527572 B2 JP2527572 B2 JP 2527572B2 JP 25400087 A JP25400087 A JP 25400087A JP 25400087 A JP25400087 A JP 25400087A JP 2527572 B2 JP2527572 B2 JP 2527572B2
- Authority
- JP
- Japan
- Prior art keywords
- light emitting
- light
- diode array
- emitting diode
- optical printer
- 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.)
- Expired - Lifetime
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/435—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of radiation to a printing material or impression-transfer material
- B41J2/447—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of radiation to a printing material or impression-transfer material using arrays of radiation sources
- B41J2/45—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of radiation to a printing material or impression-transfer material using arrays of radiation sources using light-emitting diode [LED] or laser arrays
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Dot-Matrix Printers And Others (AREA)
- Exposure Or Original Feeding In Electrophotography (AREA)
- Led Devices (AREA)
Description
【発明の詳細な説明】 イ）産業上の利用分野 本発明は高品位な印写が行なえるモノリシツク形の光
プリンタ用発光ダイオードアレイに関する。DETAILED DESCRIPTION OF THE INVENTION a) Field of Industrial Application The present invention relates to a monolithic light emitting diode array for an optical printer capable of high-quality printing.
ロ）従来の技術 近年例えば特開昭61−237484号公報等に示される様に
モノリシツク形の発光ダイオードアレイを用いて光プリ
ンタへツドを構成している。この様な光プリンタヘツド
においては感光面に投影されるドツトの形が発光領域と
１対１に対応するため、第２図に示すような発光部（1
2）（12）…の輝度均一化はもとより、１発光部（12）
における形状をドツト形状に整えること、および１発光
部（12）内の輝度分布を整えることが印写品位を向上さ
せるために必要である。(B) Prior Art In recent years, an optical printer head is constructed using a monolithic light emitting diode array as disclosed in, for example, Japanese Patent Laid-Open No. 61-237484. In such an optical printer head, the shape of the dots projected on the photosensitive surface has a one-to-one correspondence with the light emitting area, so that the light emitting portion (1
2) (12) ..., as well as uniform brightness, 1 light emitting part (12)
In order to improve the printing quality, it is necessary to adjust the shape in (1) to a dot shape and to adjust the luminance distribution in the first light emitting portion (12).
ハ）発明が解決しようとする問題点 この様に発光部の１つ１つに着目すると印写品位とド
ツトとの関係がより重要になる。印写品位を向上させる
ドツトの条件として、ドツトの輪郭が明瞭であることが
あげられ、さらにより好ましくは、例えば隣接するドツ
トを印写した時ドツト間の他の色（概ね白色）が目立た
ない程度にドツトの大きさが充分大きいことがあげられ
る。C) Problems to be solved by the invention As described above, focusing on each of the light emitting parts, the relationship between the print quality and the dot becomes more important. The condition of the dot that improves the printing quality is that the outline of the dot is clear. Even more preferably, for example, when the adjacent dots are printed, other colors (generally white) between the dots are not noticeable. The size of the dots is sufficiently large.
ドツトの輪郭は発光部の端縁の輝度が高くなると明瞭
になることがわかったが、その端縁の輝度を向上させる
為に電流を大きくすると発光部全体の電流量も増大し、
発熱量が増え素子の劣化を早めるので好ましくない。一
方、光取出量を増大するために発光部に被膜を設ければ
よいことは実開昭58−159763号公報に示されているが、
被膜によってはむしろ発光部の光取出量が減少すること
すらあることがわかった。It was found that the contour of the dot became clear when the brightness of the edge of the light emitting part increased, but if the current was increased to improve the brightness of the edge, the current amount of the entire light emitting part also increased,
This is not preferable because the amount of heat generated increases and the deterioration of the element is accelerated. On the other hand, it is disclosed in Japanese Utility Model Application Laid-Open No. 58-159763 that the light emitting portion may be provided with a coating in order to increase the light extraction amount.
It was found that, depending on the coating, the light extraction amount of the light emitting part may be reduced.
