Sprintray Inc v. Shining 3D Technology Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Sprintray, Inc. (California)
  • Defendant: SHINING 3D TECH CO., LTD. (China) and Shining 3D Technology, Inc. (California)
  • Plaintiff's Counsel: Herbert Smith Freehills Kramer (US) LLP
• Case Identification: 4:26-cv-06026, N.D. Cal., 06/18/2026
• Venue Allegations: Venue is alleged to be proper because Defendant Shining 3D Technology, Inc. resides in the district, and Defendant Shining 3D Tech Co., Ltd. is a foreign entity, for which venue is proper in any judicial district.
• Core Dispute: Plaintiff alleges that Defendant's AccuFab-F1 and AccuFab-CEL 3D printers, along with their associated resin tanks, infringe five patents related to resin solidification substrates and assemblies for stereolithography 3D printing.
• Technical Context: The lawsuit concerns stereolithography (SLA) 3D printing technology, specifically assemblies within resin-based printers used in the dental industry to reduce separation forces and improve print quality.
• Key Procedural History: The complaint alleges that Plaintiff complies with the patent marking statute by providing notice of its patents on its website, which may be relevant to pre-suit knowledge for claims of willful infringement.

Case Timeline

Date	Event
2009-10-19	Earliest Priority Date for '355 and '910 Patents
2019-02-21	Earliest Priority Date for '555, '588, and '180 Patents
2021-01-19	U.S. Patent No. 10,894,355 Issued
2023-04-25	U.S. Patent No. 11,633,910 Issued
2023-06-20	U.S. Patent No. 11,679,555 Issued
2024-02-01	AccuFab-CEL 3D Printer Launched (approx.)
2025-01-01	AccuFab-F1 3D Printer Launched (approx.)
2026-03-17	U.S. Patent No. 12,576,588 Issued
2026-03-24	U.S. Patent No. 12,583,180 Issued
2026-06-18	Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 10,894,355 - "Resin Solidification Substrate and Assembly"

• Patent Identification: U.S. Patent No. 10,894,355, "Resin Solidification Substrate and Assembly," issued January 19, 2021 (the "'355 Patent").

The Invention Explained

• Problem Addressed: The patent addresses the difficulty in stereolithography (SLA) 3D printing of reliably separating a newly solidified layer of resin from the underlying substrate without causing print failures, damage to the object, or excessive "peel forces" '355 Patent, col. 1:50-65 Compl. ¶14
• The Patented Solution: The invention proposes a multi-layer assembly comprising two main components: a "solidification substrate assembly" (containing a rigid or semi-rigid translucent substrate in a frame) and a separate "film assembly" (containing a film in its own frame) '355 Patent, col. 9:21-30 '355 Patent, abstract The complaint alleges these assemblies are connected and work together to reduce separation forces during the printing process Compl. ¶14 Compl. ¶47
• Technical Importance: This layered approach is designed to improve print reliability and success rates in bottom-up SLA printing by managing the strong adhesion forces that occur between newly cured resin and the print window '355 Patent, col. 10:55-64

Key Claims at a Glance

• The complaint asserts at least Claim 1 Compl. ¶44
• The essential elements of independent Claim 1 are:
  • A multi-layer assembly for making a three-dimensional object by solidifying a solidifiable material, comprising:
  • a rigid or semi-rigid solidification substrate assembly comprising a frame and a rigid or semi-rigid translucent solidification substrate disposed in the frame;
  • a film assembly, wherein the rigid or semi-rigid solidification substrate assembly is connected to the film assembly, and the film assembly includes at least one frame and a film disposed in the at least one frame.
• The complaint does not explicitly reserve the right to assert dependent claims but makes allegations against "one or more claims" of the patent Compl. ¶43

U.S. Patent No. 11,633,910 - "Resin Solidification Substrate and Assembly"

• Patent Identification: U.S. Patent No. 11,633,910, "Resin Solidification Substrate and Assembly," issued April 25, 2023 (the "'910 Patent").

