JP3798874B2 - Multi-beam recording device - Google Patents

Description

【００２１】
描画幅の変更には、高い描画精度が要求される場合に、投影レンズの外側の収差の影響が大きい領域を利用する光を利用せず投影レンズの中心部を通る光のみを利用するという第１の目的と、いずれかのＬＥＤが断線等の原因により発光不能となったときに、そのＬＥＤを含むグループを使用せずに描画することによりドットの抜けを防止するという第２の目的とがある。第１の目的を達成するためには、幅方向の外側の領域に対応するＬＥＤを使用せず、中央の領域に対応するＬＥＤのみを利用して描画する必要がある。この場合には、ＡとＦとの２通りの組み合わせが選択できれば十分である。ただし、第２の目的を達成するためには、他のＢ〜Ｅ，Ｇ〜Ｊの組み合わせも選択できることが望ましい。
【００２２】
標準密度で描画する場合、感光フィルム３の描画領域のＹ方向における端部から他の端部まで帯状に画像が形成されると、光学ヘッド４を上記の使用されるグループの数に応じた描画幅分だけＸ方向に移動する。そして、光学ヘッド４の移動後にテーブル２を前回とは逆方向に（Ｙ方向に沿って）移動することにより、同様にして、感光フィルム３にＹ方向に延びた帯状の画像を先に形成した領域に隣接して形成する。標準密度の場合、光学へッドはテーブルがいずれの方向に走査する場合にも走査が終了する毎に１０．２４−（ｍ＋ｎ）×２．５６ｍｍＸ方向に送られる。
【００２３】
一方、倍密度の場合には、一方向の走査の後、半ピッチ分、すなわち２．５μｍ分Ｘ方向にヘッドを移動させて逆向きに走査することにより、前回の走査により形成されたドットとドットとの間をドットで埋めてゆく。このように半ピッチずらしてインターレースの手法で往復走査することにより１つの帯状の領域にパターンを描画する。全てのＬＥＤが描画に使用される場合、１０．２４ｍｍの幅に対して４０９６ドットの密度でデータを描画できる。走査方向に対しても２．５μｍピッチでドットを形成する場合、一往復の走査のデータ量は標準密度の４倍の１２８ＭＢとなり、８ＭＢのデータ容量でＹ列４列分、すなわち３２×４＝１２８個のＬＥＤを往復走査分制御することができる。倍密度の記録をする場合、描画データを送る側から見ると、１回の走査で４０４８個のＬＥＤを制御するのと等価であり、そのように考えると、８ＭＢのデータ容量でＹ列８列分、すなわち３２×８＝２５６個のＬＥＤを一走査分制御することとなる。
【００２４】
倍密度の場合には、ＬＥＤは１６のグループｇ1〜ｇ16に分類される。この場合、前述の第２の目的を達成するためには、１３６通りの組み合わせが考えられる。ただし、光源部の中心と投影レンズの光軸とが一致していることを前提にすると、第１の目的のためには以下の表２に示すａ〜ｈの８通りの組み合わせが選択できればよい。
【００２５】
【表２】

【００２６】
なお、光源部の中心と投影レンズの光軸とが一致しない場合には、不使用領域を表２に示すように左右対称(ｍ＝ｎ)だけではなく、非対称(ｍ≠ｎ)に定めてもよい。例えば、ｍ＝２，ｎ＝１としてグループｇ1，ｇ2，ｇ16を使用しないよう選択することができる。
【００２７】
倍密度で描画する場合、感光フィルム３の描画領域のＹ方向における端部から他の端部まで往復走査して帯状に画像が形成されると、光学ヘッド４を上記の使用されるグループの数に応じた描画幅分だけＸ方向に移動する。そして、光学ヘッド４の移動後にテーブル２をＹ方向に沿って移動することにより、同様にして、感光フィルム３にＹ方向に延びた帯状の画像を先に形成した領域に隣接して形成する。倍密度の場合、光学へッドはテーブルが一方の方向に走査する場合には走査が終了する毎に２．５μｍＸ方向に送られ、他方の方向に走査する場合には走査が終了する毎に１０．２４−（ｍ＋ｎ）×０．６４ｍｍＸ方向に送られる。
【００２８】
図５は、実施形態の記録装置１００の制御系を示すブロック図である。記録装置１００は、イーサネットのネットワークによりワークステーションＷＳと接続されており、ワークステーションＷＳから送られる描画データと制御情報とにしたがって感光フイルム３上にパターンを露光、描画する。ワークステーションＷＳから送られる描画データはベクトルデータであり、制御情報はドット間ピッチ、すなわち解像度と描画に使用しない光源のグループの番号ｍ，ｎとを含む。
【００２９】
