Large angle illuminated LED filament light bulb
摘要
說明書
The factors affecting the light transmittance of the organosilicon-modified polyimide resin composition at least include the type of the main material, the type of the modifier (thermal curing agent), the type and content of the heat dispersing particles, and the siloxane content. Light transmittance refers to the transmittance of the light near the main light-emitting wavelength range of the LED chip. For example, blue LED chip has a main light-emitting wavelength of around 450 nm, then the composition or the polyimide should have low enough or even no absorption to the light having a wavelength around 450 nm, so as to ensure that most or even all the light can pass through the composition or the polyimide. In addition, when the light emitted by the LED chip passes through the interface of two materials, the closer the refractive indexes of the two materials, the higher the light output efficiency. In order to be close to the refractive index of the material (such as die bonding glue) contacting with the filament substrate (or base layer), the organosilicon-modified polyimide composition has a refractive index of 1.4?1.7, preferably 1.4?1.55. In order to use the organosilicon-modified polyimide resin composition as substrate in the filament, the organosilicon-modified polyimide resin composition is required to have good light transmittance at the peak wavelength of InGaN of the blue-excited white LED. In order to obtain a good transmittance, the raw materials for synthesizing the organosilicon-modified polyimide, the thermal curing agent and the heat dispersing particles can be adjusted. Because the phosphor in the organosilicon-modified polyimide resin composition may have certain effect on the transmittance test, the organosilicon-modified polyimide resin composition used for the transmittance test does not comprise phosphor. Such an organosilicon-modified polyimide resin composition has a transmittance of 86?93%, preferably 88?91%, or preferably 89?92%, or preferably 90?93%.
