An LED light bulb, comprising: a lamp housing, a bulb base, connected with the lamp housing; a stem with a stand extending to the center of the lamp housing, disposed in the lamp housing; a single flexible LED filament, disposed in the lamp housing, the flexible LED filament comprising: a plurality of LED sections, each of the LED sections includes at least two LED chips that are electrically connected to each other by a wire; a plurality of conductive sections comprising a conductor, located between the adjacent two LED sections; a light coversion layer disposing on the LED chip and at least two sides of the conductive electrodes and exposing a portion of the conductive electrodes, the light coversion layer is composed of at least one top layer and at least one base layer, where the top layer only cover the LED chip and the conductor completely and exposes a portion of the wire.

A light emitting device includes a plurality of unit light emitting regions on a substrate. At least one of the unit light emitting regions includes at least one pair of first and second electrodes that are spaced apart, at least one first bar-type LED in a first layer on the substrate, and at least one second bar-type LED in a second layer on the substrate. At least one of the first bar-type LED or the second bar-type LED is electrically connected between the first electrode and the second electrode.

An LED light bulb, comprising: a lamp housing, a bulb base, connected with the lamp housing; a stem with a stand extending to the center of the lamp housing, disposed in the lamp housing; a single flexible LED filament, disposed in the lamp housing, and the flexible LED filament comprising: two LED sections, each of the LED sections comprising a least one LED chip; one conductive section comprising a conductor, located between the adjacent two LED sections; two conductive electrodes, disposed corresponding to the two LED sections and electrically connected to the two LED sections, wherein points of the flexible LED filament in an xyz coordinates are defined as X, Y, and Z, an x-y plane of the xyz coordinates is perpendicular to the height direction of the light bulb, a z-axis of xyz coordinates is parallel with the stem, and the main bending points of the LED sections and the conductive electrodes are substantially on the circumference centered on the conductive section in the XY plane.

In one embodiment, an LED lamp has a generally bulb shape. The LEDs are low power types and are encapsulated in thin, narrow, flexible strips. The LEDs are connected in series in the strips to drop a desired voltage. The strips are affixed to the outer surface of a bulb form to provide structure to the lamp. The strips are connected in parallel to a power supply, which may be housed in the lamp. Since many low power LEDs are used and are spread out over a large surface area, there is no need for a large metal heat sink. Further, the light emission is similar to that of an incandescent bulb. In other embodiment, there is no bulb form and the strips are bendable to have a variety of shapes. In another embodiment, a light sheet is bent to provide 360 of light emission. Many other embodiments are described.

An LED-filament comprising: a partially light-transmissive substrate; a plurality of blue LED chips mounted on a front face of the substrate; first broad-band green to red photoluminescence materials and a first narrow-band manganese-activated fluoride red photoluminescence material covering the plurality of blue LED chips and the front face of the substrate; and second broad-band green to red photoluminescence materials covering the back face of the substrate. The LED-filament can further comprise a second narrow-band manganese-activated fluoride red photoluminescence material on the back face of the substrate in an amount that is less than 5 wt % of a total red photoluminescence material content on the back face of the substrate.

An LED-filament includes a partially light-transmissive substrate; blue LED chips mounted on a front face of the substrate; first broad-band green to red photoluminescence materials and a first narrow-band manganese-activated fluoride red photoluminescence material covering the blue LED chips and the front face of the substrate; and second broad-band green to red photoluminescence materials covering the back face of the substrate. The LED-filament can further include a second narrow-band manganese-activated fluoride red photoluminescence material on the back face of the substrate in an amount that is less than 5 wt % of a total red photoluminescence material content on the back face of the substrate.

An LED light bulb includes a bulb shell, a bulb base, a stem, conductive supports, an LED filament, and a supporting arm. The bulb base is connected to the bulb shell. The stem is connected to the bulb base. The conductive supports are connected to the stem. The LED filament includes a filament body and two conductive electrodes. The conductive electrodes are at two ends of the filament body and connected to the conductive supports. The filament body is around the stem. The supporting arm is connected to the stem and the filament body. In a height direction of the LED light bulb, H is a distance from a bottom to a top of the bulb shell. A first height difference is defined between the two conductive electrodes and is from 0 to 1/10H. The filament body is curved to form a highest point and a lowest point. A second height difference is defined between the highest point and the lowest point. The first height difference is less than the second height difference.

A light-emitting device including a substrate with a top surface and a bottom surface opposite to the top surface and a plurality of LED chips disposed on the top surface and configured to generate a top light visible above the top surface and a bottom light visible beneath the bottom surface, each LED chip comprising a plurality of light-emitting surfaces. The substrate has a thickness greater than 200 m and comprises aluminum oxide, sapphire, glass, plastic, or rubber. The plurality of LED chips has an incident light with a wavelength of 420-470 nm. The top light and the bottom light have a color temperature difference of not greater than 1500K.

An illumination device includes a supporting base, and a light-emitting element inserted in the supporting base. The light-emitting element includes a substrate having a supporting surface and a side surface, a light-emitting chip disposed on the supporting surface, and a first wavelength conversion layer covering the light-emitting chip and only a portion of the supporting surface without covering the side surface.

An LED light bulb, comprising: a bulb shell with a lower part and an upper part opposite to the lower part; a bulb base connected with the bulb shell; a heat dissipating element connected with the lower part of the bulb shell and the bulb base, wherein the height of the heat dissipating element is L1 and the maximum height from the heat dissipating element to the upper part of the bulb shell is L2, and the ratio of L1 to L2 is from 1/30 to 1/3; and an LED filament with a plurality of LED chips electrically connected to each other disposed in the bulb shell, two conductive supports, disposed in the bulb shell, a driving circuit, electrically connected with the two conductive supports and the bulb base, a stem disposed in the bulb shell, the LED filament is connected with the stem through the conductive supports.