JPH0713680A - Interpolating method for coordinate detecting device - Google Patents

Abstract

PURPOSE:To attain precise coordinate discrimination by performing the arithmetic interpolation of coordinates from two levels under consideration of signal detection levels from adjacent electrode lines which are the second and third nearest from a detecting pen. CONSTITUTION:X and Y-direction analog multiplexers 8 and 9 impress an inter- two electrode balanced voltage signal to a balance/imbalance converter 10, only the basic components of a sine wave are allowed to pass through a band pass filter 11, and transmitted to a control part 12. At the time of correcting the position between the electrode lines from the signal detection level, the control part 12 decides the inter-electrode line abutted position of a detection pen 2 to a table l from an approximate interpolating amount X obtained from an expression X=(d/2)X2.5(S23-S01)/(S23+S01) by using interpolating characteristic decided by an electrode line 7, two conductors 5 and 6 at the top end of the detection pen 2, and a physical size. In the expression, (d) is an inter- electrode line interval, S01 is the signal detection level obtained from the (n)th and the (n+1)th electrode lines at the time of defining (n) as the arbitrary electrode line, and S23 is the signal detection level obtained from the (n+2)th and the (n+3)th electrode lines.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】 本発明はタブレット上に当接さ
れたケーブル無しの検出ペンの、タブレットへの当接位
置情報をデジタル値で出力する座標検出装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate detection device for outputting, as a digital value, contact position information of a detection pen without a cable contacted on a tablet with the tablet.

【０００２】[0002]

【従来の技術】 装置本体とのケーブル無しの静電容量
結合方式での能動回路を内蔵した検出ペンを使用したタ
ブレット座標検出装置においては、平衡一信号伝達のた
めの隣接電極二本を同時使用する平衡不平衡変換による
場合、信号検出レベル特性曲線は二山特性を示すが、こ
の特性から補間法により精密な座標を算出するに当たり
従来は検出ペンに一番近い隣接二電極線からの信号レベ
ルのみに主に注目した計算と補正を行い座標出力してい
た。2. Description of the Related Art In a tablet coordinate detection device that uses a detection pen that incorporates an active circuit in a capacitive coupling method without a cable with the device body, two adjacent electrodes for balanced and one signal transmission are used simultaneously. In the case of balanced / unbalanced conversion, the signal detection level characteristic curve shows two peak characteristics, but when calculating precise coordinates from this characteristic by the interpolation method, the signal level from the adjacent two-electrode line closest to the detection pen was conventionally used to calculate precise coordinates. The calculations and corrections were mainly focused on, and the coordinates were output.

【０００３】[0003]

【発明が解決しようとする課題】 前記した従来の補間
算出手段では物理的各部寸法及び電気回路の部品のバラ
ツキにより座標出力の連続性が隣接電極線の中間点で均
一ではなかった。また更に電極線位置での信号検出レベ
ル特性曲線の傾きがゆるやかであり、位置変化量に対す
る検出レベル変化量が少なく、位置判定精度が他の位置
に比し低下していた。In the above-described conventional interpolation calculation means, the continuity of coordinate output is not uniform at the midpoints of the adjacent electrode lines due to variations in the physical dimensions of each part and the parts of the electric circuit. Furthermore, the slope of the signal detection level characteristic curve at the electrode line position is gentle, the amount of change in the detected level with respect to the amount of position change is small, and the position determination accuracy is lower than at other positions.

【０００４】[0004]