描画装置１００の制御系は、イーサネットを介して入力されるワークステーションＷＳからのデータを受けるデータ入力インターフェイス(Ｉ／Ｆ)１０１と、この入力インターフェイスを介してベクトルデータとして入力される１画像分の全面の画像データが記憶される容量を持つバッファ１０２と、バッファ１０２に書き込まれたベクトルデータをビットマップのラスタデータに変換する演算処理回路１０３と、演算処理回路１０３により変換されたビットマップのデータが交互に書き込まれるそれぞれ８ＭＢの容量を持つ２つのバッファ１０４ａ，１０４ｂを備えるデータ書き込み回路１０４と、感光フィルム３上に形成される画像がポジ画像かネガ画像かにより描画データのビットを非反転または反転させるビット反転処理回路１０５と、走査により形成される１つの帯状の領域の描画データを保持するための１２８ＭＢの容量を持つ２つの画像メモリ１０６ａ，１０６ｂを備え、光学ヘッド４のＬＥＤの発光を制御する光源制御回路１０６とを備えている。
【００３０】
ワークステーションＷＳから入力される描画データの単位は、全領域をカバーする。この全領域はテーブル２を走査することにより形成される帯状の領域を複数合わせることによりカバーされる。バッファ１０２には、この全領域分の描画データが記憶される。
【００３１】
演算処理回路１０３は、変換したデータを２つのバッファ１０４ａ，１０４ｂに交互に書き込み、データ書き込み回路１０４は、演算処理回路１０３からのデータの転送が完了した一方のバッファのデータを光源制御回路１０６に出力し、その間他方のバッファには演算回路１０３からのデータが転送される。演算処理回路１０３から出力される描画データは、例えば感光フィルム上でプリント基板の導体パターンが形成される位置に対応するドットが「１」、他の領域が「０」となるよう定義づけられたポジ画像を基準とした二値データであり、光源制御回路１０６は、例えばデータが「１」のドットに対してはＬＥＤを発光させ、「０」のドットに対しては発光させない。
【００３２】
ビット反転処理回路１０５は、形成される画像がポジ画像である場合にはデータ書き込み回路１０４から出力される描画データをそのままＬＥＤ制御回路１０６に伝達し、ネガ画像である場合にはデータのビットを反転させて、すなわち、「１」のドットを「０」、「０」のドットを「１」に反転させて伝達する。
【００３３】
なお、演算処理回路１０３は、上記のようにデータを変換する機能のみでなく、他の回路を制御するＣＰＵとしての機能を有している。また、演算処理回路１０３は、グループ番号ｍ，ｎに基づいて求められる走査の描画幅と、描画データに含まれる位置情報とに基づいてテーブル２と光学ヘッド４との移動量を求める機能を有しており、求められた移動量データは、移動制御回路１１０へ出力され、移動量制御回路１１０はテーブル用ＡＣサーボ回路１１１と光学ヘッド用サーボ回路１１２とを介して光学系駆動モータ５Ｍとテーブル移動モータ２Ｍモータとを駆動して光学ヘッドとテーブルとを移動させる。駆動中は、スケール検出ヘッド５Ｄおよび２Ｄの出力が移動量制御回路１１０に入力されており、各モータ５Ｍ，２Ｍは検出される移動量に基づいてフィードバック制御される。
【００３４】
図６は、上記の制御系に含まれる画像メモリ１０６ａのメモリ空間を示す説明図である。標準密度の場合には、図６(ａ)に示されるように、８ＭＢづつに分割された４つのパーティションと呼ばれる領域により一走査に用いられる３２ＭＢのバンドと呼ばれる領域が構成される。この３２ＭＢの描画データにより、標準密度における一回の走査で２０４８個のＬＥＤが制御される。１つのパーティションは、５１２個のＬＥＤを一走査制御するための描画データを有し、各パーティションがＬＥＤの各グループＧ1〜Ｇ4に対応する。
【００３５】
一方、倍密度の場合には、図６(ｂ)に示されるように、８ＭＢづつに分割された１６のパーティションにより往復走査に用いられる１２８ＭＢのバンドが構成される。この場合、１つのパーティションは１２８個のＬＥＤを往復走査するために必要な描画データを保持し、各パーティションがＬＥＤの各グループｇ1〜ｇ16に対応する。
【００３６】
データ書き込み回路１０４は、２つのバッファ１０４ａ，１０４ｂからデータを交互に出力してパーティション単位で描画データをＬＥＤ制御回路１０６の画像メモリ１０６ａ，１０６ｂに書き込む。なお、特定のグループのＬＥＤを描画に使用しないことは、これらのＬＥＤにより形成され得る全ドットに対して「非発光」というデータを入力することに等しい。そこで、ｍ，ｎの数値に応じ、使用されない光源のグループに対応するデータが書き込まれるパーティションには、演算処理回路１０３から入力される描画データではなく、「非発光」を意味する一定のデータが書き込まれる。ただし、データ書き込み回路１０４から出力されるデータは、形成される画像がネガ画像の場合にはビット反転回路１０５により反転されるため、いずれの場合にも画像メモリ１０６ａ，１０６ｂに書き込まれるデータが「非発光」を意味する「０」となるように、ポジ画像の場合には該当するパーティションに転送されるべきバッファ１０４ａ，１０４ｂの全てのビットが「０」で埋められ、ネガ画像の場合には「１」で埋められる。
【００３７】
