Re Halliburton Energy Services Inc

The mental-act exclusion in section 1(2)(c) of the Patents Act 1977 has a narrow scope. It prevents claims from being performed by purely mental means. It does not extend to a computer-implemented method merely because the underlying algorithm could be performed mentally.

The Aerotel four-stage approach remains binding. A computer-implemented method of designing drill bits, using technical simulation and finite element analysis, is not excluded where its contribution is more than a computer program as such, a mathematical method or a mental act.

Halliburton appealed against two decisions of the Comptroller-General rejecting four patent applications concerning computer-implemented methods of designing roller cone drill bits. The applications were rejected as schemes, rules or methods for performing mental acts and as computer programs.

The appeals concerned whether the Comptroller had applied the mental-act exclusion too broadly, whether the claims were limited to computer implementation, and whether the Court of Appeal’s approach in Aerotel v Telco / Macrossan’s Application remained binding. The central issue was the proper scope of the mental-act exclusion and its application to the claimed drill-bit simulation method.

1. The appeals were allowed. The cases were remitted to the Comptroller.
2. The appeal was a review under CPR rule 52.11. Halliburton’s decision not to request a hearing before the Comptroller did not convert the appeal into a rehearing, and the procedure permitted evidence to be placed before the Comptroller.
3. The claim was properly construed as a computer-implemented method. The skilled reader would understand that the simulations were computer simulations and that outputting the results to a resource was a computer operation.
4. The correct scope of the mental-act exclusion was narrow. Its purpose was to ensure that patent claims could not be performed by purely mental means. It did not apply where the claim contained appropriate non-mental limitations. The claim therefore did not fall within the exclusion.
5. The four-stage approach in Aerotel v Telco / Macrossan’s Application remained the applicable domestic approach: construe the claim, identify the actual contribution, ask whether it fell solely within excluded subject matter, and check whether the contribution was technical.
6. The contribution was a computer-implemented method of designing drill bits using three-dimensional meshes, simulation of cutting-element interaction and calculation of forces. It was not solely a computer program, mathematical method or mental act. The specified data represented concrete drill-bit and drilling parameters, distinguishing the case from Gale.
7. Designing drill bits was a technical and industrial process. The use of finite element analysis addressed technical problems with technical solutions. The claimed invention therefore made a technical contribution and satisfied the patentability requirement.
8. The Comptroller’s Practice Note of 8 December 2008, insofar as it directed examiners to object to computerisation of what would otherwise be a pure mental act, adopted the wrong legal approach and should not be followed.
9. The wider submission that domestic law should depart from Aerotel in favour of the EPO approach did not arise. The Patents Court could not depart from binding Court of Appeal authority, and the statutory computer-program exclusion could not be interpreted out of existence.

• Comptroller-General of Patents: rejected the first three applications on 25 February 2011 (O/080/11) and the fourth application on 19 May 2011 (O/170/11).
• High Court (Patents Court): allowed the appeals and remitted the cases to the Comptroller.