【課題を解決するための手段】 本発明は従来の問題に
鑑みなされたもので、Ｘ及びＹ座標軸に沿って配設され
た複数の電極線を有するタブレットと、該タブレットの
電極線とそれぞれ静電容量結合する二つの導体を先端部
に配置した検出ペンと、前記電極線の隣合う二本からの
信号を平衡入力し順次切り換え接続し二線平衡信号出力
するアナログマルチプレクサと、該アナログマルチプレ
クサからの平衡信号を不平衡信号に変換する平衡不平衡
変換器と、該平衡不平衡変換器からの不平衡信号を印加
されるバンドパスフィルタと、該バンドパスフィルタを
介して信号を印加される信号検出及び制御部とを有し、
前記検出ペン内部に電源部と検出ペン先端部の二つの導
体へ平衡接続された正弦波、矩形波等の交番信号発生器
等が配置され、前記電極線の隣接電極線毎の平衡信号電
圧レベルを計測することによって、タブレットへの検出
ペンの当接位置座標を出力する座標検出装置において、
検出信号レベルから電極線間の位置を補間するにあた
り、 Ｘ＝（ｄ／２）×２．５（Ｓ23−Ｓ01）／（Ｓ23＋Ｓ01）・・・式１ の式１により得られた近似補間量Ｘを用い、または更に
この近似値を前記電極線と前記検出ペン先端部の二つの
導体との物理的各寸法により決まる補正特性とを用いる
事による、前記タブレットへの前記検出ペンの電極線間
当接位置座標を詳細に決定するための補間方法を提案す
るものである。但し、 ｄ＝電極線間隔 Ｓ01＝ｎを任意番目の電極線としたときのｎとｎ＋１番
目の電極線による信号検出レベル Ｓ23＝ｎ＋２とｎ＋３番目の電極線による信号検出レベ
ルである。Means for Solving the Problems The present invention has been made in view of the problems of the related art, and a tablet having a plurality of electrode lines arranged along the X and Y coordinate axes, and the electrode lines of the tablet, respectively. From a detection pen in which two conductors that are capacitively coupled are arranged at the tip end, an analog multiplexer that balanced-inputs signals from two adjacent electrode lines and sequentially switches and connects them to output a two-wire balanced signal, and from the analog multiplexer Unbalanced converter for converting a balanced signal of the above into an unbalanced signal, a bandpass filter to which the unbalanced signal from the balanced and unbalanced converter is applied, and a signal to which a signal is applied via the bandpass filter Has a detection and control unit,
Inside the detection pen, an alternating signal generator such as a sine wave and a rectangular wave, which is balanced-connected to the two conductors of the power supply section and the tip of the detection pen, is arranged. In the coordinate detection device that outputs the contact position coordinates of the detection pen on the tablet by measuring
In interpolating the position between the electrode lines from the detection signal level, X = (d / 2) × 2.5 (S23−S01) / (S23 + S01) ... Approximate interpolation amount X obtained by Equation 1 of Equation 1 , Or by using this approximation value as a correction characteristic determined by the physical dimensions of the electrode wire and the two conductors of the tip of the detection pen. The present invention proposes an interpolation method for determining the contact point coordinates in detail. However, d = interval between electrode lines S01 = signal detection level by the nth and n + 1th electrode lines when Sn = n is an arbitrary electrode line S23 = n + 2 and a signal detection level by the n + 3rd electrode line.

【０００５】[0005]

【作用】 検出ペンから二番目及び三番目に近い隣接電
極線からの信号検出レベルに注目した二レベルから座標
の補間計算を行うもので、上記二つの信号検出レベル特
性により出来る２個の近似三角形を使用して補間計算
し、その後電極線と検出ペン先端部の二つの導体との物
理的各寸法により決まる補正特性により補正し精密な座
標判定を行う。The coordinate interpolation calculation is performed from the two levels focusing on the signal detection levels from the second and third adjacent electrode lines from the detection pen. Two approximate triangles formed by the above two signal detection level characteristics. Then, interpolation calculation is performed by using, and then the coordinate is corrected by the correction characteristic determined by the physical dimensions of the electrode wire and the two conductors at the tip of the detection pen to make a precise coordinate determination.

