Quantum dot light source device, backlight module, and liquid crystal display device

What is this patent about?

’710 is related to the field of display technologies, specifically focusing on backlight units that utilize quantum dot materials to enhance color gamut. In typical liquid crystal displays, blue LEDs are used to excite quantum dots to produce red and green light, which then mix to form white light. However, because LED emission follows a Lambertian distribution, the light intensity is significantly higher at the center than at the edges, often leading to non-uniform color profiles such as a bluish tint at the center and a yellowish tint at the periphery.

The underlying idea behind ’710 is to achieve spatial color uniformity by selectively recycling light at the center of the light source where the blue light intensity is highest. By introducing a gradient of reflectivity across the exit substrate, the invention forces a higher percentage of photons at the center to bounce back into the quantum dot layer for a secondary conversion cycle. This process specifically reduces the excess blue component and increases the red and green components at the center, effectively balancing the color spectrum across the entire emission surface.

The claims of ’710 focus on a quantum dot light source device featuring a package bracket that forms a closed cavity containing an LED chip and a multi-layered quantum dot component. The core requirement of the independent claims is the presence of reflection points arranged on the upper substrate of the package. These points are configured such that the reflectivity is higher at the center of the substrate than at its peripheral edges, ensuring that the light-recycling effect is concentrated where the exciting light is most intense.

In practice, this variable reflectivity is achieved by manipulating the physical characteristics of the reflection points, such as increasing their size or density toward the center of the substrate. The device may also incorporate a dichroic light-transmitting layer on the lower substrate, which is engineered to allow blue exciting light to pass through while reflecting red and green excited light back toward the exit face. This dual-layer approach maximizes light extraction efficiency while maintaining strict control over the final color balance of the planar light source.

This approach differs from prior solutions that relied on uniform quantum dot distributions, which inherently struggled with the non-uniform output of the underlying LED. By using a spatially modulated reflection pattern, the invention compensates for the natural physics of LED emission without requiring complex, non-uniform deposition of the quantum dot material itself. The result is a more robust backlight module that provides a consistent, wide-gamut white light across the entire display area, eliminating common defects like center-to-edge color shifting.