本発明は上述の点を考慮して、ドツトの輪郭が明瞭
で、しかもドツト密度に対して充分大きいドツトを印写
することのできる光プリンタ用発光ダイオードアレイを
提供するものである。In view of the above points, the present invention provides a light emitting diode array for an optical printer capable of printing dots having clear dot contours and sufficiently large dot density.
ニ）問題点を解決するための手段 本発明は、先に上述した被覆の色程と光取出量との間
に相関がある事を見出した（特願昭62−36172号）で
の、さらに被膜の光拡散性を組合せることに着目してな
されたもので、発光部の整列側端縁近傍を覆う被膜とし
て補色を呈し、かつ厚みが光伝播を生じる厚み、より好
ましくは200nm以上の厚みのものを用いるものである。D) Means for Solving the Problems In the present invention, it was found that there is a correlation between the color range of the coating and the light extraction amount described above (Japanese Patent Application No. 62-36172). It was made by paying attention to the combination of the light diffusivity of the coating, and it has a complementary color as a coating covering the vicinity of the alignment side edge of the light emitting part, and the thickness that causes light propagation, more preferably a thickness of 200 nm or more. The one used is.
ホ）作用 これにより発光部近傍の輝度分布が略Ｍ字状となって
端縁が高輝度化し、これによりドツトの輪郭が明瞭とな
り、隣接発光部の点灯で絶縁被膜は光拡散・光溜効果を
生じ、ドツトは大きく投影される。(E) Action As a result, the luminance distribution near the light emitting portion becomes approximately M-shaped and the edge becomes brighter, and the contour of the dot becomes clear, and the insulating coating has a light diffusion and light accumulating effect when the adjacent light emitting portion is lit. It occurs and the dots are projected large.
ヘ）実施例 第１図は本発明実施例の光プリンタ用発光ダイオード
アレイの要部断面図（ａ）と特性図（ｂ）（ｃ）であ
る。図において（１）はGaAsP等の化合物半導体の基板
で、その表面には選択拡散により発光部（２）（２）…
が１列に整列して設けられ、その各々にはオーミツク接
触された電極（第２図（13）参照）が設けられている。
（４）は発光部（２）（２）…を形成するに際し拡散マ
スクとして用いた絶縁膜で（５）は露出した発光部
（２）（２）…表面及び基板や電極表面をも覆う被膜で
ある。この被膜（５）は少なくとも発光部（２）（２）
…の整列方向（図の水平方向）に位置する端縁（Ａ）近
傍を覆っているが、以後の説明では発光部の端縁部分の
絶縁被膜（端縁被膜と略称）として、絶縁膜（４）が遮
光性等光学特性をもたないときは端縁（Ａ）近傍の被膜
（５）を示し、絶縁膜（４）が被膜（５）と同じ材料等
により同等の光学特性を有する場合は絶縁膜（４）と被
膜（５）の積層体を示す。F) Embodiment FIG. 1 is a sectional view (a) and characteristic views (b) and (c) of a main part of a light emitting diode array for an optical printer according to an embodiment of the present invention. In the figure, (1) is a substrate of a compound semiconductor such as GaAsP, and light emitting parts (2) (2) ...
Are arranged in a line and each of them is provided with an electrode (see FIG. 2 (13)) in ohmic contact.
Reference numeral (4) is an insulating film used as a diffusion mask when forming the light emitting portions (2), (2) ... And (5) is a film which covers the exposed light emitting portions (2), (2). Is. This coating (5) is at least the light emitting part (2) (2)
Although it covers the vicinity of the edge (A) located in the alignment direction of (...) (Horizontal direction in the figure), in the following description, an insulating film (abbreviated as edge film) is used as an insulating film (abbreviated as edge film) of the edge portion of the light emitting portion. When 4) does not have optical characteristics such as light-shielding property, it shows the coating (5) near the edge (A), and the insulating film (4) has the same optical characteristics by the same material as the coating (5). Indicates a laminate of the insulating film (4) and the coating film (5).
この様な絶縁被膜において、第１図に例示した発光ダ
イオードアレイは以下の様に構成されている。尚、第１
図（Ｃ）において点線は被膜のない輝度分布特性、実線
は本発明実施例に係る輝度分布特性である。In such an insulating film, the light emitting diode array illustrated in FIG. 1 is configured as follows. The first
In FIG. 6C, the dotted line shows the luminance distribution characteristic without the coating, and the solid line shows the luminance distribution characteristic according to the embodiment of the present invention.