図７および図８は、１画面分のパターンを描画するための演算処理回路１０３による制御の手順を示すフローチヤートである。ここでは、倍密度で記録する場合、すなわち、１バンドが１６パーティションで構成される場合を例にして説明する。
ステップ(図中「S.」で示す)１、２でワークステーションＷＳから制御情報と描画データとを受信すると、ステップ３において描画データに含まれる位置情報に基づいて光学ヘッド４およびデーブル２の初期位置を求めて移動制御回路１１０へ出力する。移動制御回路１１０は、この情報に基づいて光学系駆動モータ５Ｍとテーブル移動モータ２Ｍとを駆動する。
【００３８】
ステップ４では、描画に用いられない光源のグループ数ｍ，ｎを全グループ数１６から差し引いて描画に用いられる光源のグループ数ｐを求める。標準密度の場合には、ｐは(４−ｍ−ｎ)で求められる。ステップ５〜１０では、描画に用いられない一方側の光源グループに対応する画像メモリ上のｍ個のパーティションに「非発光」のデータが書き込まれる。「非発光」のデータは、上述のようにポジ画像を形成する場合には「０」、ネガ画像を形成する場合には「１」となるため、対応する値を書き込む。
【００３９】
ステップ１１〜１４は、描画に用いられる光源のグループに対応する画像メモリ上のパーティションに描画データを書き込む処理である。続く図８のステップ１５〜２０では、描画に用いられない他方側の光源グループに対応する画像メモリ上のｎ個のパーティションに「非発光」のデータが書き込まれる。
【００４０】
上記の処理により画像メモリ１０６ａの１２８ＭＢの領域に倍密度の往復走査分のデータが書き込まれると、ステップ２１でテーブルをＹ方向に移動させながら各ＬＥＤを発光制御してパターンを描画する。１つの帯状の描画領域分の描画が終了すると、描画データが残っている場合にはステップ２３で光学ヘッド４を移動させて図７のステップ５に戻り、次の帯状の描画領域の描画を開始する。描画データが終了すると１画面分の描画が終了する。
なお、このフローチャートでは、ステップ２１の実際の描画処理とステップ５〜２０の画像メモリへのデータの書き込みとが時系列的に順に実行させるように示されているが、一方の画像メモリ１０６ａに記憶された描画データによりパターンが描画されている間に、他方の画像メモリ１０６ｂへ描画データが書き込まれる。これにより、１つの帯状の描画領域から次の領域の描画を開始するまでの時間を短縮することができる。
【００４１】
【発明の効果】
以上説明したように、この発明によれば、投影光学系の収差が大きく影響する光軸から離れた光源を利用せずに中心部の光源のみを用いて描画することにより、各光源からの光束により形成されるドットの位置精度を高めることができ、投影光学系の性能を高めることなく高い精度の描画が可能となる。
また、複数の光源の一部が断線等により発光不能となった場合には、その光源を含む光源のグループを使用せずに描画することができ、光学ヘッドを修理、交換するまでの間も装置を利用することが可能となる。
【図面の簡単な説明】
【図１】 実施形態にかかるマルチビーム記録装置の外観を示す斜視図である。
【図２】 光学ヘッドの構成の概略を示す側面図である。
【図３】 アパーチャパネルを光学ヘッドの上面側から見た図である。
【図４】 感光フィルム上に結像した点像のパターンを示す図である。
【図５】 実施形態の装置の制御系を示すブロック図である。
【図６】 ＬＥＤ制御回路に含まれる画像メモリのメモリ空間を示す説明図である。
【図７】 演算処理回路の制御の手順の前半を示すフローチヤートである。
【図８】 演算処理回路の制御の手順の後半を示すフローチヤートである。
【符号の説明】
２ テーブル
４ 光学ヘッド
４２ ＬＥＤ
４３ アパーチャー板
４４,４５ 第１、第２レンズ群(投影光学系)
１００ パターン記録装置
１０３ 演算処理回路
１０４ データ書き込み回路
１０４ａ，１０４ｂ バッファ
１０６ 光源制御回路
１０６ａ，１０６ｂ 画像メモリ[0001]
[Industrial application fields]
The present invention projects a light beam from a light source section having a plurality of light sources arranged two-dimensionally onto a drawing surface by a projection lens, and draws an image by relatively scanning the light source image and the drawing surface. The present invention relates to a multi-beam recording apparatus.