The Invention Explained

• Problem Addressed: Like the '355 Patent, this patent aims to solve the problem of high adhesion forces between a newly formed object layer and the solidification substrate, which can damage the printed object during separation Compl. ¶17 '910 Patent, col. 1:52-65
• The Patented Solution: The patent describes a multi-layer system where the first surface of a film assembly is "adjacent to and in non-adhesive contact with" the first surface of the solidification substrate '910 Patent, claim 1 Compl. ¶65 This non-adhesive interface is the key feature intended to facilitate easier separation of the printed layers '910 Patent, abstract
• Technical Importance: By creating a non-adhesive interface at the solidification plane, the invention seeks to mitigate adhesion forces, thereby improving print reliability and preventing damage to the object during the peeling process Compl. ¶17

Key Claims at a Glance

• The complaint asserts at least Claim 1 Compl. ¶65
• The essential elements of independent Claim 1 are:
  • A multi-layer system for making a three-dimensional object by solidifying a solidifiable material, comprising:
  • a rigid or semi-rigid solidification substrate assembly comprising a frame and a rigid or semi-rigid translucent solidification substrate disposed in the frame, wherein the substrate comprises a first surface and a second surface opposite the first surface;
  • a film assembly including at least one film frame and at least one film disposed in the at least one film frame, wherein the at least one film comprises a first surface and a second surface opposite the first surface of the at least one film;
  • wherein the first surface of the at least one film is adjacent to and in non-adhesive contact with the first surface of the rigid or semi-rigid translucent solidification substrate.
• The complaint alleges infringement of "one or more claims" Compl. ¶64

Multi-Patent Capsule: U.S. Patent No. 11,679,555

• Patent Identification: U.S. Patent No. 11,679,555, "Reservoir with Substrate and Assembly for Reducing Separation Forces in Three-Dimensional Printing," issued June 20, 2023 (the "'555 Patent").
• Technology Synopsis: The patent addresses reducing separation forces in bottom-up 3D printing Compl. ¶20 It claims a substrate assembly including a first layer with a permeable film to hold the resin, a second layer below it, and a third layer comprising a "permeable substrate" disposed between the first and second layers, which is alleged to reduce separation forces and improve print reliability Compl. ¶20 Compl. ¶89
• Asserted Claims: The complaint asserts at least Claim 1 Compl. ¶89
• Accused Features: The complaint alleges that the layered structure of the Accused Products' resin tanks, particularly the HyperClear tank's lower scattering film, constitutes the claimed "third layer comprising a permeable substrate" Compl. ¶¶90-93

Multi-Patent Capsule: U.S. Patent No. 12,576,588

• Patent Identification: U.S. Patent No. 12,576,588, "Reservoir with Substrate Assembly for Reducing Separation Forces in Three-Dimensional Printing," issued March 17, 2026 (the "'588 Patent").
• Technology Synopsis: The patent claims a substrate assembly for a 3D printer reservoir that includes a first film layer, a second layer below it, and a "third layer comprising a semi-transparent substrate" Compl. ¶109 This third layer is adapted to "enhance a surface finish of a 3D-printed object" held between the first and second layers Compl. ¶109
• Asserted Claims: The complaint asserts at least Claim 1 Compl. ¶109
• Accused Features: The complaint alleges that the "scattering film" used in the Accused Products' HyperClear resin trays functions as the claimed "third, semi-transparent layer" configured to diffuse light and enhance surface finish Compl. ¶¶113, 134

Multi-Patent Capsule: U.S. Patent No. 12,583,180

• Patent Identification: U.S. Patent No. 12,583,180, "Reservoir Assembly for Enhancing a Surface Finish of a 3D-Printed Object," issued March 24, 2026 (the "'180 Patent").
• Technology Synopsis: This patent is similar to the '588 Patent, claiming a reservoir assembly with a first film layer, a second layer, and a "third layer comprising a semi-transparent substrate" Compl. ¶130 This third layer is intended to enhance the surface finish of a printed object held "without an adhesive" between the first and second layers Compl. ¶130 The complaint alleges this configuration diffuses light to reduce pixelation and improve finish quality Compl. ¶26
• Asserted Claims: The complaint asserts at least Claim 1 Compl. ¶130
• Accused Features: The complaint again points to the "diffusing film" in the HyperClear resin trays as the infringing "third layer," alleging it enhances surface finish as claimed Compl. ¶134

III. The Accused Instrumentality

Product Identification

• The accused instrumentalities are the Shining 3D AccuFab-F1 and AccuFab-CEL 3D printers, sold together with their associated "HyperClear" and "Standard" resin tanks and related accessories (collectively, the "Accused Products") Compl. ¶38

