PTAB

IPR2017-01258

formLabs Inc v. EnVisionTec Inc

Log In
Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Apparatus for the Production of a Three-Dimensional Object
  • Brief Description: The ’472 patent relates to a constrained-surface stereolithography apparatus for 3D printing. The invention addresses the problem of a newly-formed photopolymer layer adhering to the build surface by using a flexible, "gel-like elastic" separating layer arranged between the transparent reference plane and the material layer, allowing the object to be separated without damage.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 9-12 and 15 by Akamine

  • Prior Art Relied Upon: Akamine (Japanese Patent Application Publication No. H11-348135).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Akamine discloses every limitation of independent claim 9 and dependent claims 10-12 and 15. Akamine describes a constrained-surface stereolithography device where a transparent plate (4) serves as the claimed "flat plane." To solve the known problem of adhesion, Akamine applies an "elastically deformable high polymer material" (7), such as silicone, directly onto the plate. This material functions as the claimed "flexible, elastic separating layer" arranged between the plane and the hardened resin layer (10). Akamine explicitly teaches that this layer deforms elastically and peels away from the hardened resin, ensuring the layer remains attached to the plane while allowing the object to be separated, thus meeting the adhesion requirements of claim 10 and the structural arrangement of claim 11. Akamine’s resin tank (2) with lateral walls forms the "holding basin" of claim 12, and the transparency of both the plate and separating layer, as required for the device to function, anticipates claim 15.

Ground 2: Anticipation of Claims 9-12 and 15 by Gotoh

  • Prior Art Relied Upon: Gotoh (Japanese Patent Application Publication No. 1994-81727).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Gotoh, like Akamine, independently anticipates the challenged claims. Gotoh discloses an optical molding device using a "pull-up method" (constrained-surface stereolithography). The device’s clear glass bottom surface (1a) of the resin tank is the claimed "flat plane." Gotoh bonds a "separation promotion thin film member" (8) directly to this surface, which is the claimed "flexible, elastic separating layer." This thin film is described as exhibiting "elastic deformation" to promote smooth separation from the cured product layer (7), thereby anticipating the core limitations of claim 9. Petitioner contended that Gotoh’s disclosure of the film remaining attached to the plane while peeling from the product layer inherently teaches the adhesion relationship of claim 10. The device's glass container (1) is the "holding basin" of claim 12, and Gotoh explicitly teaches that both the glass plate and the separating layer are transparent (at least 90% light transmissivity), anticipating claim 15.

Ground 3: Claims 10 and 14 are obvious over Akamine in view of Mizukami and McDonald

  • Prior Art Relied Upon: Akamine, Mizukami ("An Integrated Micro-Electrophoretic Chip Fabricated Using a New Stereolithographic Process," IEEE MEMS-2000), and McDonald ("Fabrication of microfluidic systems in poly(dimethylsiloxane)," Electrophoresis, Jan. 2000).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground argued that even if Akamine does not explicitly disclose the "greater by a multiple" adhesion limitation of claim 10, it would have been obvious to a Person of Ordinary Skill in the Art (POSA) to achieve it. Akamine provides the base stereolithography system. Mizukami provides measured data for the adhesion strength between a silicone coating and a hardened acrylic resin, quantifying it as approximately 1.85×10⁴ N/m². McDonald teaches a method for irreversibly sealing polydimethylsiloxane (PDMS), a common silicone, to glass with an adhesion strength that can withstand 30-50 psi. Petitioner calculated this to be equivalent to 20.6×10⁴ to 34.5×10⁴ N/m².
    • Motivation to Combine: A POSA seeking to create a durable and reliable separating layer in Akamine’s device would combine these teachings. The POSA would use McDonald’s technique to ensure a strong, permanent bond between Akamine's silicone layer and its glass plate. Simultaneously, the POSA would know from Mizukami the expected low adhesion between that same silicone and the hardened resin. This combination would result in an adhesion to the plane that is 11 to 18 times greater than the adhesion to the hardened material, rendering the "greater by a multiple" limitation obvious.
    • Expectation of Success: A POSA would have a high expectation of success, as optimizing adhesion for release coatings was a known design parameter, and the references used common materials (silicone, glass, acrylic resin) in the same technical field.

  • Additional Grounds: Petitioner asserted numerous additional obviousness challenges, including grounds that claims 10 and 14 are obvious over Gotoh (Ground 7) and Mizukami (Ground 11); that claim 14 (reciting an "exchangeable unit") is obvious over Akamine, Gotoh, or Mizukami in view of Vorgitch (Patent 5,182,715) or Hull (Patent 4,575,330), both of which teach using removable, exchangeable resin vats; and that claim 9 is obvious over Mizukami in view of Akamine.

4. Key Claim Construction Positions

  • "gel-like elastic material": Petitioner argued this term lacked a clear technical meaning to a POSA. Citing the patent owner's statements during prosecution, Petitioner proposed the term should be construed under the broadest reasonable interpretation to mean "a material that has the required elasticity for being deformable, yet the elasticity for recovering its original state after deformation."
  • "greater by a multiple": Petitioner argued this phrase should be interpreted to mean that the adhesion of the separating layer to the plane is greater than its adhesion to the hardened material by any multiplier (integer or non-integer) large enough to ensure the layer remains reliably adhered to the plane while peeling away from the hardened material during separation.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 9-15 of Patent 7,195,472 as unpatentable.