[0002]
[Prior art]
Japanese Patent Application Laid-Open No. 6-186490 has a light source unit including a semiconductor laser arrayed as a two-dimensional matrix and a corresponding aperture, and an image of this aperture is formed as a dot on a drawing surface by a projection optical system. A beam recording apparatus is disclosed. This apparatus controls the semiconductor laser while relatively scanning the drawing surface and the aperture image, and shifts the aperture image of each row discretely arranged in a direction orthogonal to the scanning direction while shifting the aperture image by a predetermined pitch. By overlapping, a two-dimensional image is formed on the drawing surface.
[0003]
[Problems to be solved by the invention]
However, since this type of multi-beam recording apparatus uses a large-diameter projection lens to reduce and project the aperture pattern onto the drawing surface, the amount of aberration generated at the periphery of the lens becomes relatively large. As for the aperture in the peripheral part away from the optical axis, the shape of the image (dot) of the aperture projected on the drawing surface is distorted, or the position of the dot deviates from the planned position. Such distortion and displacement of the aperture image do not pose a problem when the resolution of the formed image is low, but when the resolution is high, precise drawing is hindered and becomes a problem.
[0004]
An object of the present invention is to provide a multi-beam recording apparatus capable of performing precise drawing even when a projection lens having aberration is used in view of the above-described problems of the prior art.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the multi-beam recording apparatus according to the present invention is characterized in that the scanning width can be changed by selecting a light source used for drawing from a plurality of light sources arranged in two dimensions. To do. According to such a configuration, when the resolution is low, a pattern can be formed over a wide range by one scan using all the light sources, and when the resolution is high, a peripheral light source away from the optical axis of the projection optical system can be formed. A pattern with high accuracy can be formed by drawing using only the light source in the central part, which is less influenced by aberration, without using it.
[0006]
That is, a multi-beam recording apparatus according to the present invention includes a light source unit in which a plurality of light sources having an effective area are two-dimensionally arranged discretely, a projection optical system that forms dots on a drawing surface by a light beam emitted from the light source, and A first moving means for forming a strip-like drawing area on the drawing surface by relatively moving the light source unit and the drawing surface along the first direction during the drawing period; and during the non-drawing period. A second moving means for switching the drawing area by the first moving means by moving the light source part and the drawing surface relatively along a second direction perpendicular to the first direction; and the light source part The light source is classified into a plurality of groups by boundary lines parallel to the first direction, and the light source used for drawing and the light source not used are selected in units of groups to set the width of the drawing area and for drawing. Unused glue The drawing control means for controlling the light emission and non-light emission of the light sources of the group used for drawing based on the inputted drawing data without turning on the light source, and the drawing by the second moving means according to the width of the drawing area A moving amount changing unit that changes a moving amount at the time of switching the area, and the drawing control unit selects one or a plurality of groups respectively located outside both of the light sources as a group that is not used for drawing. In addition, the drawing is performed without using light using a region having a large influence of the aberration outside the projection optical system .
[0007]
The drawing control means also includes an arithmetic processing circuit that forms a bitmap based on input drawing data, an image memory that stores control data for the total number of light sources corresponding to a single scanning area, and is used for drawing. Write the bitmap drawing data to the image memory as the light source control data for the group to be written, and write to the image memory the non-light emitting data to the image memory as the control data for the light source of the group not used for drawing It is desirable to include a light source driving circuit for driving the light source unit based on the data.
[0008]
Further, in this case, the data writing circuit includes two buffers for storing the control data included in one scanning region in units of light source groups, writing bitmap data and non-light-emitting data, and a memory for these data It is possible to configure so as to alternately execute the discharging to the two buffers.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a multi-beam recording apparatus according to the present invention will be described below. FIG. 1 is a perspective view illustrating an appearance of a multi-beam recording apparatus 100 according to the embodiment. The multi-beam recording apparatus 100 of the embodiment is an apparatus that records a circuit pattern on a mask for exposure printing for creating a printed circuit board.
[0010]
The multi-beam recording apparatus 100 has an apparatus main body base 1, a photosensitive film 3 as a drawing surface on which a circuit pattern is drawn, a table 2 that can slide in the Y direction with respect to the apparatus main body base 1, and a photosensitive film. 3 is composed of an optical head 4 that forms a projection pattern on 3 and an optical base 5 that slidably supports the optical head 4 in the X direction perpendicular to the Y direction relative to the main body base 1.
[0011]
The table 2 is rotated with respect to the light source image formed by the optical head 4 by rotating the ball screw 2B with a table drive motor (not shown) with its lower surface guided along a pair of rails 2R extending in the Y direction. The photosensitive film 3 is scanned in the Y direction. A first moving means for linearly moving the photosensitive film 3 as the drawing surface relative to the light source image in the Y direction, which is the first direction, by the ball screw 2B and the table drive motor. Composed.