【０００６】[0006]

【実施例】 以下本発明の詳細を添付図を参照して説明
する。図１は平衡信号伝達手段を利用した装置の構成図
を兼ねた電気信号系統図である。検出ペン２内部に能動
回路の正弦波発生器３が配置され連続した正弦波等電圧
を発生する。この正弦波発生器３の平衡出力は検出ペン
２の先端部の二つの導体としてのスタイラス導体５及び
これを囲繞するリング状導体６へそれぞれ印加される。
電源部としての電池４はペン内部へ動作電力を供給す
る。The details of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an electric signal system diagram which also serves as a configuration diagram of an apparatus using a balanced signal transmission means. An active circuit sine wave generator 3 is arranged inside the detection pen 2 to generate a continuous sine wave equal voltage. The balanced output of the sine wave generator 3 is applied to the stylus conductor 5 as the two conductors at the tip of the detection pen 2 and the ring-shaped conductor 6 surrounding the stylus conductor 5.
The battery 4 as a power source supplies operating power to the inside of the pen.

【０００７】検出ペン２の先端部のスタイラス導体５及
びリング状導体６はタブレット１の盤面近くにある時、
タブレット１の各電極線７、７、７・・・と小容量の静
電容量結合することになる。従って、検出ペン２の先端
部のスタイラス導体５とリング状導体６間の電気信号は
タブレット１の各電極線７、７、７・・・に結合容量の
大きさに従ったレベルでそれぞれ伝わる。Ｘ方向及びＹ
方向アナログマルチプレクサ８及び９は各電極線７、
７、７・・・の隣合う二電極をペアーとしながら順次切
り換えて、それぞれの二電極線間平衡電圧信号を平衡不
平衡変換器１０へ印加する。When the stylus conductor 5 and the ring-shaped conductor 6 at the tip of the detection pen 2 are near the surface of the tablet 1,
.. of the tablet 1 are capacitively coupled with a small capacitance. Therefore, an electric signal between the stylus conductor 5 and the ring-shaped conductor 6 at the tip of the detection pen 2 is transmitted to each electrode wire 7, 7, 7, ... Of the tablet 1 at a level according to the magnitude of the coupling capacitance. X direction and Y
Directional analog multiplexers 8 and 9 are each electrode line 7,
Two adjacent electrodes 7, 7, ... Are sequentially switched while forming a pair, and a balanced voltage signal between the two electrode lines is applied to the balanced-unbalanced converter 10.

【０００８】この平衡不平衡変換器１０の出力信号電圧
は取扱い易い対グランドレベルの不平衡信号に変換され
て、バンドパスフィルタ１１へ印加される。バンドパス
フィルタ１１は正弦波の基本波成分のみ通過させ、各高
調波を阻止し、信号伝達経路の途中で混入した外乱信号
を減衰させる。バンドパスフィルタ１１の出力信号は信
号検出及び制御部１２へ印加される。The output signal voltage of the balance-unbalance converter 10 is converted into an unbalanced signal with respect to ground level which is easy to handle, and is applied to the bandpass filter 11. The bandpass filter 11 passes only the fundamental wave component of the sine wave, blocks each harmonic, and attenuates the disturbance signal mixed in the middle of the signal transmission path. The output signal of the bandpass filter 11 is applied to the signal detection and control unit 12.

【０００９】この信号伝達手段の特徴は本願出願人の出
願になる特願平５−１２３６０１号に記載したが、本質
的に外乱の影響を受けない信号伝達手段である。Ｘ方向
及びＹ方向にそれぞれ平行な複数の電極線を持つタブレ
ットと、信号発生器を内蔵しその平衡出力をペン先端部
の二つの導体へ接続されたケーブル無しの検出ペンと、
隣接電極線からの信号を平衡不平衡変換することによる
レベル検出部とで主に構成され近似三角形を成すレベル
検出特性を持つ。The characteristics of this signal transmitting means are described in Japanese Patent Application No. 5-123601 filed by the applicant of the present application, but the signal transmitting means is essentially unaffected by disturbance. A tablet having a plurality of electrode lines parallel to the X direction and the Y direction, and a detection pen without a cable in which a signal generator is incorporated and its balanced output is connected to two conductors at the tip of the pen,
It has a level detection characteristic which is mainly composed of a level detection section by performing balanced-unbalanced conversion of signals from adjacent electrode lines and which forms an approximate triangle.