この様に端縁被膜を発光色と略補色にする事で発光部
端縁の光取出量を増加させ、輝度分布が略Ｍ字状をなす
ようにし、もってドツトの輪郭を明瞭とすることができ
る。電極が発光部の略中央に細帯状に存在していても発
光部端縁での光取出量を輪郭明瞭化のために大きくする
ことが出来る。 In this way, by making the edge coating almost complementary to the emission color, the amount of light extracted at the edge of the light emitting portion is increased so that the brightness distribution is substantially M-shaped, and thus the outline of the dots can be made clear. it can. Even if the electrode is present in the shape of a strip in the approximate center of the light emitting portion, the light extraction amount at the edge of the light emitting portion can be increased for clarifying the contour.
より詳細な例としてCVD法による端縁被膜の色呈と光
学特性を以下に示す。As a more detailed example, the coloration and optical characteristics of the edge coating by the CVD method are shown below.
これらの表において、ドツト間とあるのは、単独ドツ
ト印写でにじみがなく隣接ドツト印写でドツトが連接す
るもの◎、隣接ドツト印写でドツト間の他の色が目立た
ないもの○、全面印写でドツト間に白線が見えるもの
×、他のもの△として表示してある。 In these tables, the space between dots means that the dots are connected with each other without any bleeding with a single dot print ◎, other colors between dots are not conspicuous with the adjacent dot print ○, full surface A white line is visible between the dots in the print, and the other is marked as Δ.
これらの表から明らかな如く端縁被膜の色呈は膜厚に
応じて周期的に変化し、例えばGaAsP/GaAs赤色（λ＝66
0nm）発光ダイオードアレイにおいて、色呈が発光色に
対して補色である青緑を中心に、目視でほぼ青緑と観察
される緑〜青のあたり（第１図（ｂ）で青・緑の表示の
ある部分より上方）において輝度が25〜40％上昇する。
そして被膜の厚さが波長の約1/6を越えると被膜は光伝
播特性（いわゆる光パイプ効果）を示すが、さらに上述
の略補色を呈している状態では光伝播による光拡散効果
に加えていわゆる光溜め効果も加わり、ドツト間におい
て光放出量の増大・均一化の現象がみられる。従ってこ
の様子を短焦点レンズアレイで感光面に投影すると、第
１図において説明した様に、ドツトの輪郭が明瞭で、し
かも隣接ドツト印写においてのドツトが大きい。As is clear from these tables, the coloration of the edge coating changes periodically according to the film thickness, for example, GaAsP / GaAs red (λ = 66
(0 nm) In the light emitting diode array, the green color is centered around blue-green which is a complementary color to the emission color, and green to blue, which is visually observed to be almost blue-green (see FIG. 1 (b)). The brightness is increased by 25 to 40% above the display part).
When the thickness of the coating exceeds about 1/6 of the wavelength, the coating exhibits light propagation characteristics (so-called light pipe effect). In addition, in the state of exhibiting the above-mentioned substantially complementary color, in addition to the light diffusion effect by light propagation, A so-called light accumulation effect is also added, and the phenomenon that the amount of light emission is increased and made uniform between dots is observed. Therefore, when this state is projected onto the photosensitive surface by the short focus lens array, the contour of the dot is clear and the dot in the adjacent dot printing is large, as described in FIG.
尚第１図の例において、発光ダイオードアレイの端に
位置する発光部は切断歪等で輝度減少を生じやすいの
で、これを補う為に補色を呈する被膜を設けている。In the example shown in FIG. 1, the light emitting portion located at the end of the light emitting diode array is apt to cause a decrease in luminance due to cutting distortion or the like, and therefore a coating film having a complementary color is provided to compensate for this.