[0012]
The optical base 5 is guided by a pair of guide rails 5R extending in the X direction and can move in the X direction. The optical head 4 is moved in the X direction by rotating the ball screw 5B by the optical system drive motor 5M. Move. The optical system drive motor 5M and the ball screw 5B constitute second moving means for relatively moving the light source image and the drawing surface along a direction different from the Y direction. The second moving means linearly moves the optical head 4 in the second direction (X direction) orthogonal to the first direction (Y direction) during the non-drawing period, thereby drawing the drawing area by the first moving means. Has a function of switching.
[0013]
The optical head 4 is provided with a scale detection head 5D for detecting a position detection linear scale 5K provided on the apparatus body base 1, and the optical system drive motor 5M is fed back based on the detection signal of the scale detection head 5D. Be controlled. Although not shown, the table 2 includes a similar detection mechanism, and the table drive motor is feedback-controlled based on the detection result.
[0014]
FIG. 2 is a side view showing an outline of the optical system of the optical head 4. The optical head 4 includes a light source unit in which a plurality of light sources having an effective area are discretely arranged two-dimensionally, and a projection optical system that forms an image of the light source on a drawing surface. The light source unit includes an LED (light emitting diode) 42 which is a light emitting element attached to the printed circuit board 41, and an aperture plate 43 on which an aperture AP located in front of the LED 42 is formed. The projection optical system is a reduction optical system with a magnification of 1/25, which is composed of a first lens group 44 and a second lens group 45 arranged in order from the aperture plate 43 side, and an image of the aperture AP by a beam transmitted through the aperture plate 43. Are formed on the surface of the photosensitive film 3 as dots.
[0015]
FIG. 3 is a view of the aperture panel 43 as viewed from the upper surface side of the optical head 4 for explaining the arrangement of the apertures formed on the LEDs 42 and the aperture panel 43 (viewed from the upper side in FIG. 2). . The position of the LED 42 is indicated by a broken line. In the present embodiment, 2048 LEDs 42 are two-dimensionally arranged. Thirty-two LEDs 42 are arranged in the Y direction (hereinafter, the LEDs 42 arranged in the Y direction are referred to as Y columns of LEDs 42). Similarly, 64 rows of LEDs 42 arranged in the Y direction are arranged in the X direction. When attention is paid to one line in the X direction, the 64 LEDs 42 are aligned along the X direction (hereinafter, the LEDs aligned in the X direction are referred to as X rows of LEDs). The LED 42 has a maximum diameter of 3.8 mm on a plane parallel to the photosensitive film 3. In order to arrange them so as not to contact each other, as shown in FIG. 3, the LEDs 42 are arranged at intervals of 4 mm in each of the X direction and the Y direction. As shown by Y1 to Y32 in FIG. 3, the Y rows of LEDs are sequentially arranged at positions shifted by the diameter of the aperture AP, and the aperture AP is also formed in a similar arrangement. The distance between Y1 and Y33 is 4 mm, and the diameter of the aperture AP is 0.125 mm.
[0016]
FIG. 4 is a diagram showing dots corresponding to each beam on the photosensitive film 3, that is, an image of the aperture panel 43. In the figure, the black dots are dots by which the film 3 is exposed by the beam. FIG. 4 is a diagram for illustrating the arrangement of dots, and the size of each part is not shown in the correct scale. The dot formation range on the photosensitive film 3 is 10.24 mm in the X direction and 4.96 mm in the Y direction.
[0017]
When drawing, the LED is controlled to emit light while moving the table 2 in the Y direction, and an image is formed on the surface of the photosensitive film 3 in a band-like region extending in the Y direction. Accordingly, when attention is paid to a certain line (a line along the X direction), all the images (dots) of the LED beams are arranged in a line at a pitch of a distance of 5 μm between the centers in one scan. If all the LEDs are used for drawing, a strip-like drawing area having a width of 10.24 mm is formed on the photosensitive film 3 by scanning the table. However, in the apparatus of the embodiment, the width of the band-like drawing area can be changed.
[0018]
In order to change the width of the drawing area, that is, to select the LEDs used for drawing, all the LEDs are classified into a plurality of groups by the boundary line in the Y direction. The classification is changed according to the resolution with reference to 8 MB, which is the minimum unit of drawing data that can be processed by the processing device at a time. The apparatus of the embodiment is configured such that the resolution can be selected between a standard dot density of 5 μm between dots and a double density of 2.5 μm.
[0019]
In the case of the standard density, one band-like region is drawn by one scan as described above. In this case, the light emission timing of each LED is also determined so that the dot pitch is 5 μm in the Y direction. At the standard density, the data amount of one scan is 32 MB (megabytes), and the data capacity of 8 MB can control 16 columns of Y columns, that is, 32 × 16 = 512 LEDs for one scan. Therefore, in this case, the LEDs are classified into four groups G1 to G4. Of these groups, one of the central groups G2 and G3 is always used for drawing, and the outer groups G1 and G4 are used for drawing by selection or not used. Therefore, 10 combinations of A to J shown in Table 1 below can be considered. In Table 1, the used group is represented by ◯, the unused group is represented by ×, and the number of light source groups not used for drawing is represented by numbers m and n. Here, m is the number of light source groups that are not used for drawing on one side in the width direction of the drawing area, and the mth group from the outside is not used for drawing. Similarly, n is the number of light source groups not used for drawing on the other side in the width direction of the drawing area.
