In a previous post, I discussed the new LED patent dispute between Osram, Samsung and LG Electronics (LG).  There were a few significant developments last month.

First, the U.S. International Trade Commission (ITC) decided to investigate allegations raised in two Osram complaints that Samsung and LG are infringing a number of Osram patents by importing certain LEDs into the U.S.  See my prior post for a discussion of some of these patents.

Also, Samsung and LG each responded with suits of their own in both the ITC and Delaware federal court in which they accuse Osram of patent infringement. 

Samsung’s Delaware complaint (Samsung-Osram_Complaint) asserts eight patents, six relating to LED structure and two concerning methods of making LEDs. 

U.S. Patents Nos. 7,268,372 and 7,893,443 are entitled, respectively, ”Vertical GaN light emitting diode and method of manufacturing the same” and “Nitride based semiconductor light-emitting device” and are directed to gallium nitride LEDs having particular layered structures. 

U.S. Patent No. 7,282,741 (’741 Patent) is directed to a vertical type nitride LED wherein an n-side electrode comprises a bonding pad (261) formed adjacent to an edge of an upper surface of the n-type nitride semiconductor layer (21).  An extended electrode (262) is formed in a band from the bonding pad (261).

According to the ’741 Patent, the bonding pad prevents a wire from shielding light emitted from the active layer of the LED, and the extended electrode prevents concentration of current density, thereby ensuring effective distribution of the current density.

The other patents asserted by Samsung in the Delaware lawsuit are:

U.S. Patent No. 7,959,312, entitled “White light emitting device and white light source module using the same” and directed to white LEDs having a blue LED chip with red and green phosphors disposed around it that emit light having certain color coordinates;

U.S. Patent No. 7,964,881, entitled “Semiconductor light emitting device, method of manufacturing the same, and semiconductor light emitting package using the same” and directed to an LED having an electrode layer with an area exposed by a contact hole formed through a first conductivity type semiconductor layer;

U.S. Patent No. 7,771,081, entitled “LED package and backlight unit using the same” and directed to an LED package having a simplified lens shape with an increased beam angle; and

U.S. Patents Nos. 6,551,848 and 7,838,315, relating to methods of manufacturing LEDs and vertical LEDs, respectively.

Samsung’s Delaware complaint lists Osram’s TOPLED, Dragon Family, and OSLON lines of products.

In its Delaware suit (LG-Osram_Complaint), LG asserts eight patents against Osram.  Like the patents asserted by Osram against Samsung and LG, many of these LG patent relate to technology for converting blue LED light into white light.

Three related patents – U.S. Patents Nos. 6,841,802, 7,649,210 and 7,956,364 – entitled “Thin film light emitting diode,” are directed to an LED comprising an LED chip (30) emitting blue light, a thin film layer (86) over the LED chip, and a passivation layer (80) between the thin film layer and the LED chip.

The thin film layer (86) contains a fluorescent material such as phosphor or a compound containing tin and converts the blue light to white light.

The other LG patents include:

U.S. Patent No. 7,821,024, entitled “Semiconductor light emitting device having a roughness layer” and directed to an LED wherein one of the conductive semiconductor layers includes a “horn-shaped roughness” to change the incident angle of light emitted and enhance external quantum efficiency;

U.S. Patents Nos. 7,768,025 and 7,868,348, directed to LEDs having vertical topology and vertical structure, respectively, to improve luminous efficiency and reliability;

U.S. Patent No. 7,884,388, entitled “Light emitting diode having a first GaN layer and first semiconductor layer each having a predetermined thickness and fabrication method thereof”; and

U.S. Patent No. 7,928,465, entitled “Method of fabricating vertical structure LEDs” and directed to methods of making GaN LEDs on insulating substrates.

By my count, there are now at least 30 patents at issue in the several lawsuits filed by Osram, Samsung and LG.  And we’re still in the beginning stages of this growing LED patent war.

In a major new global LED patent war, Osram has sued Samsung and LG in several forums around the world, including the U.S. International Trade Commission, Delaware and California federal courts, Germany, and (against LG only) in Japan and China.

According to the California complaint against LG (Osram-LG-Complaint) Osram’s conversion technologies, which enable production of white LEDs using blue-emitting semiconductors, are the subject of the asserted patents, and a host of LG flat screen televisions contain infringing LEDs.

The patents-in-suit number up to a dozen and include at least three patent families. 

