Backlight Unit Aspheric Lens Segmentation for Light Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid crystal display devices face inefficiencies in power consumption and uneven plane emission due to mismatched aspect ratios between the light guide plate's incident and emission surfaces, leading to light loss and reduced polarization when using a cylindrical Fresnel lens to collimate light.
Innovation Solution
A backlight unit comprising a light source, a first lens, and a second lens that diffuses light into parallel light by controlling beam widths in different directions, ensuring the light guide unit's incident surface matches the light's aspect ratio, minimizing light loss and maintaining polarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cylindrical Fresnel lens is added to converge parallel light greater than the incident surface in vertical width, then the aspect ratio of light is adjusted to match the incident surface, but light loss occurs inside the lens
Solution Approach 1:
The patent divides the single cylindrical Fresnel lens into two separate aspheric lenses. The first aspheric lens collimates light in the vertical direction, and the second aspheric lens collimates light in the horizontal direction. This segmentation eliminates the need for a third lens to adjust aspect ratio, thereby preventing additional light loss while achieving proper aspect ratio matching.
Solution Approach 2:
The patent changes the optical parameters by using aspheric surfaces instead of cylindrical Fresnel surfaces. The aspheric lenses have specific curvature radii and thicknesses that are optimized to collimate light in both directions simultaneously, achieving aspect ratio matching without the light loss associated with additional lens elements.
2Ease of operation
If light is reflected multiple times within the light guide plate to guide light, then light is directed to the emission surface, but the degree of polarization is reduced
Solution Approach 1:
The patent replaces the mechanical reflection system (multiple reflections within the light guide plate) with an optical system using aspheric lenses. The lenses collimate light before it enters the light guide plate, allowing light to travel in a more direct path with fewer reflections, thereby preserving the degree of polarization while still achieving effective light guiding.
3Area of stationary object
When light is irradiated onto the incident surface such that horizontal beam width matches horizontal width of incident surface, then light coverage is maximized, but vertical width of optical path exceeds vertical width of incident surface causing light loss
Solution Approach 1:
The patent segments the collimation function into two separate aspheric lenses that independently control horizontal and vertical beam widths. This allows precise matching of both horizontal and vertical dimensions to the incident surface area, preventing light loss from excessive optical path width while maximizing light coverage.
Solution Approach 2:
The patent uses aspheric lens parameters (curvature radii, thicknesses, positions) to precisely control the beam width in both horizontal and vertical directions. This enables simultaneous optimization of light coverage and aspect ratio matching, eliminating the trade-off between coverage and light loss.
4Loss of energy
When light is irradiated onto the incident surface such that vertical beam width matches vertical width of incident surface, then light loss is minimized, but horizontal width of optical path becomes less than horizontal width of incident surface causing uneven plane emission
Solution Approach 1:
The patent segments the collimation control into two independent aspheric lenses, one for vertical direction and one for horizontal direction. This allows the vertical beam width to be optimized for minimizing light loss while the horizontal beam width is independently optimized for achieving uniform plane emission across the entire incident surface.
Solution Approach 2:
The patent adjusts the parameters of the two aspheric lenses independently to achieve different beam width optimizations. The first lens parameters are optimized for vertical beam width matching, and the second lens parameters are optimized for horizontal beam width expansion, thereby achieving both light loss minimization and uniform plane emission.
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 solution reduces power consumption and achieves even plane emission by efficiently guiding light with minimal loss and preserving polarization, improving display quality and efficiency.
Implementation Method 1
first and second aspheric lenses which collimate light from the light-emitting apparatus as parallel light
Implementation Method 2
cylindrical Fresnel lens which converges the parallel light transmitted through the first and second aspheric lenses to a light guide plate
Implementation Method 3
light guide plate which emits planar light
Data Source
AI summary
According to one embodiment, a backlight unit includes a light source, a first lens, a second lens, and a light guide unit. The light source emits light which is diffused as the light travels in a first-A direction, the light being diffused in a second direction intersecting the first-A direction, and a third direction intersecting the first-A direction and the second direction. The first lens and the second lens are arranged in an optical path of the light. The first and second lenses control the light such that the first lens controls a beam width of the light in the second direction, and the second lens controls a beam width of the light in the third direction, thereby converting the light into parallel light.