Backlight Optical Member Positioning for LCD Uniformity
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Solution Overview
Problem
The positioning accuracy of optical members with curved end surfaces in liquid crystal display devices is compromised due to the difficulty in using curved surfaces as references, leading to reduced accuracy and uneven brightness in the emitted light.
Innovation Solution
A lighting device configuration that includes a positioning portion with a positioning hole and a positioning protrusion, and a rotation restricting portion with an optical member recess and contact portion, which together ensure accurate positioning and prevent rotation of the optical member, even when it has a curved end surface, thereby maintaining high light use efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the optical member has a curved end surface, then the aesthetic appearance and light distribution are improved, but the positioning accuracy is reduced due to difficulty in using curved surfaces as references
Solution Approach 1:
The patent divides the positioning function into two separate components: a positioning portion (with positioning holes) that establishes the location, and a rotation restricting portion (with contact portions) that prevents rotation. This segmentation allows the curved end surface to maintain its aesthetic and optical properties while the separate positioning structures ensure accurate positioning.
Solution Approach 2:
The patent introduces positioning protrusions as intermediary elements that fit into positioning holes to establish precise positioning, and contact portions that act as mediators to restrict rotation. These intermediary structures enable accurate positioning without requiring the curved end surface to serve as a positioning reference.
2Ease of manufacture
If the positioning hole is made round or clearance is created, then the assembly ease is improved, but the rotation of the optical member occurs causing displacement
Solution Approach 1:
The patent separates the positioning function (round positioning holes for easy assembly) from the rotation restriction function (flat contact portions to prevent rotation). This allows the positioning holes to be round for ease of assembly while the contact portions ensure rotation is prevented.
Solution Approach 2:
The patent combines two functions into a single positioning structure: the positioning portion with round holes that facilitate assembly, and the rotation restricting portion with contact portions that prevent rotation. This merging allows both ease of assembly and rotation prevention to coexist in one integrated structure.
Data Source
AI summary
A backlight unite 12 includes LEDs 17, an optical member 16, a positioning portion 23, and a rotation restricting portion 24. The optical member 16 includes at least a curved end surface 16C having a curved shape in a plan view included in a periphery of the optical member 16. The positioning portion 26 includes a positioning hole 25 that opens through a thickness direction of the optical member 16 and a positioning protrusion 26 that is inserted in the positioning hole 25 and is in contact with an inner wall of the positioning hole 25. The rotation restricting portion 24 includes an optical member recess 27 that is a portion of the periphery of the optical member 16 recessed along a circumferential direction and a contact portion 28 that is in contact with the optical member recess 27.