The first family of patents is entitled “Light-radiating semiconductor component with a luminescence conversion element” and relates to technologies for converting blue light to white light.  This family includes U.S. Patents Nos. 6,812,500, 7,078,732, 7,126,162, 7,151,283, 7,345,317 and 7,629,621 (Luminescence Patents).

The Luminescence Patents are directed to an LED component comprising a semiconductor body (1) fixed onto a first electrical terminal (2). 

The free surfaces of the semiconductor body (1) and parts of first and second electrical terminals (2, 3) are directly enclosed by a luminescence conversion encapsulation (5) made of an inorganic luminescent material. 

For white-light-emitting components, the Luminiscence Patents specify Y₃Al₅O₁₂:Ce³⁺ as the luminescent material.

In another embodiment, illustrated in Figure 2, the semiconductor body (1) and parts of the electrical terminals (2, 3) are enclosed by a transparent encapsulation (15) that does not effect any wavelength change.  A luminescence conversion layer (4) is applied to the transparent encapsulation (15).

In this case the luminescence conversion layer (4) is treated with a luminescent material (6).  A lens (29) reduces total reflection of the radiation within the luminescence conversion layer (4).

According to the Luminescence Patents, these structures provide homogeneous, polychromatic white light and simplify mass production by making the components more easily reproducible.

Another patent family includes U.S. Patents Nos. 6,459,130, 6,927,469 and 7,199,454, entitled “Optoelectronic semiconductor component” and U.S. Patent No. 6,975,011, entitled “Optoelectronic semiconductor component having multiple external connections.” (Optoelectronic Patents). 

These patents are directed to an LED component with a semiconductor chip (1) secured on a chip carrier part (2), a parallelepipedal encapsulation (3), a connection part (10), and external connections (11, 12).

A trough (4) is formed in the region of the chip carrier part (3), which holds the semconductor chip (1).  The inner surface (5) of the trough (4) has a truncated cone shape and forms a reflector for the radiation emitted by the semiconductor chip (1). 

According to the Optoelectronic Patents, this configuration provides increased radiant intensity.

A third family of patents is entitled “Optical semiconductor device with multiple quantum well structure” and includes U.S. Patents No. 6,849,881 and 7,106,090, directed to a superlattice LED structure formed of layers of nitride semconductor material.

Osram also has asserted U.S. Patent No. 7,271,425, entitled “Optoelectronic component,” and U.S. Patent No. 7,427,806, entitled “Semiconductor component emitting and/or receiving electromagnetic radiation, and housing base for such a component.”

Samsung is fighting back, though, with a patent infringement suit of its own against Osram in a district court in Seoul, Korea.

With the growth and promise of this sector, LED patent litigation has become white hot, and the lawsuits just keep coming (see posts here and here).  Osram’s California complaint sums it up well:

Business in this area is growing rapidly and has taken on major strategic importance.

CAO Group (CAO) is a Utah-based company that designs and sells a variety of dental, veterinary, forensic and lighting products including the Dynasty line of LED lamps.

CAO owns U.S. Patents Nos. 6,465,961 (’961 Patent), 6,634,770 (’770 Patent), and 6,746,885 (885 Patent), which relate to LED technology embodied by the Dynasty lamps.

Earlier this month CAO asserted the ’961, ’770 and ’885 Patents against a host of LED lamp makers.  The patent infringement complaint (CAO_Complaint), filed in federal court in Utah, names as defendants GE Lighting, Osram Sylvania, Lighting Science Group, Nexxus Lighting, Sharp Electronics, Toshiba, Feit Electric Company, and Lights of America.

The asserted patents are directed to an LED light source (100) with a heat sink (104) that has multiple panels (104b-i).  Each panel may host one or more LED chips (106), which can be arranged to transmit light in multiple directions.

The arrangement of panels (104b-i) can be varied to facilitate emission of light from the LED chips (106) based on the desired directions of light.

Figure 6 shows that the heat sink (403) may include a lining of thermal electric material (405) that lines an air chamber (406).

By applying a voltage to the thermal electric material (405), its temperature can be lowered and heat can be drawn from the heat sink material (403), which in turn draws heat away from the LED chips (402).

According to the asserted patents, this LED lamp structure efficiently dissipates the heat produced by the LEDs. 

CAO’s complaint is the latest in the very hot area of LED patent infringement litigation and the third such suit filed in the last month (see my post about the Cree and Takion suits here).