[0020]
[Table 1]

[0021]
For changing the drawing width, when high drawing accuracy is required, only the light that passes through the center of the projection lens is used without using the light that uses the area outside the projection lens where the influence of the aberration is large. The second purpose is to prevent dot dropout by drawing without using a group including the LED when any LED becomes incapable of light emission due to disconnection or the like. is there. In order to achieve the first object, it is necessary to draw using only the LED corresponding to the central region without using the LED corresponding to the outer region in the width direction. In this case, it is sufficient if two combinations of A and F can be selected. However, in order to achieve the second object, it is desirable that other combinations of B to E and G to J can be selected.
[0022]
When drawing at a standard density, when an image is formed in a strip shape from the end in the Y direction of the drawing area of the photosensitive film 3 to another end, the optical head 4 is drawn according to the number of groups used. Move in the X direction by the width. Then, by moving the table 2 in the opposite direction (along the Y direction) after the movement of the optical head 4, a band-shaped image extending in the Y direction is formed on the photosensitive film 3 in the same manner. It is formed adjacent to the region. In the case of the standard density, the optical head is sent in the 10.24- (m + n) × 2.56 mmX direction every time scanning is completed, regardless of which direction the table is scanned.
[0023]
On the other hand, in the case of double density, after scanning in one direction, by moving the head in the X direction by half a pitch, that is, 2.5 μm, and scanning in the reverse direction, Fill the dots with dots. In this way, a pattern is drawn in one band-like region by reciprocating scanning by an interlace method with a half pitch shift. When all LEDs are used for drawing, data can be drawn at a density of 4096 dots for a width of 10.24 mm. When dots are formed at a pitch of 2.5 μm in the scanning direction, the amount of data for one reciprocal scanning is 128 MB, which is four times the standard density, and the data capacity is 8 MB for four Y columns, that is, 32 × 4 = 128 LEDs can be controlled for reciprocal scanning. When double-density recording is performed, it is equivalent to controlling 4048 LEDs in one scan when viewed from the drawing data sending side. Considering this, 8 rows of Y columns with a data capacity of 8 MB are considered. That is, 32 × 8 = 256 LEDs are controlled for one scan.
[0024]
In the case of double density, the LEDs are classified into 16 groups g1 to g16. In this case, in order to achieve the second object, 136 combinations are conceivable. However, assuming that the center of the light source unit and the optical axis of the projection lens coincide with each other, it is only necessary to select eight combinations a to h shown in Table 2 below for the first purpose. .
[0025]
[Table 2]

[0026]
When the center of the light source unit and the optical axis of the projection lens do not coincide with each other, the unused area is determined not only to be symmetric (m = n) but also to asymmetric (m ≠ n) as shown in Table 2. Also good. For example, it is possible to select not to use the groups g1, g2, and g16 with m = 2 and n = 1.
[0027]
In the case of drawing at double density, when an image is formed in a strip shape by reciprocating scanning from the end in the Y direction of the drawing area of the photosensitive film 3 to the other end, the number of the groups used is the optical head 4. Move in the X direction by the drawing width corresponding to. Then, by moving the table 2 along the Y direction after the optical head 4 is moved, a strip-like image extending in the Y direction is similarly formed on the photosensitive film 3 adjacent to the previously formed region. In the case of double density, the optical head is sent in the direction of 2.5 μm X every time scanning is finished when the table is scanned in one direction, and every time scanning is finished when scanning in the other direction. 10.24- (m + n) × 0.64 mm sent in the X direction.
[0028]
FIG. 5 is a block diagram illustrating a control system of the recording apparatus 100 according to the embodiment. The recording apparatus 100 is connected to the workstation WS via an Ethernet network, and exposes and draws a pattern on the photosensitive film 3 in accordance with drawing data and control information sent from the workstation WS. The drawing data sent from the workstation WS is vector data, and the control information includes the dot pitch, that is, the resolution and the numbers m and n of light source groups not used for drawing.
[0029]
The control system of the drawing apparatus 100 includes a data input interface (I / F) 101 that receives data from the workstation WS that is input via Ethernet, and one image that is input as vector data via the input interface. A buffer 102 having a capacity for storing the entire image data, an arithmetic processing circuit 103 that converts vector data written in the buffer 102 into bitmap raster data, and bitmap data converted by the arithmetic processing circuit 103 The data writing circuit 104 having two buffers 104a and 104b each having a capacity of 8 MB to be written alternately, and the bits of the drawing data are non-inverted depending on whether the image formed on the photosensitive film 3 is a positive image or a negative image. Bit inversion processing circuit 105 to invert A light source control circuit 106 that includes two image memories 106 a and 106 b having a capacity of 128 MB for holding drawing data of one band-like area formed by scanning, and controls the light emission of the LED of the optical head 4. I have.
