Direct type backlight module
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Solution Overview
Problem
Traditional direct-type LED backlight modules fail to meet the high light uniformity requirements of automotive displays, achieving only 75% uniformity in the 25-point light uniformity test, whereas automotive displays need at least 85% uniformity.
Innovation Solution
A direct type backlight module design featuring a light guide component with varying thicknesses and optical microstructures on its light incident surface to adjust light intensity distribution, eliminating intensity differences and enhancing uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional direct-type LED backlight modules are used, then the device structure is simple and manufacturing is easy, but the light uniformity is insufficient (only 75% in 25-point test)
Solution Approach 1:
The light guide component employs varying thickness design where different regions have different thicknesses to compensate for non-uniform light distribution. Thicker regions are positioned where light intensity is higher, and thinner regions where light intensity is lower, achieving uniform light output across the display surface.
Solution Approach 2:
The patent changes the physical parameter of the light guide component by varying its thickness across different regions. This parameter modification allows the light guide to differentially transmit light from the LED array, converting the non-uniform light distribution into a uniform output pattern.
2Length of moving object
If the optical cavity height is reduced to achieve thinness, then the backlight module becomes thinner, but the light uniformity and brightness distribution become difficult to control
Solution Approach 1:
The light guide component is designed with spatially varying thickness to compensate for the limited optical cavity height. This local quality variation enables effective light uniformity control within a compact thickness of 2.5 cm, as different thickness regions provide differential light transmission paths.
Solution Approach 2:
Instead of controlling light uniformity only through the vertical dimension (optical cavity height), the patent introduces thickness variation in the horizontal plane of the light guide component. This dimensional transition allows uniformity control without increasing overall module thickness.
3Illumination intensity
If high brightness and high color saturation are achieved, then the display quality improves, but the light uniformity across the display surface deteriorates
Solution Approach 1:
The varying thickness design of the light guide component creates local differences in light transmission. Regions with higher incident light intensity from bright LEDs use thicker light guide material to reduce transmission, while regions with lower intensity use thinner material to increase transmission, achieving uniformity while preserving overall brightness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves light uniformity exceeding 85% in the 25-point test, reducing the optical cavity height to 2.5 cm while maintaining thinness, suitable for automotive displays.
Implementation Method 1
The light guide component has a light incident surface with optical microstructures... the light guide component is disposed between the at least one optical film and the light-emitting elements
Data Source
AI summary
A backlight module includes a circuit board, light-emitting elements and a light guide component. The light emitting elements are disposed on the circuit board. The light emitting elements include a first light emitting element and a second light emitting element. The light emitting elements are disposed between the light-guiding element and the circuit board. There are no other optical elements between the light-guiding element and the light emitting elements. The light-guiding element has a light guiding portion, and the light guiding portion is composed of a light-transmitting material. The light guiding portion includes at least two first light guiding portions and a second light guiding portion. The first light guiding portions are respectively disposed above the first light emitting element and the second light emitting element. The second light guiding portion is disposed between the first light guiding portions.