LED patent litigation remains hot, with two new lawsuits filed last month.  In the first, North Carolina LED maker Cree sued SemiLEDs Optoelectronics (SemiLEDs), alleging that SemiLEDs’ MvpLED product line infringes six patents.

The complaint (Cree-Semileds-Complaint), filed in U.S. District Court for the Middle District of North Carolina, asserts U.S. Patent Nos. 7,737,459 (’459 Patent), 7,211,833 (’833 Patent), 7,611,915 (’915 Patent), 6,657,236 (’236 Patent), 7,795,623 (’623 Patent), and 7,557,380 (’380 Patent).

The ’833 and ’915 Patents are part of a family that relates to gallium nitride LEDs having a silicon carbide (SiC) substrate in a “flip-chip” mounted configuration, i.e., the LED is mounted so the substrate side faces upwards away from the LED package, or submount. 

An LED (100) includes a substrate (20) and an epitaxial region (30) on the substrate.  There is a multilayer conductive stack (35) and an ohmic layer (32) on the epitaxial region (30) opposite the substrate (20). 

A reflector layer (34) is on the ohmic layer (32) opposite the epitaxial region, and a barrier layer (36) is opposite the reflector layer (34). 

According to the ’833 and ’915 Patents, this configuration has several advantages over existing SiC-based LEDs, including increased resistance to high temperatures, higher shear strength of bonds between the LED and the submount, and improved conductivity.

The ’236 Patent is directed to LEDs having light extraction structures, which boost efficiency by reflecting, refracting or scattering light so that more light escapes the LED. 

The ’380 and ’623 Patents relate to LEDs having a reduced conductivity region aligned with a non-transparent feature such as a wire bond pad, and the ’459 Patent is directed to an LED having particular output characteristics (radiant flux at 20 milliamps current of at least 29 milliwatts at its dominant wavelength).

In the second case, a Japanese company called Takion sued a host of LED manufacturers including GE, LEDtronics, Sharp, Philips, and Toshiba for infringement of U.S. Patent No. 6,577,072 (’072 Patent).

According to the complaint (Takion-GE_Complaint), filed in federal court in Seattle, various LED lamp devices produced by the defendants infringe the ’072 Patent, including GE’s LED7PAR20/NFL, LEDtronic’s ATS-200R-5 LED traffic light replacement lamp, and Philips’ 5E-26A60 product.

The ’072 Patent is directed to an LED lamp and power supply unit that can be directly connected to an AC power supply.  The power supply unit includes a wave rectifier and an electric power output.

The unit is configured so the output admits electric power only when the voltage of the rectified wave corresponding to each half period of the wave of the AC power supply voltage is equal to or heigher than a predetermined value.

According to the ’072 Patent, the invention allows direct connection of the LED lamp to an AC power supply without unduly comprising efficiency or losing too much power by heat dissipation.

These two complaints are the latest in a recent surge of LED patent litigation, including a suit between Philips and Seoul Semiconductor and enforcement by Nichia and Altair Engineering.

Dutch electronics giant Philips and its LED subsidiary Philips Lumileds Lighting Company (collectively “Philips”) have launched the opening shot in what could become a major green patent war.

In a complaint (Philips-Seoul-Complaint) filed last month in federal court in Santa Ana, California, Philips accused its Korean rival Seoul Semiconductor (Seoul) of infringing five patents relating to LED technology and asserted that one of Seoul’s “fundamental” semiconductor structure patents is invalid.

The Philips patents-in-suit are:

U.S. Patent No. 5,779,924, entitled “Ordered interface texturing for a light emitting device,” directed to an LED with a textured interface that improves light extraction;

U.S. Patent No. 6,274,924, entitled “Surface mountable LED package,” directed to an LED package with a heat sinking slug that is thermally isolated from the package’s metal leads;

U.S. Patent No. 6,547,249, entitled “Monolithic series/parallel LED arrays formed on highly resistive substrates,” directed to an array of LEDs wherein the p- and n- contacts are on the same side of the array and the individual LEDs are electrically isolated from each other by trenches or by ion implantation;

U.S. Patent No. 6,590,235, entitled “High stability optical encapsulation and packaging for light-emitting diodes in the green, blue, and near UV range,” directed to an LED component wherein the LED chip is encapsulatd by a rigid outer optically transmissive shell and an interior optically transmissive gel or resilient layer; and

U.S. Patent No. 6,717,353, entitled “Phosphor converted light emitting device,” directed to an LED device that includes a wavelength converting material Sr-SiON:Eu²⁺ which absorbs light emitted by the LED and emits light of a longer wavelength.