[0030]
The unit of drawing data input from the workstation WS covers the entire area. This entire area is covered by combining a plurality of band-like areas formed by scanning the table 2. The buffer 102 stores drawing data for the entire area.
[0031]
The arithmetic processing circuit 103 alternately writes the converted data to the two buffers 104a and 104b, and the data writing circuit 104 sends the data of one buffer for which data transfer from the arithmetic processing circuit 103 is completed to the light source control circuit 106. In the meantime, the data from the arithmetic circuit 103 is transferred to the other buffer. The drawing data output from the arithmetic processing circuit 103 is defined such that, for example, the dot corresponding to the position where the printed circuit board conductor pattern is formed on the photosensitive film is “1” and the other areas are “0”. For example, the light source control circuit 106 causes the LED to emit light for a dot whose data is “1” and does not cause it to emit light for a dot “0”.
[0032]
When the formed image is a positive image, the bit inversion processing circuit 105 transmits the drawing data output from the data writing circuit 104 to the LED control circuit 106 as it is, and when it is a negative image, the bit inversion data is transmitted. In other words, the dot “1” is transferred to “0” and the dot “0” is transferred to “1”.
[0033]
Note that the arithmetic processing circuit 103 has not only a function of converting data as described above but also a function of a CPU that controls other circuits. Further, the arithmetic processing circuit 103 has a function of obtaining the movement amount between the table 2 and the optical head 4 based on the scanning drawing width obtained based on the group numbers m and n and the position information included in the drawing data. The obtained movement amount data is output to the movement control circuit 110. The movement amount control circuit 110 is connected to the optical system drive motor 5M and the table via the table AC servo circuit 111 and the optical head servo circuit 112. The moving motor 2M motor is driven to move the optical head and the table. During driving, the outputs of the scale detection heads 5D and 2D are input to the movement amount control circuit 110, and the motors 5M and 2M are feedback-controlled based on the detected movement amounts.
[0034]
FIG. 6 is an explanatory diagram showing a memory space of the image memory 106a included in the control system. In the case of the standard density, as shown in FIG. 6A, an area called a 32 MB band used for one scan is constituted by an area called 4 partitions divided by 8 MB. With this 32 MB drawing data, 2048 LEDs are controlled by one scan at the standard density. One partition has drawing data for performing one-scan control of 512 LEDs, and each partition corresponds to each group G1 to G4 of LEDs.
[0035]
On the other hand, in the case of double density, as shown in FIG. 6 (b), a 128 MB band used for reciprocal scanning is constituted by 16 partitions divided into 8 MB. In this case, one partition holds drawing data necessary for reciprocating scanning of 128 LEDs, and each partition corresponds to each group of LEDs g1 to g16.
[0036]
The data writing circuit 104 alternately outputs data from the two buffers 104a and 104b and writes drawing data to the image memories 106a and 106b of the LED control circuit 106 in units of partitions. Note that not using a specific group of LEDs for drawing is equivalent to inputting “non-light-emitting” data for all dots that can be formed by these LEDs. Therefore, according to the values of m and n, in the partition in which data corresponding to a group of light sources that are not used is written, not the drawing data input from the arithmetic processing circuit 103 but constant data that means “non-light emission”. Written. However, since the data output from the data writing circuit 104 is inverted by the bit inversion circuit 105 when the formed image is a negative image, the data written to the image memories 106a and 106b is “ In the case of a positive image, all the bits of the buffers 104a and 104b to be transferred to the corresponding partition are filled with “0” so as to be “0” meaning “non-light emission”. Filled with “1”.
[0037]
7 and 8 are flowcharts showing the control procedure by the arithmetic processing circuit 103 for drawing a pattern for one screen. Here, a case where recording is performed at double density, that is, a case where one band is composed of 16 partitions will be described as an example.
When control information and drawing data are received from the workstation WS at steps (indicated by “S.” in the figure) 1 and 2, the initial state of the optical head 4 and the table 2 is determined based on the position information included in the drawing data at step 3. The position is obtained and output to the movement control circuit 110. The movement control circuit 110 drives the optical system drive motor 5M and the table movement motor 2M based on this information.
[0038]
In step 4, the number of light source groups m and n not used for drawing is subtracted from the total number of groups 16 to obtain the number of light source groups p used for drawing. In the case of standard density, p is determined by (4-mn). In Steps 5 to 10, “non-light-emitting” data is written in m partitions on the image memory corresponding to the light source group on one side not used for drawing. The “non-light emission” data is “0” when a positive image is formed as described above, and “1” when a negative image is formed, and therefore a corresponding value is written.
