Source: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-cand-3_13-cv-05038/USCOURTS-cand-3_13-cv-05038-35/pdf.json

Nature of Suit Code: 830
Nature of Suit: Patent
Cause of Action: 35:145 Patent Infringement

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Case No.13-cv-05038 NC 

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United States District Court

Northern District of California

UNITED STATES DISTRICT COURT

NORTHERN DISTRICT OF CALIFORNIA

ENPLAS DISPLAY DEVICE 

CORPORATION, et al.,

Plaintiffs,

v.

SEOUL SEMICONDUCTOR 

COMPANY, LTD.,

Defendant.

Case No.13-cv-05038 NC 

ORDER FINDING CLAIM 2 OF ’554 

PATENT IS NOT INVALID

Plaintiff Enplas Display Device Corporation (“EDD”) asks this Court to find that 

claim 2 of the ’554 patent is invalid because it is an improper dependent claim. Dkt. No. 

457. Defendant Seoul Semiconductor Company disagrees. Dkt. No. 460. The Court held 

a jury trial in this case in March 2016. 

I. LEGAL STANDARD

Generally, a patent is presumed valid. 35 U.S.C. § 282. While this presumption 

can be rebutted, the party challenging validity must meet the “high burden” of proving 

invalidity by “clear and convincing evidence.” Sciele Pharma Inc. v. Lupin Ltd., 684 F.3d 

1253, 1260 (Fed. Cir. 2012). 35 U.S.C. § 112 provides, “a claim in dependent form shall 

contain a reference to a claim previously set forth and then specify a further limitation of 

the subject matter claimed.” “The statute stresses that a dependent claim must add a 

limitation to those recited in the independent claim.” Curtiss-Wright Flow Control Corp. 

v. Velan, Inc., 438 F.3d 1374, 1380 (Fed. Cir. 2006). 

Case 3:13-cv-05038-NC Document 467 Filed 04/08/16 Page 1 of 3
Case No.13-cv-05038 NC 2

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II. DISCUSSION

Claim 1 of the ’554 patent reads:

An illumination device, comprising:

a waveguide having an illumination coupler embedded in an 

interior region of said waveguide,

said illumination coupler adapted to receive light from a point 

source within said interior region, and to direct light between 

generally parallel top and bottom surfaces outside said interior 

region,

said illumination coupler comprising a refractive index 

interface which is inclined relative to at least one of said top 

and bottom surfaces

said interface being configured to reflect light rays emitted by 

the point source which propagate along a line that forms less 

than the critical angle of total internal reflection with respect to 

a line lying in one of said top and bottom surfaces,

such that light rays which would otherwise pass out of said 

waveguide are captured for propagation between said top and 

bottom surfaces.

Claim 2 of the ’554 patent reads:

The illumination device of claim 1, wherein said illumination 

coupler comprises a surface configured for total internal 

reflection of light incident therein.

At trial, Dr. Pollock testified briefly as to claim 2, as follows:

Q: And looking at Claim Number 2, what is added by that

dependency?

Pollock: Claim Number 2, let me just read it. It says: (reading)

“The elimination device of Claim 1,” so it’s a dependent claim,

“wherein said illumination coupler comprises a surface 

configured for total internal reflection of light incident 

thereon.”

In my opinion, it’s redundant. I don’t know what it adds.

Q: Does it add anything in your view?

Pollock: Not in my view. I’m not a lawyer, so -- but I don’t see

the point of that one.

Q: From a technical perspective, does it add anything?

Pollock: No change.

Case 3:13-cv-05038-NC Document 467 Filed 04/08/16 Page 2 of 3
Case No.13-cv-05038 NC 3

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Tr. 992-993.

This is the entirety of testimony and evidence provided by EDD at trial. EDD’s 

argument for the invalidity of claim 2 is based on EDD’s attorney argument that “The 

specification makes clear that the refractive index interface of the illumination coupler 

claimed in claim 1 is a ‘surface configured for total internal reflection of light incident 

thereon.’” Dkt. No. 457 at 3. According to EDD, since TIR is specified in claim 1 

through interpretation of the “refractive index interface,” the further limitation of TIR in 

claim 2 is redundant. 

SSC responds that the presumption under the doctrine of claim differentiation 

requires the Court to construe “refractive index interface” in a way that would not make 

claim 2 redundant, i.e., that it does not require TIR. Dkt. No. 460 at 2. 

The Court finds that EDD has failed to meet its burden to demonstrate that claim 2 

is an improper claim by clear and convincing evidence. Ultimately, this question is one of 

claim construction. EDD did not ask the Court to construe “refractive index interface,” nor 

did it move for summary judgment on this claim. Dr. Pollock’s conclusion that claim 2 is 

redundant because Dr. Pollock does not know “what it adds” is unpersuasive. Dr. Pollock 

did not testify to the argument that EDD’s counsel puts forward, that the “refractive index 

interface” in claim 1 would be interpreted as a person of ordinary skill in the art as

requiring TIR, and that a person ordinary skill in the art would find claim 2 redundant.

Additionally, Dr. Pollock provides no reasoning for his cursory conclusion, and he did not 

opine as to whether one of ordinary skill in the art would agree with his conclusion.

III. CONCLUSION

The Court finds that claim 2 of the ’554 patent is not invalid.

IT IS SO ORDERED.

Dated: April 8, 2016 _____________________________________

NATHANAEL M. COUSINS

United States Magistrate Judge

Case 3:13-cv-05038-NC Document 467 Filed 04/08/16 Page 3 of 3