Color Filterless Display Microprism Viewing Angle Correction
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Solution Overview
Problem
Conventional color filterless liquid crystal display devices face challenges in achieving wide color reproductivity and viewing angle due to limitations in viewing angle correction, leading to insufficient luminance and color balance, especially when using transmission diffraction grating films, which struggle to control diffraction efficiencies and maintain peak luminance.
Innovation Solution
The implementation of a color display device with a spectral structure that separates light into wavelength regions using a diffraction grating, followed by condensing and angle correction using a high refractive index layer and a low refractive index layer, forming a microprism or Fresnel-type microprism structure with tailored tilt angles for each sub-pixel to align emission angles symmetrically with the frontal direction, enhancing viewing angle correction and color reproductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a transmission diffraction grating film is used for viewing angle correction, then the viewing angle is improved, but the peak luminance is significantly lowered to 30-40%
Solution Approach 1:
The patent divides the viewing angle correction function into multiple segments: the diffraction grating handles wavelength separation, while the microprism structure handles angle correction. This segmentation allows each component to optimize its function without compromising the other, maintaining high luminance while achieving wide viewing angle.
Solution Approach 2:
The patent uses a composite optical system combining diffraction grating and microprism structures. The diffraction grating separates light by wavelength, and the microprism structure corrects emission angles, creating a composite solution that achieves both wide viewing angle and high peak luminance simultaneously.
2Manufacturing precision
If a diffraction grating is used to separate light into wavelength regions, then color reproductivity is improved, but the emission angles of different wavelengths become asymmetric, worsening viewing angle uniformity
Solution Approach 1:
The patent intentionally introduces asymmetry in the microprism structure to compensate for the asymmetry caused by diffraction. By designing prisms with specific asymmetric angles, the system corrects the wavelength-dependent emission angle deviations, restoring symmetry and achieving uniform viewing angle across all colors.
Solution Approach 2:
The patent applies different prism angles to different wavelength regions (R, G, B sub-pixels). Each sub-pixel receives a customized prism configuration that specifically corrects its wavelength's emission angle, achieving local optimization that results in global symmetry and uniform viewing angle.
3Duration of action of stationary object
If conventional diffusion films are used for viewing angle correction, then the emission angles are maintained, but color reproductivity and color balance cannot be equalized, worsening color uniformity
Solution Approach 1:
The patent replaces the conventional diffusion film mechanism with a refraction-based microprism structure. Instead of scattering light through diffusion, the microprisms precisely control light direction through refraction, enabling both wide viewing angle and accurate color uniformity that diffusion films cannot achieve.
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
This approach results in a display with wide color reproductivity, improved viewing angle, and reduced blur, achieving higher frontal luminance and color balance, with the microprism structure effectively correcting emission angles and enhancing color reproductivity beyond conventional methods.
Implementation Method 1
The white light incident from the wedge-shaped light guide plate 404 is separated by an optical element (spectral element) such as the diffraction grating 405
Implementation Method 2
a high refractive index layer is formed on a side onto which the light is made incident from the condensing element, a low refractive index layer is formed on an emitting side from which the light is emitted, and a predetermined interface is formed by these layers
Data Source
AI summary
A color filterless display device performing color display for expressing one pixel by three RGB sub-pixels includes: a light source; a diffraction grating for separating a light irradiated from this light source into lights of a plurality of wavelength regions; a cylindrical lens array for receiving the separated light and condensing the light while corresponding to each of the sub-pixels; and a liquid crystal cell including a structure portion for correcting an angle of the condensed light for all sub-pixels, wherein, in the structure portion of this liquid crystal cell, a side onto which a light from the cylindrical lens array is made incident is made of a high refractive index layer, an emitting side from which the light is emitted is made of a low refractive index layer, and a Fresnel-type microprism structure is formed by the high refractive index layer and the low refractive index layer.