【００１０】次に信号検出及び制御部１２において行わ
れる、本発明の特徴である信号レベルによる座標判定に
ついて説明する。信号の位相を無視した絶対値による検
出レベルと、検出ペン２の先端部スタイラス導体５のタ
ブレット１のＸ軸上位置（Ｙ軸上位置に対しても同様）
に関する特性曲線は図２に示すが、選択された二電極線
の中心点でディップした左右対称の二つ山のある特性で
ある。特性曲線２０はｎを任意番目の電極線７としてｎ
とｎ＋１番目の電極線７による信号検出レベル特性であ
り、特性曲線２１はｎ＋１とｎ＋２番目の電極線７によ
る特性であり、特性曲線２２はｎ＋２とｎ＋３番目の電
極線７による特性である。Next, the coordinate determination based on the signal level, which is a feature of the present invention, performed in the signal detection / control section 12 will be described. The detection level based on the absolute value ignoring the phase of the signal and the position on the X-axis of the tablet 1 of the tip stylus conductor 5 of the detection pen 2 (the same applies to the position on the Y-axis).
The characteristic curve regarding is shown in FIG. 2, and is a characteristic having two symmetrical peaks and dips at the center point of the selected two-electrode wire. The characteristic curve 20 has n as an arbitrary electrode line 7
And the signal detection level characteristic by the (n + 1) th electrode line 7, the characteristic curve 21 is a characteristic by the n + 1 and n + 2th electrode line 7, and the characteristic curve 22 is a characteristic by the n + 2 and n + 3rd electrode line 7.

【００１１】これらの信号検出特性曲線により、信号検
出レベルの大きさの順位で上位２〜３番目までのものか
ら、検出ペン２の先端部スタイラス導体５がどの電極線
間のそのまたどちらの半区間内にあるかを判別できる事
は自明である。その半区間内のどの位置にあるかを、補
間法で求める。According to these signal detection characteristic curves, from the top two to the third in the order of magnitude of the signal detection level, the tip stylus conductor 5 of the detection pen 2 is located between which electrode lines and which half of the electrode line. It is obvious that it is possible to determine whether or not it is within the section. The position in the half section is obtained by the interpolation method.

【００１２】近似補間量を先ず求めるため図３に示す直
線近似特性で考える。折れ線グラフ３０はｎとｎ＋１番
目の電極線７による信号検出レベルの近似グラフであ
り、折れ線グラフ３１はｎ＋１とｎ＋２番目の電極線７
による信号検出レベルの近似グラフであり、折れ線グラ
フ３２はｎ＋２とｎ＋３番目の電極線７による信号検出
レベルの近似グラフである。今、検出ペン２の先端部ス
タイラス導体５が図３のタブレット１のＸ軸上に示す位
置にあったとすると、三角形ＡＢＣ（及び三角形ＡＤ
Ｅ）に着目し、近似補間量をＸとして、 Ｘ＝（ｄ／２）×２．５（Ｓ23−Ｓ01）／（Ｓ23＋Ｓ01）・・・式１ である。但し ｄ＝隣接電極線の間隔 Ｓ01＝ｎとｎ＋１番目の電極線による信号検出レベル Ｓ23＝ｎ＋２とｎ＋３番目の電極線による信号検出レベ
ル であり係数２．５は実測により得た平均値である。この
近似値を更に電極線７と検出ペン２の先端部の二つの導
体５及び６との物理的各寸法により決まる補正特性によ
り補正して正確な補間量が求まる。また、検出ペン２の
先端部スタイラス導体５の位置が電極線間の左側半区間
にある場合は、補間量を電極線間の中間点から左方向
（負方向）とする。 Ｙ軸についても全く同様の方法で
精度良く位置座標を求める事が出来る。 信号検出及び
制御部１２は上記の線間補間を行いＸ及びＹ座標を決定
してデジタル出力する。First, the linear interpolation characteristic shown in FIG. 3 is used to obtain the approximate interpolation amount. A line graph 30 is an approximate graph of the signal detection level by the n and n + 1th electrode lines 7, and a line graph 31 is an n + 1 and n + 2th electrode line 7.
Is an approximate graph of the signal detection level according to the above, and the line graph 32 is an approximate graph of the signal detection level due to the (n + 2) th and (n + 3) th electrode lines 7. Now, assuming that the tip stylus conductor 5 of the detection pen 2 is located at the position shown on the X axis of the tablet 1 in FIG. 3, the triangle ABC (and the triangle AD
Focusing on E), assuming that the approximate interpolation amount is X, X = (d / 2) × 2.5 (S23−S01) / (S23 + S01) ... Equation 1 However, d = interval between adjacent electrode lines S01 = n and signal detection level by n + 1th electrode line S23 = n + 2 and signal detection level by n + 3rd electrode line and coefficient 2.5 is an average value obtained by actual measurement. This approximate value is further corrected by a correction characteristic determined by the physical dimensions of the electrode wire 7 and the two conductors 5 and 6 at the tip of the detection pen 2 to obtain an accurate interpolation amount. When the position of the tip stylus conductor 5 of the detection pen 2 is in the left half section between the electrode lines, the interpolation amount is leftward (negative direction) from the midpoint between the electrode lines. With respect to the Y axis, the position coordinates can be accurately obtained by the same method. The signal detection and control unit 12 performs the above-described interline interpolation to determine the X and Y coordinates and digitally outputs them.

