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.