[0039]
Steps 11 to 14 are processes for writing drawing data to a partition on the image memory corresponding to a group of light sources used for drawing. In subsequent steps 15 to 20 in FIG. 8, “non-light-emitting” data is written in n partitions on the image memory corresponding to the light source group on the other side not used for drawing.
[0040]
When the double-density reciprocating scan data is written in the 128 MB area of the image memory 106a by the above processing, in step 21, the LED is controlled to emit light while moving the table in the Y direction, and a pattern is drawn. When drawing for one band-like drawing area is completed, if drawing data remains, the optical head 4 is moved in step 23 and the process returns to step 5 in FIG. 7 to start drawing the next band-like drawing area. To do. When drawing data is finished, drawing for one screen is finished.
In this flowchart, the actual drawing process in step 21 and the writing of data to the image memory in steps 5 to 20 are shown to be executed sequentially in time series, but stored in one image memory 106a. While the pattern is drawn with the drawn data, the drawing data is written to the other image memory 106b. As a result, it is possible to shorten the time from the start of drawing of the next area from one band-like drawing area.
[0041]
【The invention's effect】
As described above, according to the present invention, the light flux from each light source is drawn by using only the light source in the central portion without using the light source away from the optical axis that greatly affects the aberration of the projection optical system. As a result, the positional accuracy of the dots formed can be improved, and high-accuracy drawing can be performed without increasing the performance of the projection optical system.
In addition, when some of the light sources are unable to emit light due to disconnection, etc., drawing can be performed without using a group of light sources including the light source, and until the optical head is repaired or replaced. The device can be used.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating an appearance of a multi-beam recording apparatus according to an embodiment.
FIG. 2 is a side view schematically showing the configuration of an optical head.
FIG. 3 is a view of an aperture panel as viewed from the upper surface side of the optical head.
FIG. 4 is a diagram showing a pattern of point images formed on a photosensitive film.
FIG. 5 is a block diagram illustrating a control system of the apparatus according to the embodiment.
FIG. 6 is an explanatory diagram showing a memory space of an image memory included in the LED control circuit.
FIG. 7 is a flowchart showing the first half of the control procedure of the arithmetic processing circuit.
FIG. 8 is a flowchart showing the second half of the control procedure of the arithmetic processing circuit.
[Explanation of symbols]
2 Table 4 Optical head 42 LED
43 Aperture plates 44, 45 First and second lens groups (projection optical system)
100 pattern recording device 103 arithmetic processing circuit 104 data writing circuit 104a, 104b buffer 106 light source control circuit 106a, 106b image memory

Claims (5)

A light source unit in which a plurality of light sources having an effective area are discretely arranged two-dimensionally;
A projection optical system that forms dots on the drawing surface by the light flux from the light source;
First moving means for forming a strip-shaped drawing region on the drawing surface by relatively linearly moving the light source unit and the drawing surface along a first direction during a drawing period;
During the non-drawing period, the light source unit and the drawing surface are moved relative to each other along a second direction perpendicular to the first direction, thereby switching a drawing region by the first moving unit. Two moving means;
The light sources of the light source unit are classified into a plurality of groups by boundary lines parallel to the first direction, and the width of the drawing region is set by selecting light sources used for drawing and light sources not used for drawing in units of groups. And drawing control means for controlling the light emission and non-light emission of the light sources of the group used for drawing based on the input drawing data without turning on the light sources of the group not used for drawing,
A moving amount changing means for changing a moving amount at the time of switching the drawing area by the second moving means according to the width of the drawing area;
In the light source, the drawing control unit selects one or a plurality of groups located outside both of the light sources as a group not used for drawing, thereby using a region where the influence of the aberration outside the projection optical system is large. A multi-beam recording apparatus for performing drawing without using light to be emitted .   2. The multi-beam recording apparatus according to claim 1, wherein the drawing control unit selects an equal number of groups on both sides of the light source group as a group not used for drawing. 3. The drawing control means includes: an arithmetic processing circuit that forms a bitmap based on input drawing data; an image memory that stores control data for the total number of the light sources corresponding to a single drawing area; A data writing circuit for writing drawing data of the bitmap to the image memory as control data of the light source of the group to be used, and writing non-light-emitting data to the image memory as control data of the light source of the group not used for drawing, multibeam recording apparatus according to claim 1 or claim 2, characterized in that it comprises a light source driving circuit for driving the light source unit based on the data written in the memory. The data writing circuit includes two buffers for storing control data included in one drawing area in units of light source groups, writing the bitmap drawing data and the non-light-emitting data, and writing the data 4. The multi-beam recording apparatus according to claim 3 , wherein the discharge to the image memory is executed alternately by the two buffers. The number of light sources included in the group, the multi-beam recording apparatus according to claim 2 or claim 3, characterized in that it is changed according to the size of the drawing data necessary for controlling the light source in the group .

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