Image Display Apparatus Brightness Control via Total Pixel Analysis
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Solution Overview
Problem
Conventional image display apparatus using computer-generated holograms (CGH) methods face challenges in maintaining desired brightness due to variations in the number of high-brightness pixels in the input image, leading to inconsistent brightness and color deviations, especially during moving image displays and text character presentations.
Innovation Solution
An image display apparatus that includes a light source emitting coherent light, a spatial modulation element to diffract light based on an input image, and a control unit calculating the total brightness of all pixels, which adjusts the light source or spatial modulation element to ensure the virtual image is displayed at a desired brightness, independent of pixel variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a plurality of diffraction grating patterns are superimposed to display images with many high-brightness pixels, then the input image can be displayed, but the diffraction grating patterns become unclear and diffracted light is reduced causing lower brightness
Solution Approach 1:
The patent applies preliminary action by calculating the total brightness of the input image before generating the diffraction grating pattern. Based on this pre-calculated total brightness, the system determines the optimal diffraction grating pattern parameters in advance, ensuring that the pattern remains clear and effective regardless of the number of high-brightness pixels in the input image.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the diffraction grating pattern parameters based on the total brightness of the input image. When the total brightness changes, the system modifies the diffraction grating pattern accordingly to maintain optimal diffraction efficiency and image brightness, resolving the contradiction between displaying many pixels and maintaining brightness.
2Illumination intensity
If laser light is concentrated on a small number of high-brightness pixels, then the diffraction grating patterns are clear, but the virtual image pixels are displayed at higher brightness than required
Solution Approach 1:
The patent applies feedback by using the calculated total brightness of the input image as a control parameter to adjust the diffraction grating pattern generation. This feedback mechanism ensures that the output virtual image brightness is proportional to the input image total brightness, preventing over-brightness when few pixels are displayed and under-brightness when many pixels are displayed.
3Device complexity
If the diffraction efficiency is kept uniform, then the display process is simple, but the brightness and color of the virtual image change with variations in the number of high-brightness pixels
Solution Approach 1:
The patent employs parameter changes by making the diffraction grating pattern parameters dependent on the total brightness parameter of the input image. This single parameter change approach maintains relative simplicity while achieving stable brightness and color output, as the system only needs to calculate and adjust based on the total brightness value rather than complex per-pixel adjustments.
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 apparatus effectively maintains consistent brightness and color across varying input images by dynamically controlling light output or spatial modulation patterns, thereby stabilizing the display quality regardless of pixel density changes.
Implementation Method 1
a spatial modulation element which diffracts coherent light from the light source and displays a virtual image by the diffracted light
Data Source
AI summary
An image display apparatus, including: a light source which emits coherent light; a spatial modulation element which diffracts the coherent light by displaying a diffraction grating pattern corresponding to an input image and which displays a virtual image by the diffracted light; and a control unit which calculates a total brightness representing a sum total of brightnesses of all pixels of the input image, and controls at least one of the light source and the spatial modulation element in such a manner that, if the total brightness has decreased, the virtual image is displayed at a lower brightness than a reference virtual image displayed when the input image is used directly.