The accused products include Seoul’s Acriche, Top View, High Flux, Side View and Z-Power LEDs.

Philips is also seeking a declaratory judgment that its own products don’t infringe Seoul’s U.S. Patent No. 5,075,742 (’742 Patent) and that the ’742 Patent is invalid. 

The ’742 Patent is entitled “Semiconductor structure for optoelectronic components with inclusions” and is directed to a structure having plural layers in semiconductor material.  One of the layers includes stacked sub-layers, with each sub-layer having three dimensional “inclusions” – improved electron-hole areas – and a narrow band gap. 

According to the ’742 Patent, this structure overcomes certain problems in production of ”III-V” semiconductors (so named for the columns of the Periodic Table in which the semiconductor materials are classified).

According to the complaint, Philips has a reasonable apprehension of being sued for infringement of the ’742 Patent because of a press releases and public statements by Seoul calling the patent “fundamental to indium gallium nitride-based light emitting device technology,” and characterizing a recent court decision as holding that it would be “impossible for LEDs that use InGaN in their active layers” to avoid infringement of the ’742 Patent.

The complaint also alleges that Seoul has threatened the “entire LED community,” and in discussions with Philips, specifically mentioned a European patent that is related to the ’742 Patent.

These are major LED players with big litigation warchests so this could turn into a major green patent war.  This only a couple of years after Seoul wrapped up an epic LED patent battle with its Japanese competitor Nichia.

Japanese LED maker Nichia has initiated another patent infringement suit, this time against a Washington state hand tool company called Wilmar Corporation (Wilmar). 

The complaint (nichia-wilmar-complaint.pdf), filed in the Eastern District of Texas in Marshall, accuses Wilmar of infringing U.S. Patent Nos. 5,998,925 (’925 Patent), 7,531,960 (’960 Patent), 5,652,434 (’434 Patent) and 6,093,965 (’965 Patent).

The ’925 and ’960 Patents are members of the same patent family.  The two related patents describe a light emitting diode (100) that minimizes deterioration in emission light intensity by including a phosphor in the coating resin (101) that covers the light emitting component (102). 

According to the ’925 Patent, incorporating a phosphor in the LED reduces deterioration: 

the phosphor used in the light emitting device has excellent resistance against light so that the fluorescent properties thereof experience less change even when used over an extended period of time while being exposed to light of high intensity.  This makes it possible to reduce the degradation of characteristics during long period of use and reduce deterioration due to light of high intensity emitted by the light emitting component . . . to provide a light emitting device which experiences less color shift and less luminance decrease.

The ’434 and ’965 Patents, entitled “Gallium nitride-based III-V group compound semiconductor,” are related patents in a different family. 

The “III-V” in the title refers to those columns of the periodic table, and the full title means a nitride semiconductor of a Group III element containing gallium, such as GaN, GaAlN, InGaN or InAlGaN.

These patents are directed to an LED (10) having an electrically insulating substrate (11) and a layer (12) of an n-type gallium nitride-based III-V Group compound semiconductor on a surface (11a) of the substrate. 

A layer (13) of a p-type gallium nitride-based III-V Group compound semiconductor is formed on the surface of the n-type semiconductor layer (12) (the “p” means that extra positive charge is added to the semiconductor; the “n” means extra negative charge is added).

A p-type electrode (15) covers the surface of the p-type semiconducting layer (13), which is partially etched away to partially expose the surface of the n-type semiconductor layer (12).  An n-type electrode (14) is formed on the exposed surface portion of the n-type semiconductor layer (12).

The p-type electrode (15) is connected with a bonding wire (21) at a bonding pad (17) formed on a portion of the surface of the p-type electrode (15).

According to the ’434 and ’965 Patents, prior gallium nitride-based III-V semiconductors suffered from conductivity problems. 

They also required that light be observed on the side of the substrate, opposite the side of the semiconductor layers, which led to large chip sizes.  

According to the ’434 and ’965 patents, the patented structure is a major improvement for this type of LED and alleviates these problems.   

Nichia’s complaint doesn’t name any specific accused products, but Wilmar makes headlamps and flashlights that incorporate LED lighting.

Nichia has aggressively asserted its LED patents in recent years, including in a global patent war against Korean rival Seoul Semiconductor that the parties settled last year.