Functionality and Market Context

• The AccuFab-F1 is described as a high-precision Digital Light Processing (DLP) 3D printer, while the AccuFab-CEL is described as a high-accuracy Liquid Crystal Display (LCD) 3D printer Compl. ¶¶30-31 Compl. ¶¶33-34 Both are resin-based additive manufacturing systems that build 3D objects layer-by-layer from a liquid photopolymer resin Compl. ¶¶31, 34
• The complaint alleges both printers are designed for the dental market and are offered for sale in the United States Compl. ¶¶29, 32, 33 The core of the infringement allegations centers on the multi-layer construction of the printers' build area, which includes a light source, a transparent substrate assembly (e.g., glass plate and screen protector), and a removable resin tank assembly that contains one or more films Compl. ¶45 Compl. ¶46 Compl. ¶47 A marketing screenshot shows the AccuFab F1 with its support frame and the translucent glass plate that forms part of the substrate assembly Compl. p. 26
• The complaint emphasizes that the printers are sold with and are allegedly inoperable without the accused Standard or HyperClear resin tanks, which hold the liquid photopolymer Compl. ¶36 Compl. ¶37 The HyperClear resin tank is specifically marketed as enhancing the surface finish of printed objects Compl. p. 79 Compl. p. 92

IV. Analysis of Infringement Allegations

10,894,355 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A multi-layer assembly for making a three-dimensional object by solidifying a solidifiable material, comprising:	The Accused Products (F1 and CEL printers with their resin trays) are alleged to be multi-layer assemblies that make 3D objects from resin.	¶45	col. 11:15-20
a rigid or semi-rigid solidification substrate assembly comprising a frame and a rigid or semi-rigid translucent solidification substrate disposed in the frame;	The Accused Products allegedly include a "support frame mounted to the base of the printer, on which a rigid or semi-rigid translucent substrate (i.e., a glass plate) is positioned and secured." An annotated image identifies these components.	¶45; ¶46	col. 9:21-30
a film assembly, wherein the rigid or semi-rigid solidification substrate assembly is connected to the film assembly, and the film assembly includes at least one frame and a film disposed in the at least one frame.	The Accused Products allegedly include a resin tank (the "film assembly") with a frame and a tensioned film. This film assembly is allegedly "connected to the substrate assembly through the support frame" to form the solidification interface.	¶46; ¶47	col. 13:21-30

• Identified Points of Contention:
  • Scope Questions: A potential dispute may arise over the term "connected." The complaint alleges the film assembly is "connected to the substrate assembly through the support frame" Compl. ¶47 A court may need to determine if this indirect structural relationship, where both assemblies are attached to a common printer frame, satisfies the claim requirement that the "substrate assembly is connected to the film assembly."

11,633,910 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A multi-layer system for making a three-dimensional object by solidifying a solidifiable material, comprising:	The Accused Products are alleged to be multi-layer systems for making 3D objects from resin.	¶66	col. 11:15-20
a rigid or semi-rigid solidification substrate assembly comprising a frame and a rigid or semi-rigid translucent solidification substrate disposed in the frame, wherein the rigid or semi-rigid translucent solidification substrate comprises a first surface and a second surface opposite the first surface;	The complaint alleges this substrate is the printer's glass plate and its protective film/screen protector. The "first surface" is identified as the top of the screen protector, and the "second surface" is the glass surface underneath it.	¶66; ¶67	col. 9:21-30
a film assembly including at least one film frame and at least one film disposed in the at least one film frame, wherein the at least one film comprises a first surface and a second surface opposite the first surface of the at least one film,	The complaint identifies the resin tank as the "film assembly," which includes a frame and at least one film (e.g., a permeable release film). The film's bottom surface is the "first surface" and its top surface is the "second surface."	¶68; ¶69	col. 9:31-41
wherein the first surface of the at least one film is adjacent to and in non-adhesive contact with the first surface of the rigid or semi-rigid translucent solidification substrate.	The complaint alleges the bottom of the film in the resin tank rests in "non-adhesive contact" with the "screen protective film/screen protector" on the printer base. The complaint provides a demonstrative illustration mapping these alleged layers and the non-adhesive contact point.	¶69; ¶70	col. 9:42-49

