A negative-type photosensitive resin composition that has a satisfactory imidization rate and can yield a resin layer with high chemical resistance, even under low-temperature curing conditions of 200° C. or below, the negative-type photosensitive resin composition containing a photopolymerization initiator (B) in a proportion of 0.1 part by mass to 20 parts by mass with respect to 100 parts by mass of a polyimide precursor (A), the polyimide precursor (A) being a polyamic acid ester or polyamic acid salt with a specific structure, and the weight-average molecular weight (Mw) of the polyimide precursor (A) being 3,000 or greater and less than 16,000, in terms of polystyrene, according to gel permeation chromatography (GPC).

The present disclosure relates to a polyimide precursor and flexible polyimide obtained by imidization of the polyimide precursor and having high transparency, high glass transition temperature and low coefficient of thermal expansion.

Boron nitride nanotube (BNNT)-polymide (PI) and poly-xylene (PX) nano-composites, in the form of thin films, powder, and mats may be useful as layers in electronic circuits, windows, membranes, and coatings. The processes described chemical vapor deposition (CVD) processes for coating the BNNTs with polymeric material, specifically PI and PX. The processes rely on surface adsorption of polymeric material onto BNNTs as to modify their surface properties or create a uniform dispersion of polymer around nanotubes. The resulting functionalized BNNTs have numerous valuable applications.

A polyimide film contains fluorinated substituents and cardo structures. The polyimide film exhibits excellent heat-resistance, transparency and mechanical properties. The polyimide film has a glass-transition temperature (Tg) of at least 360° C., a coefficient of thermal expansion (CTE) of 50 ppm/° C. or lower, a modulus of at least 4.0 Gpa, a b* value of 5 or lower and yellowness index of 8 or less. The polyimide film can be used as a display substrate or an optical film in a liquid crystal display (LCD), an organic light-emitting diode (OLED) and in other fields where the characteristic features are required.

A resin composition includes a prepolymer and an additive, wherein: the prepolymer is prepared from a mixture subjected to a prepolymerization reaction, and the mixture includes 100 parts by weight of a maleimide resin, 15 to 30 parts by weight of a siloxane compound and 4 to 16 parts by weight of a diamine compound; the maleimide resin includes bisphenol A diphenyl ether bismaleimide, 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethane bismaleimide or a combination thereof; the siloxane compound includes a compound of Formula (I), wherein n is an integer of 5 to 40; and the diamine compound includes a compound of Formula (II) or Formula (III). The resin composition is made by using a preparation method. The resin composition may be used to make various articles, such as a prepreg, a resin film, a laminate or a printed circuit board. ##STR00001##

A display panel includes the following elements: a substrate including a first base layer, wherein the first base layer includes a transparent polyimide resin; a first pixel circuit and a second pixel circuit over the substrate, spaced from each other with the transmission area between the first pixel circuit and the second pixel circuit, and each including transistors and a storage capacitor; a first display element electrically connected to the first pixel circuit; and a second display element electrically connected to the second pixel circuit.

Provided is a layered product that uses a high temperature-resistant transparent film having sufficient heat resistance, and that is capable of being mechanically released from an inorganic substrate after various processes are performed on the inorganic substrate since the adhesive strength between the high temperature-resistant transparent film and the inorganic substrate is appropriately weak, and that is less warped along with the inorganic substrate. In this layered product, no adhesive is used between the high temperature-resistant transparent film and the inorganic substrate, the release strength between the high temperature-resistant transparent film and the inorganic substrate is at most 0.3 N/cm, and the warpage amount of the layered product when heated at 300° C. is at most 400 .Math.m.

A polyimide copolymer according to the present invention has a particular structure in which siloxane structures are distributed in a nanosize in a polymer and thus enables excellent transparency, heat resistance, mechanical strength and flexibility and effective reduction of residual stress, and thus can be used in various fields such as a substrate for a device, a cover substrate for a display, an optical film, an integrated circuit (IC) package, an adhesive film, a multi-layer flexible printed circuit (FPC), tape, a touch panel and a protective film for an optical disk.

A solar cell including a semiconductor substrate having a first conductivity type an emitter region, having a second conductivity type opposite to the first conductivity type, on a first main surface of the semiconductor substrate an emitter electrode which is in contact with the emitter region a base region having the first conductivity type a base electrode which is in contact with the base region and an insulator film for preventing an electrical short-circuit between the emitter region and the base region, wherein the insulator film is made of a polyimide, and the insulator film has a C.sub.6H.sub.11O.sub.2 detection count number of 100 or less when the insulator film is irradiated with Bi.sub.5.sup.++ ions with an acceleration voltage of 30 kV and an ion current of 0.2 pA by a TOF-SIMS method. The solar cell can have excellent weather resistance and high photoelectric conversion characteristics.

A solar cell including a semiconductor substrate having a first conductivity type an emitter region, having a second conductivity type opposite to the first conductivity type, on a first main surface of the semiconductor substrate an emitter electrode which is in contact with the emitter region a base region having the first conductivity type a base electrode which is in contact with the base region and an insulator film for preventing an electrical short-circuit between the emitter region and the base region, wherein the insulator film is made of a polyimide, and the insulator film has a C.sub.6H.sub.11O.sub.2 detection count number of 100 or less when the insulator film is irradiated with Bi.sub.5.sup.++ ions with an acceleration voltage of 30 kV and an ion current of 0.2 pA by a TOF-SIMS method. The solar cell can have excellent weather resistance and high photoelectric conversion characteristics.