PTAB

IPR2015-00487

LG Display Co Ltd v. Innovative Display Technologies LLC

Key Events

Petition

Title: Light Emitting Panel Assemblies
Brief Description: The ’660 patent discloses light emitting panel assemblies, typically used for backlighting Liquid Crystal Displays (LCDs). The technology involves a transparent panel member (an optical conductor) that efficiently conducts light from a side-mounted source and emits it from an output area using a pattern of surface "deformities."

Prior Art Relied Upon: Tai (Patent 5,359,691) and Funamoto (Patent 5,619,351).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Tai disclosed all elements of independent claim 1, upon which challenged claim 28 depends. Tai teaches a backlighting assembly with a planar optical conductor (light pipe 14), a plurality of light sources, a transition region (collimating assemblies 28), and a pattern of deformities (pyramid microprisms 36). Funamoto, a patent for a surface-type illumination device, was argued to supply the limitations of claims 25 and 28: a tray or housing for the assembly and a reflecting sheet associated with the bottom surface of the optical conductor.
- Motivation to Combine: Petitioner contended that both Tai and Funamoto address the common goal of creating efficient backlighting for LCDs and disclose similar mechanical configurations. A person of ordinary skill in the art (POSITA) would combine the efficient optical assembly of Tai with the well-known tray and reflector structure of Funamoto to create a complete, robust, and manufacturable product.
- Expectation of Success: A POSITA would have a reasonable expectation of success because combining an optical assembly with a standard housing and reflector was a conventional and predictable design choice in the field of LCD backlights.

Prior Art Relied Upon: Tsuchiyama (Patent 5,548,271) and Tsunoda (Japanese Patent Application Publication JP H5-210014).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner asserted that Tsuchiyama, which discloses a backlight for a radio pager, teaches a light emitting assembly comprising a planar optical conductor (light conducting plate 38), a plurality of LEDs (12a, 12b), and an integrated tray (rectangular saucer-like reflection frame 36). However, Tsuchiyama does not explicitly disclose a pattern of light-extracting deformities. This limitation was argued to be taught by Tsunoda, which discloses an LCD backlight guiding plate with a plurality of protrusions (deformities) that are varied to achieve uniform brightness.
- Motivation to Combine: A POSITA would be motivated to combine the teachings because both references are directed toward creating LCD devices with uniform brightness. To improve the uniformity of Tsuchiyama's backlight, a known problem in the art, a POSITA would have looked to solutions like Tsunoda and incorporated its teachings on using surface deformities to control light output.
- Expectation of Success: The use of surface deformities to control light extraction from a light guide was a known and predictable technique, ensuring a high expectation of success in achieving more uniform illumination.

Prior Art Relied Upon: Oe (Patent 5,711,589) and Etsuo (Japanese Patent Application Publication JP 07-064078).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Oe discloses a plane light source unit with most elements of claim 1, including a planar light guide with at least one input edge, a transition region ("zone 0"), and an output region with deformities (roughened surfaces or lens units) to control light emission. Etsuo was argued to supply the remaining elements, including the use of LEDs as the light source and a reflector (reflector 60) that also functions as a tray to contain the optical conductor and lamp units.
- Motivation to Combine: Petitioner asserted that a POSITA would combine these references as they are in the same field of backlighting for LCDs. A POSITA would be motivated to replace the fluorescent lamp in Oe with the more stable and efficient LEDs taught by Etsuo. Furthermore, combining Oe’s optical design with Etsuo’s integrated reflector-tray structure would result in a more compact and mechanically stable assembly, a known design goal.
- Expectation of Success: Substituting a known light source like a fluorescent lamp with another known light source like an LED, and placing an optical assembly into a known tray structure, were both predictable design modifications with a high likelihood of success.

"deformities" (Claims 1 and 33): Petitioner argued that, based on the patent's explicit definition, this term should be construed to mean "any change in the shape or geometry of a surface and/or coating or surface treatment that causes a portion of the light to be emitted." This construction is central to mapping various prior art features, such as microprisms, protrusions, and roughened surfaces, to the claim limitation.

Petitioner requests institution of an inter partes review and cancellation of claims 1, 3, 5, 10, 13, 16, 17, 25-29, and 33-35 of the ’660 patent as unpatentable under 35 U.S.C. §103.