前言：
加拿大專利法中規定可專利的發明的前提是基於「Purposive Construction/有目的的解釋」，判斷是否是法定可專利標的（section 2 of the Patent Act）－除法定不可專利的議題外，要有物理存在或是呈現出物理性的效果，並且需要解決問題與解決問題的手段。並且這些議題常常是針對電腦實現的發明（即軟體專利）。
本篇討論加拿大專利性要件「purposive construction」最高法院案例 - 「Free World Trust v Électro Santé Inc., 2000 SCC 66」。
案件資訊：
上訴人/專利權人：Free World Trust
被告：Électro Santé Inc., Paul Demers and Noël Desjardins
系爭專利：CA1,113,156、CA1,150,361
判決日期：Dec. 15, 2000
爭議歷史：
爭議中的專利關於用低頻電磁波照射人體不同部位的裝置，其中技術特點是透過「circuit means/電路手段」控制電磁波的振幅和頻率的方法，侵權被告販售實現相似治療目的的裝置，但有點不同的是被告侵權物是以微控制器執行相似治療方法，經侵權訴訟審理後，下級法院法官判定系爭專利不具新穎性因此無效，但上訴法院（Quebec Court of Appeal）推翻下級法院判決，表示專利有效，但是侵權不成立。
列舉'156案claim 1：
1. An electro-magnetic low frequency therapeutic system comprising a magnetization coil, said magnetization coil being stationary during a magnetic field treatment, for creating a preselected therapeutic magnetic field in response to preselected coil energizing-current waveforms whereby said magnetic field has desired treatment characteristics, said magnetic field having an adjustable intensity set by adjustable control means, said control means also having:
(i) circuit means for controlling the peak amplitude of the said magnetic field for achieving a specific modulation of said peak amplitude in a given time;
(ii) means to select the orientation and/or direction of the therapeutic magnetic field with respect to a tissue to be treated;
(iii) circuit means to select the frequency of interruption of the coil energizing-current to obtain a selected one of different therapeutic magnetic field time patterns;
(iv) means to select a desired treatment time; automatic demagnetizing means responsive to a preselected demagnetizing time and mode for attenuating said field in a desired manner to terminate a magnetic field treatment.
案件進入加拿大最高法院。
首先，解釋專利範圍，其中，先判斷申請專利範圍中的重要元件（essential elements），包括：
1. a control to regulate the peak amplitude and frequency of interruption of the current which “energizes” the coil;
2. such control to be provided by “circuit means”.
接著，通過比對先前技術以判斷系爭專利的有效性，由於先前技術並為論述系爭案發明要解決的技術問題，並無法證明系爭案發明無效。
在侵權議題上，涉及字義侵權（literal infringement）與實質侵權（substantive infringement），法院採用的判斷原則包括（這裡將重點註記中文）：
(a) The Patent Act promotes adherence to the language of the claims.
(b) Adherence to the language of the claims in turn promotes both fairness and predictability.（解釋申請專利範圍中用語要兼具公平性和可預測性）
(c) The claim language must, however, be read in an informed and purposive way.
(d) The language of the claims thus construed defines the monopoly. There is no recourse to such vague notions as the “spirit of the invention” to expand it further.（不能模糊地擴張發明精神）
(e) The claims language will, on a purposive construction, show that some elements of the claimed invention are essential while others are non-essential. The identification of elements as essential or non-essential is made:（申請專利範圍用語，在其有目的的解釋下，辨識出重要與不重要的特徵）
(i) on the basis of the common knowledge of the worker skilled in the art to which the patent relates;
(ii) as of the date the patent is published;
(iii) having regard to whether or not it was obvious to the skilled reader at the time the patent was published that a variant of a particular element would not make a difference to the way in which the invention works; or
(iv) according to the intent of the inventor, expressed or inferred from the claims, that a particular element is essential irrespective of its practical effect;（要根據發明人意圖推論專利範圍）
(v) without, however, resort to extrinsic evidence of the inventor's intention.（解釋專利範圍不必訴諸外部證據）
(f) There is no infringement if an essential element is different or omitted. There may still be infringement, however, if non-essential elements are substituted or omitted.（重要：如果重要元件不同或被忽略，即侵權不成立；如果不重要元件被替代或被忽略，侵權仍成立，因此判定專利範圍中重要／不重要元件在解釋專利範圍階段是十分重要的步驟。）
（法院即針對上述各點提出審判與論述）
結論是，根據專利範圍解釋，其中重要特徵包括以＂circuit means/電路手段＂（重要元件之一）控制電磁療法（electro-magnetotherapy），申請專利範圍也沒有表示＂circuit means＂不重要，反之，這是系爭專利發明核心，且在系爭專利申請之時並沒有可以得到相同功能與相同結果的其他選擇。
如此，在侵權分析過程，被告侵權對象是否採用＂circuit means＂控制電磁療法成為侵權成立與否的主要判斷依據。
基於以上判斷過程，上訴法院（Quebec Court of Appeal）判定侵權不成立。
最高法院則判定，針對申請專利範圍中的＂circuit means＂的解釋係基於發明前後1981年相關技術水平。而被告Électro Santé Inc.的被告侵權對象則是使用＂microcontroller＂，即便執行與系爭專利發明相似或相同的功能，但是卻是不同的方式，判定"circuit means"與"microcontroller"為不同的科技，因此被告侵權對象並未被系爭專利範圍所讀入，判決侵權不成立。
回頭看用以公平地、可預測地解釋專利範圍採用"purposive construction/有目的的解釋"的原則，以此判斷專利範圍中的重要元件（essential elements），並在
"“Purposive construction” does away with a purely literal interpretation but disciplines the scope of the “substantive” claims construction in the interest of fairness to both the patentee and the public."（運用有目的的解釋是要排除純粹字面上的解釋，並限制實質專利範圍的擴大解釋，以在專利權人與公眾之間作出公平的解釋。）
my two cents:
看來，加拿大最高法院在發明人權益與公眾利益之間做了取捨，從＂spirit of invention＂來想，40年前circuit means（'156專利申請日在1979年，法院判斷基礎選擇在1981/1983年）是否涵蓋20年後的microcontroller（本案判決在2000年）？
... 我想當初使用circuit means用語就是想要涵蓋任何可執行相同功能的電路才是...～
加拿大專利局根據此案例的資訊（Patentable Subject-Matter under the Patent Act）：https://ised-isde.canada.ca/site/canadian-intellectual-property-office/en/patentable-subject-matter-under-patent-act
Ron