• Identified Points of Contention:
  • Scope Questions: The infringement theory hinges on construing the "rigid or semi-rigid translucent solidification substrate" to include the printer's own built-in glass plate and screen protector Compl. ¶67 A court will have to decide whether a component of the printer base can be considered part of the claimed disposable/interchangeable "substrate assembly."
  • Technical Questions: A key question will be whether the interface between the bottom film of the resin tank and the printer's screen protector factually constitutes "non-adhesive contact" as required by the claim and described in the patent. The complaint's demonstrative diagram explicitly illustrates this theory of non-adhesive contact between the "scattering film bottom" and the "screen protective film" Compl. p. 47

V. Key Claim Terms for Construction

Term: "rigid or semi-rigid translucent solidification substrate" ('910 Patent, Claim 1)

• Context and Importance: The plaintiff's infringement theory for the '910 Patent requires that this claimed "substrate" be interpreted to include components of the main printer body itself-specifically, the glass plate and its overlying screen protector Compl. ¶67 Practitioners may focus on this term because its definition is central to determining whether a part of the printer can be combined with the disposable resin tank to meet the claim limitations.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification describes the substrate as providing a "substantially planar surface" for solidification, a function which the printer's glass plate and screen protector also perform '910 Patent, col. 9:50-53
  • Evidence for a Narrower Interpretation: The patent figures, such as Figure 1A, depict the "solidification substrate" (79) as a distinct component within a larger assembly, separate from the main body of the printer that contains the light source '910 Patent, Fig. 1A The patent repeatedly describes the "solidification substrate assembly" as a component, suggesting it is a discrete, integrated unit rather than a collection of parts from both a disposable tank and the printer chassis.

Term: "connected" ('355 Patent, Claim 1)

• Context and Importance: Infringement of the '355 Patent requires that the "solidification substrate assembly" is "connected to the film assembly." The complaint alleges this connection occurs "through the support frame" of the printer, not directly between the two assemblies Compl. ¶47 The viability of this infringement theory depends on whether such an indirect structural linkage satisfies the claim's "connected" requirement.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification may describe the claimed assemblies in the context of their operational relationship within a larger system, which could support an argument that being "connected" includes being functionally linked through a common frame.
  • Evidence for a Narrower Interpretation: The patent's detailed description and figures illustrate various mechanical linkage and peeling mechanisms where components are directly attached (e.g.,'355 Patent, Figs. 11-17). This may suggest that "connected" implies a direct physical attachment between the two claimed assemblies, rather than a more remote connection via the printer's main chassis.

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced infringement, stating that Defendants instruct and encourage infringement through user manuals, instructional videos, marketing materials, and customer support Compl. ¶¶55-56 Compl. ¶¶79-80 Contributory infringement is also alleged, based on the sale of the Accused Products' resin tanks, which are claimed to be a material part of the invention, not suitable for substantial non-infringing use, and specifically designed for use in the infringing printers Compl. ¶¶57-58 Compl. ¶¶81-82
• Willful Infringement: Willfulness is alleged based on knowledge of the Asserted Patents. The complaint pleads two bases for this knowledge: first, constructively from Plaintiff's patent marking website Compl. ¶41, and second, actual knowledge acquired "at the very least" upon service of the complaint Compl. ¶41 Compl. ¶51

VII. Analyst's Conclusion: Key Questions for the Case

• A core issue will be one of definitional scope: Can the term "rigid or semi-rigid translucent solidification substrate assembly," as described in the context of a self-contained unit in the '910 Patent, be construed to encompass a combination of a disposable film assembly and a permanent screen protector on the main body of the printer, as Plaintiff alleges?
• A second central question will be one of claim construction and connection: For the '355 Patent, does the term "connected," in the context of the patent's detailed mechanical embodiments, read on an indirect structural relationship where two separate assemblies are mounted to a common printer chassis, or does it require a direct physical linkage between the assemblies themselves?
• A key evidentiary question will be one of technical function: For the patents claiming a functional enhancement ('555, '588, '180), what evidence beyond marketing materials (e.g.,Compl. p. 79) will be presented to prove that the accused "HyperClear" system's layered structure performs the specific claimed functions of reducing separation forces or enhancing surface finish through light diffusion in the manner described by the patents?