【００１３】尚、従来方式により求めた補間量と本方式
により求めた補間量とを併用し、二者の平均を取るこ
と、または重み付け平均を取ること、更には区間分けし
て従来方式と本方式による補間量を使い分ける、等の方
法もあることは言うまでもない。It should be noted that the interpolation amount obtained by the conventional method and the interpolation amount obtained by the present method are used together to obtain the average of the two or take the weighted average, and further divide the interval into the conventional method and the original method. It goes without saying that there is also a method of properly using the interpolation amount according to the method.

【００１４】[0014]

【発明の効果】 以上説明したように本方式の補間法で
は、特性曲線のうち直線性の良い部分を使用しているた
め、近似値そのものが、さらなる補正の必要がない位に
実際の位置座標に近く、また電極線の中間点の検出座標
の連続性も良く信頼度の高い座標出力結果が得られた。As described above, in the interpolation method of the present method, since the portion of the characteristic curve having a good linearity is used, the approximate value itself does not need to be corrected, and the actual position coordinate does not need to be corrected. In addition, the detected coordinates at the midpoint of the electrode line are continuous and a highly reliable coordinate output result was obtained.

【図面の簡単な説明】[Brief description of drawings]

【図１】 本補間法を使用する装置の構成図を兼ねた電
気信号系統図FIG. 1 is an electrical signal system diagram that also serves as a block diagram of a device that uses this interpolation method.

【図２】 信号検出レベル特性図FIG. 2 Signal detection level characteristic diagram

【図３】 補間計算用折れ線近似検出レベル図FIG. 3 is a polygonal line approximation detection level diagram for interpolation calculation.

【符号の説明】[Explanation of symbols]

１ タブレット ２ 検出ペン ３ 正弦波信号発生器 ４ 電池 ５ 検出ペン先端部のスタイラス導体 ６ 検出ペン先端部のリング状導体 ７ 電極線 ８ Ｘ方向アナログマルチプレクサ ９ Ｙ方向アナログマルチプレクサ １０ 平衡不平衡変換器 １１ バンドパスフィルタ １２ 信号検出及び制御部 ２０ ｎとｎ＋１番目の電極線による信号検出レベル特
性 ２１ ｎ＋１とｎ＋２番目の電極線による信号検出レベ
ル特性 ２２ ｎ＋２とｎ＋３番目の電極線による信号検出レベ
ル特性 ３０ ｎとｎ＋１番目の電極線に対する折れ線近似特性 ３１ ｎ＋１とｎ＋２番目の電極線に対する折れ線近似
特性 ３２ ｎ＋２とｎ＋３番目の電極線に対する折れ線近似
特性1 tablet 2 detection pen 3 sine wave signal generator 4 battery 5 stylus conductor at the tip of the detection pen 6 ring conductor at the tip of the detection pen 7 electrode wire 8 X-direction analog multiplexer 9 Y-direction analog multiplexer 10 balanced-unbalanced converter 11 Band-pass filter 12 Signal detection and control unit 20 Signal detection level characteristic by n and n + 1th electrode line 21 n + 1 and n + Signal detection level characteristic by second electrode line 22 Signal detection level characteristic by n + 2 and n + 3rd electrode line 30 n And n + 1 line electrode approximation characteristics for the electrode line 31 n + 1 and n + line polygon approximation characteristics for the second electrode line 32 n + 2 and n + line approximation characteristics for the third electrode line