ト）発明の効果 以上の如くにより、発光部の端縁の光取出量を向上さ
せ、さらにそれに用いた絶縁被膜で隣接ドツト印写のド
ツトを大きくするので、駆動電流を特別に大きくするこ
となく高い印写品位を得ることができる。また、被膜が
発光部の端縁部分で発光色に対し補色を呈するので、被
膜の状態判別を目視によって簡単に行うことができる。G) Effect of the invention As described above, the light extraction amount at the edge of the light emitting portion is improved, and the dot of the adjacent dot printing is increased by the insulating film used therefor, so that the drive current is not particularly increased. High print quality can be obtained. Further, since the coating film has a color complementary to the emission color at the edge portion of the light emitting portion, the state of the coating film can be easily determined visually.
第１図は本発明実施例の光プリンタ用発光ダイオードア
レイの要部断面図（ａ）と特性図（ｂ）（ｃ）、第２図
は発光ダイオードアレイの斜視図である。 （１）…基板、（２）（２）…発光部、（４）…絶縁
膜、（５）…被膜。FIG. 1 is a sectional view (a) and characteristic diagrams (b) and (c) of a light emitting diode array for an optical printer according to an embodiment of the present invention, and FIG. 2 is a perspective view of the light emitting diode array. (1) ... Substrate, (2) (2) ... Light emitting part, (4) ... Insulating film, (5) ... Coating.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭62−196877（ＪＰ，Ａ) 特開 昭60−83384（ＪＰ，Ａ) 特開 昭63−58379（ＪＰ，Ａ) 特開 昭63−203350（ＪＰ，Ａ) 特開 昭63−66979（ＪＰ，Ａ) 特開 昭63−65685（ＪＰ，Ａ) 特開 昭63−9270（ＪＰ，Ａ) 特開 昭62−55973（ＪＰ，Ａ) ─────────────────────────────────────────────────── --- Continued from the front page (56) Reference JP 62-196877 (JP, A) JP 60-83384 (JP, A) JP 63-58379 (JP, A) JP 63- 203350 (JP, A) JP 63-66979 (JP, A) JP 63-65685 (JP, A) JP 63-9270 (JP, A) JP 62-55973 (JP, A)
Claims (2)
して設けられた複数の発光部と、発光部にオーミツク接
触された電極と、少なくとも発光部の整列方向に位置す
る端縁近傍を覆い、その端縁部分で発光色に対し補色を
呈しかつ光伝播を生ずる厚みを有する透光性の絶縁被膜
を具備した事を特徴とする光プリンタ用発光ダイオード
アレイ。1. A compound semiconductor substrate, a plurality of light emitting portions arranged in alignment on the surface of the substrate, an electrode in ohmic contact with the light emitting portion, and at least an edge portion located in the alignment direction of the light emitting portions. A light-emitting diode array for an optical printer, which is provided with a light-transmissive insulating film which covers and has a thickness complementary to the emission color at its edge portion and causing light propagation.
みは200nm以上である事を特徴とする特許請求の範囲第
１項記載の光プリンタ用発光ダイオードアレイ。2. The light emitting diode array for an optical printer according to claim 1, wherein the thickness of the insulating coating on the edge portion of the light emitting portion is 200 nm or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25400087A JP2527572B2 (en) | 1987-10-08 | 1987-10-08 | Light emitting diode array for optical printer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25400087A JP2527572B2 (en) | 1987-10-08 | 1987-10-08 | Light emitting diode array for optical printer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0195072A JPH0195072A (en) | 1989-04-13 |
| JP2527572B2 true JP2527572B2 (en) | 1996-08-28 |
Family
ID=17258870
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25400087A Expired - Lifetime JP2527572B2 (en) | 1987-10-08 | 1987-10-08 | Light emitting diode array for optical printer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2527572B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5115286A (en) * | 1988-08-26 | 1992-05-19 | Hewlett-Packard Company | Electro-optical device with inverted transparent substrate and method for making same |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6083384A (en) * | 1983-10-14 | 1985-05-11 | Ricoh Co Ltd | Led array light source |
| JPS62196877A (en) * | 1986-02-22 | 1987-08-31 | Rohm Co Ltd | Method for compensating luminance of light emitting element |
| JPS6358379A (en) * | 1986-08-29 | 1988-03-14 | Hitachi Ltd | Time-division driven liquid crystal optical switch array for printer |
-
1987
- 1987-10-08 JP JP25400087A patent/JP2527572B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0195072A (en) | 1989-04-13 |
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