Integrated Backlighting Using Diffractive Out-Coupling
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Solution Overview
Problem
Current liquid crystal display (LCD) structures waste light due to the absorption of unwanted light and are unnecessarily thick due to the stacking of films, with the backlight structure being separate from the display panel substrate.
Innovation Solution
An integrated display device structure with a first substrate for launching and diffractively coupling multiple colors of light to pre-selected pixels or subpixels, using optical layers with diffraction gratings and a modulation layer between substrates to modulate light based on image data, allowing for efficient light out-coupling and polarization modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If white light is uniformly spread on the pixel array and filtered through color filters, then the display can show colors, but a lot of light is wasted in the absorption of unwanted light
Solution Approach 1:
The patent segments the white light into different color wavelengths (red, green, blue) using diffraction gratings before they reach the pixel array. This segmentation allows each color to be directed to specific pixels without requiring absorption-based color filters, thereby reducing light loss while maintaining color display capability.
Solution Approach 2:
The patent extracts the color separation function from the pixel level (where it causes light loss through absorption) and moves it to the backlight level using diffraction gratings. This extraction eliminates the need for color filters at each pixel, reducing light absorption waste while preserving the color filtering function.
2Length of stationary object
If the backlight structure is implemented as a separate panel from the display panel substrate, then the manufacturing is simplified, but the resulting structure is unnecessarily thick due to stacking of films
Solution Approach 1:
The patent merges the backlight structure with the display panel substrate by integrating diffraction gratings and optical layers directly into the display panel layers. This combining eliminates the need for a separate backlight panel, reducing overall thickness while managing the complexity through systematic integration of optical functions into existing layers.
Solution Approach 2:
The patent makes the display panel substrate serve multiple functions: it acts as both the display structure and the integrated backlight carrier. The substrate now supports both pixel formation and optical light guidance functions, reducing the need for separate structures and thereby reducing overall thickness.
3Illumination intensity
If multiple optical layers are stacked to provide diffractive out-coupling for different colors, then the color gamut is improved, but the structure becomes thicker
Solution Approach 1:
The patent transitions from stacking optical layers in the vertical dimension to arranging diffraction gratings in the horizontal plane on the same substrate. This dimensional change allows multiple color-specific optical elements to coexist without increasing thickness, as they are positioned side-by-side rather than stacked vertically.
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 solution results in improved light throughput efficiency, leading to brighter displays, reduced power consumption, a better color gamut, and a thinner component, while integrating the backlight component within the display device.
Implementation Method 1
one or more optical layers configured to provide diffractive out-coupling of portions of each of the plurality of lights of different colors to pre-selected pixels or subpixels of the pixels separately from other colors of the different colors
Implementation Method 2
the modulation layer may be a liquid crystal and the light modulation may be provided for varying a state of optical polarization of the portions of each of the plurality of lights of different colors
Implementation Method 3
the at least one optical layer may be configured to provide the launching the plurality of lights using at least one of prism coupling, edge coupling, grating coupling and butt coupling
Data Source
AI summary
The specification and drawings present a new apparatus and method for designing and using display devices with integrated backlight layer structure utilizing separate color diffractive out-coupling (e.g., diffraction out-coupling). A lower substrate of the display can be used to integrate the backlight component (or the backlight layer structure), thus enabling a thin module with the integrated backlighting.