An LED filament and an LED light bulb applying the same are provided. The LED filament includes a at least one LED section, wherein the at least one LED section comprises at least two LED chips electrically connected to each other through a first wire, and at least two conductive electrodes, wherein each of the at least two conductive electrodes is electrically connected to corresponding one of the at least one LED section; and a light conversion layer, covering the at least one LED section and a portion of each of the at least two conductive electrodes, a portion of the first wire is exposed outside the light conversion layer.

The present disclosure relates to a method for manufacturing a polyimide film and a polyimide film manufactured thereby. In one embodiment, the method for preparing a polyimide film includes: preparing a polyamic acid by polymerizing a mixture containing an aromatic diamine and an aromatic acid dianhydride; preparing a first composition containing the polyamic acid, an amine-based catalyst, an acid anhydride-based dehydrating agent, and a solvent; and forming a polyimide film at 150° C. or less using the first composition, wherein the first composition contains the amine-based catalyst and the acid anhydride-based dehydrating agent in a molar ratio of 1:2 to 1:5.

The present invention relates to a transparent polyimide film containing a polyimide and a phosphate ester. The content of the phosphate ester based on 100 parts by mass of the polyimide is 3 parts by mass or more, preferably 5 to 100 parts by mass. It is preferable to use a phosphate ester that has a high birefringence reduction effect and with which a decrease in the tensile modulus of the film is small. In production of the polyimide film, it is preferable to employ a method in which: a solvent-soluble polyimide resin and a phosphate ester are dissolved in an organic solvent exhibiting solubility with respect to the polyimide resin to prepare a polyimide solution; the polyimide solution is applied onto a substrate; and the organic solvent is removed.

The present invention relates to a transparent polyimide film containing a polyimide and a phosphate ester. The content of the phosphate ester based on 100 parts by mass of the polyimide is 3 parts by mass or more, preferably 5 to 100 parts by mass. It is preferable to use a phosphate ester that has a high birefringence reduction effect and with which a decrease in the tensile modulus of the film is small. In production of the polyimide film, it is preferable to employ a method in which: a solvent-soluble polyimide resin and a phosphate ester are dissolved in an organic solvent exhibiting solubility with respect to the polyimide resin to prepare a polyimide solution; the polyimide solution is applied onto a substrate; and the organic solvent is removed.

Provided are a composition for forming a polyimide film, a method for preparing the same, and a use thereof. According to an implementation, a polyimide film which has excellent heat resistance, is flexible, and has excellent bending properties, without deteriorating colorless and transparent optical properties may be provided. In addition, the polyimide film according to an implementation may be useful for various flexible display devices.

A method for manufacturing a polyimide composite film for a flexible metal-clad substrate includes the following steps, providing a polyamide acid solution; providing fluorine polymer particles and mixing the fluorine polymer particles with a dispersant and an organic solution to prepare a fluorine polymer particle dispersion; forming a colloidal polyimide film from the polyamide acid solution; and coating the colloidal polyimide film with the fluorine polymer particle dispersion and then performing baking to form a polyimide composite film.

The present invention provides an electrochromic polyamic acid material, a preparation method thereof and a display device, wherein the molecular structure of the electrochromic polyamic acid material includes oligoaniline and carbazolyl triphenylamine. The oligoaniline serves as an electrochemically sensitive group, and the carbazolyl triphenylamine serves as a fluorescence emitting group. The electrochromic polyamic acid material is an electrically controlled fluorescent polymer. Fluorescence intensity of the electrochromic polyamic acid material undergoes reversible fluorescence conversion with a change of an applied voltage, due to a redox reaction of the oligoaniline at different voltages, resulting in an interchange between a benzene ring and an anthracene ring in a molecular structure, and an electron/energy transfer path with the fluorescence emitting group are generated or eliminated, thereby realizing the electrically controlled fluorescent properties of the electrochromic polyamic acid material.

Embodiments in accordance with the present invention encompass polyamic acid or polyimide polymers containing a reactive maleimide end group as well as photosensitive compositions made therefrom which are useful for forming films that can be patterned to create structures for microelectronic devices, microelectronic packaging, microelectromechanical systems, optoelectronic devices and displays. In some embodiments the compositions of this invention are shown to feature excellent hitherto unachievable mechanical properties. The negative images formed therefrom exhibit improved thermo-mechanical properties, among other property enhancements.

In a first aspect, a single layer polymer film includes 60 to 99 wt % of a crosslinked polyimide, having a gel fraction in the range of from 20 to 100% and a refractive index of 1.74 or less, and 1 to 40 wt % of a colorant. A surface of the single layer polymer film has been textured and has a maximum roughness (S.sub.pv) of 6 μm or more, an L* color of 30 or less and a 60° gloss of 15 or less. In a second aspect, a coverlay for a printed circuit board includes the single layer polymer film of the first aspect. In third and fourth aspects, processes are disclosed for forming a single layer polymer film including a crosslinked polyimide film including a dianhydride and a diamine.

Disclosed herein are a highly thick polyimide film that contains a reduced number of bubbles therein and exhibits high elasticity and high heat resistance, and a manufacturing method therefor. The polyimide film is obtained by imidizing a poly(amic acid) solution containing an acid dianhydride component including 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA), and pyromellitic dianhydride (PMDA), and a diamine component including 4,4′-oxydianiline (ODA), para-phenylenediamine (p-phenylenediamine, PPD), and 3,5-diaminobenzoic acid (DABA), and contains a phosphorus (P)-based compound.