Court Interprets Purported Contour Lines in Design Patent Drawings as Claimed Features

January 04, 2021

The benefits of clear surface shading in a design patent were highlighted in a recent district circuit decision, which found that purported contour or tangent edge lines added to the drawings to illustrate a transition edge between rounded and flat surfaces were not proper lines to indicate surface contour, but instead claimed features.

In order to show the contour or surface of 3D objects in 2D drawings, design applicants often use drawing techniques such as tangent edge lines, also referred to as wire framing, to indicate surface contours instead of or in addition to shading lines or stippling. The US District Court for the Northern District of California recently issued a claim construction order in simplehuman, LLC vs. iTouchless Housewares and Products Inc.,[1] construing the purported contour lines in two design patents to instead be claimed ornamental features.

simplehuman, LLC (simplehuman) brought a claim of patent infringement against iTouchless Housewares and Products, Inc. (iTouchless) asserting that iTouchless’s products infringe patents owned by simplehuman, including two design patents. Specifically, simplehuman alleges that iTouchless’s Dual-Deodorizer Oval Open-Top trash can product infringes US Design Patent No. D644,807 (the D’807 Patent) and iTouchless’s Dual-Compartment Open Top Trash and Recycle Can infringes US Design Patent No. D729,485 (the D’485 Patent) (collectively, the Asserted Design Patents)[2]. A comparison of iTouchless’s Deodorizer and the D’807 Patent, and iTouchless’s Recycle Can and the D’485 Patent are shown below.

Simplehuman trashcan

In response to simplehuman’s complaint, iTouchless filed a Motion to Dismiss arguing that the Asserted Design Patents were different from iTouchless’s products due, in part, to the Asserted Design Patents claiming seam lines that are not present in iTouchless’s products. simplehuman responded that the disputed lines that iTouchless was referring to were not seams at all, but instead contour lines indicating the surface contour, and thus the lines themselves are not part of the claimed design.

On December 14, 2020, the district court issued a Claim Construction Order construing whether the disputed lines of the Asserted Design Patents, annotated below, are claimed ornamental features or unclaimed contour lines.

Simpehuman trashcan

During claim construction, simplehuman argued that the disputed lines are shading or contour lines meant to demonstrate the shape of the trash cans. The district court looked to the illustrations of the Asserted Design Patents and stated that the disputed lines of the Asserted Design Patents “cannot possibly represent shading.”[3] For example, regarding the D’807 Patent, the district court stated that the disputed lines on the right side and top of the trash can do not indicate contour changes since the right side view and top view are largely flat, and thus devoid of any surface contours. The district court made a similar analysis for the D’485 Patent.

iTouchless argued that simplehuman did not include the disputed lines consistently on all surfaces. The district court agreed with iTouchless and further stated that, at most, the disputed lines “represent a delineation between rounded and flat surfaces” and the “shading urged by simplehuman...does not suffice to show contour because it doesn’t indicate which surface is receding...and includes lines in views where there would be no contour difference.[4]

Moreover, the district court was also convinced by iTouchless’s argument that the use of the disputed lines, shown as straight lines are undifferentiated compared to the boundary lines due to same line weight being used for both. The district court stated that this creates ambiguity since there is no ability to distinguish contour changes from ornamental surface features, and thus is inadequate under 37 C.F.R. § 1.152[5].

The Asserted Design Patents also originally included corresponding photographs which show shading where the drawings depict lines. During prosecution, the examiner cancelled the photographs via an amendment for improperly including photographs and line drawings in the same application. simplehuman argued that the photographs support that the disputed lines represent shading. However, the district court disagreed and found that the examiner excluded the photographs precisely because they contradicted the line drawings.

iTouchless also pointed out that simplehuman’s own unasserted patents, as well as the asserted utility patent in this very same case, use conventional shading practices. These conventional shading practices are published in a design patent application guide provided by the US Patent and Trademark Office (USPTO) to show common types of shading and do not include tangent edge lines.

Further, simplehuman presented a declaration from a former patent examiner who provided examples of other design patents that use the same drafting technique as the Asserted Design Patents, i.e., using straight unbroken lines to indicate contour. However, the district court stated that the technique is not helpful or sufficient to overcome the otherwise clear intrinsic evidence.

Accordingly, the district court adopted iTouchless’s proposed construction that the disputed lines are claimed seams and not proper contour lines.[6]

Practice Pointers

Many design patent applicants choose to use wire framing or tangent edge contour lines to illustrate surface contour, since such a technique is a well-accepted engineering drafting convention and can be easily added to drawings by computer aided design (CAD) software. However, as shown here, judges (who are not typically familiar with drawing techniques) may interpret the drawing differently than the applicant intended.

As a result, design patent applicants may want to consider avoiding the use of wire framing or tangent edge contour lines. While the hypothetical ordinary observer may be able to ascertain the shape of objects where tangent edge contour lines are used or if no stippling or shading is provided, it can be more difficult to do so. Also, while there is no requirement to include surface shading or contour lines at all, judges and factfinders may find it easier to appreciate features of the claimed design with more surface features shown. In addition to more accurately illustrating the surface contour, surface shading may also help the drawings generally look more realistic.

If contour lines are used, design applicants should be sure to use them consistently. Applicants should also consider differentiating contour lines from claimed lines. Using a lighter line weight than the claimed lines, including at least one break in each contour line, and/or consider including clarifying statements or disclaimers in the original specification as to what the lines represent can help that cause and make it clear what lines and features are claimed.


If you have any questions or would like more information on the issues discussed in this LawFlash, please contact the authors, John L. Hemmer (Philadelphia), Kenneth J. Davis (Philadelphia), or Vishal J. Parikh (Philadelphia), or any of the following lawyers:

Scott D. Sherwin
Jason C. White

Louis W. Beardell, Jr.

San Francisco
Brent A. Hawkins
Brett A. Lovejoy, Ph.D.

Silicon Valley
Dion M. Bregman
Michael J. Lyons

[1] Civil Action No. 4:19-cv-02701-HSG (N.D. Cal., December 14, 2020)

[2] simplehuman also alleged that iTouchless’s products infringe their utility patent, US Patent No. 6,626,316.

[3] See simplehuman, slip op at 4.

[4] See id, slip op at 7.

[5] 37 C.F.R. § 1.152 states that “[a]ppropriate and adequate surface shading should be used to show the character or contour of the surfaces represented.”

[6] The Claim Construction Order also included claim construction construing various terms from an asserted utility patent, US Patent No. 6,626,316, which is not addressed herein.