Backlight kit

A backlight kit, comprising:

• a base member comprising a concave structure;
• a light diffusion covering member combined with the base member, wherein the base member is covered by the light diffusion covering member;
• a light guide module disposed within the concave structure of the base member, wherein the light guide module has a light diffusion structure region facing the light diffusion covering member, and the light diffusion structure region has light diffusion microstructures that are distributed from sparse to dense;
• an illumination module located beside a side of the light guide module away from the light diffusion structure region, wherein the illumination module emits a light beam to the light guide module, the illumination module comprises a circuit board, a light-shielding plate and at least one light-emitting unit, wherein the at least one light-emitting unit is disposed on a first surface of the circuit board and emits the light beam to the light guide module, and the light-shielding plate is disposed on a second surface of the circuit board, wherein the first surface and the second surface of the circuit board are opposed to each other;
• and
• a translucent black gradient light-transmissible element located over illumination module and arranged between the light guide module and the light diffusion covering member,
• wherein the translucent black gradient light-transmissible element comprises a first opaque black ink layer, a sharp gradient light-transmissible black ink layer and a smooth gradient light-transmissible black ink layer, wherein the sharp gradient light-transmissible black ink layer is arranged between the first opaque black ink layer and the smooth gradient light-transmissible black ink layer, a width of the sharp gradient light-transmissible black ink layer is smaller than a width of the smooth gradient light-transmissible black ink layer, the first opaque black ink layer is aligned with the illumination module, and the sharp gradient light-transmissible black ink layer and the smooth gradient light-transmissible black ink layer are aligned with the light diffusion structure region,
• wherein a transmittance of the sharp gradient light-transmissible black ink layer is gradually changed from 0% to 50% in a direction from the first opaque black ink layer to the smooth gradient light-transmissible black ink layer,
• wherein a transmittance of the smooth gradient light-transmissible black ink layer is gradually changed from 50% to 100% in a direction from a side near the sharp gradient light-transmissible black ink layer to a side away from the sharp gradient light-transmissible black ink layer
• wherein after the light beam is exited from the light diffusion structure region, the light beam is transmitted through the sharp gradient light-transmissible black ink layer and the smooth gradient light-transmissible black ink layer, so that a smooth and luminance-gradient visual effect is produced on the light diffusion covering member.