Wide-color-gamut optical diaphragm, preparation method thereof and LED (Light Emitting Diode) backlight module

The invention provides a wide-color-gamut optical diaphragm, a preparation method thereof and an LED (Light Emitting Diode) backlight module with the diaphragm. The wide-color-gamut optical diaphragm comprises a first fluorescence conversion layer and a second fluorescence conversion layer which are arranged in a laminated manner, wherein the first fluorescence conversion layer is formed through mixing a first fluorescence conversion material and thermosetting colloid, the second fluorescence conversion layer is formed through mixing a second fluorescence conversion material and thermosetting colloid, the first fluorescence conversion material is a fluorescence conversion material with peak absorption in the wave band range of 460-510nm, and the second fluorescence conversion material is a fluorescence conversion material with peak absorption in the wave band range of 550-620nm. By adopting the optical diaphragm provided by the invention, a wider color gamut can be realized on the basis of not changing the LED color purity of the backlight module and the filtering performance of a CF (Color filter).