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 Ｘ及びＹ座標軸に沿って配設された複数
の電極線を有するタブレットと、該タブレットの電極線
とそれぞれ静電容量結合する二つの導体を先端部に配置
した検出ペンと、前記電極線の隣合う二本からの信号を
平衡入力し順次切り換え接続し二線平衡信号出力するア
ナログマルチプレクサと、該アナログマルチプレクサか
らの平衡信号を不平衡信号に変換する平衡不平衡変換器
と、該平衡不平衡変換器からの不平衡信号を印加される
バンドパスフィルタと、該バンドパスフィルタを介して
信号を印加される信号検出及び制御部とを有し、前記検
出ペン内部に電源部と検出ペン先端部の二つの導体へ平
衡接続された正弦波、矩形波等の交番信号発生器等が配
置され、前記電極線の隣接電極線毎の平衡信号電圧レベ
ルを計測することによって、タブレットへの検出ペンの
当接位置座標を出力する座標検出装置において、検出信
号レベルから電極線間の位置を補間するにあたり、 Ｘ＝（ｄ／２）×２．５（Ｓ23−Ｓ01）／（Ｓ23＋Ｓ01）・・・式１ の式１により得られた近似補間量Ｘを用い、または更に
この近似値を前記電極線と前記検出ペン先端部の二つの
導体との物理的各寸法により決まる補正特性とを用いる
事による、前記タブレットへの前記検出ペンの電極線間
当接位置座標を詳細に決定するための補間方法。但し、 ｄ＝電極線間隔 Ｓ01＝ｎを任意番目の電極線としたときのｎとｎ＋１番
目の電極線による信号検出レベル Ｓ23＝ｎ＋２とｎ＋３番目の電極線による信号検出レベ
ルである。1. A tablet having a plurality of electrode lines arranged along the X and Y coordinate axes, and a detection pen having at its tip a two conductors respectively capacitively coupled to the electrode lines of the tablet. An analog multiplexer that inputs signals from two adjacent electrode lines in a balanced manner and sequentially switches and connects them to output a two-wire balanced signal; and a balanced-unbalanced converter that converts a balanced signal from the analog multiplexer into an unbalanced signal, It has a bandpass filter to which an unbalanced signal from the balance-unbalance converter is applied, and a signal detection and control unit to which a signal is applied via the bandpass filter, and a power supply unit inside the detection pen. An alternating signal generator, such as a sine wave or a rectangular wave, which is balanced-connected to the two conductors at the tip of the detection pen, is arranged to measure the balanced signal voltage level for each electrode line adjacent to the electrode line. Therefore, in the coordinate detection device that outputs the contact position coordinates of the detection pen on the tablet, when interpolating the position between the electrode lines from the detection signal level, X = (d / 2) × 2.5 (S23−S01) / (S23 + S01) ... Using the approximate interpolation amount X obtained by the equation 1 of the equation 1, or further, the approximate value is determined by the physical dimensions of the electrode wire and the two conductors of the detection pen tip. An interpolation method for determining in detail the contact position coordinates between the electrode lines of the detection pen on the tablet by using a correction characteristic. However, d = interval between electrode lines S01 = signal detection level by the nth and n + 1th electrode lines when S01 = n is an arbitrary electrode line S23 = n + 2 and a signal detection level by the n + 3rd electrode line