Image Display Device Brightness Correction Stability
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Solution Overview
Problem
Existing image display devices face instability in brightness correction when the brightness of an input video signal changes continuously, particularly in varying ambient environments, as it is challenging to distinguish between changes caused by external illumination and the video signal itself.
Innovation Solution
An image display method and device that modulate incident light using a spatial optical modulating element, employing difference values and brightness correction characteristic data to accurately correct the brightness component of the input video signal based on ambient illuminance measurements, ensuring stable image projection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If brightness correction is performed based on reflected light measurement from screen, then color reproduction is improved, but stability of correction deteriorates when input video signal brightness changes continuously
Solution Approach 1:
The patent segments the brightness correction process into multiple independent components: separate correction for ambient light changes and separate correction for video signal brightness changes. By dividing the correction into distinct segments based on different light sources, the system can accurately distinguish between reflected light from ambient illumination and reflected light from the projected image, thereby maintaining correction stability during continuous brightness changes of the input video signal.
Solution Approach 2:
The patent introduces an intermediary measurement approach by measuring reflected light at multiple locations (including positions away from the screen) and using these intermediary measurements to calculate the ambient light component. This intermediary measurement process allows the system to separate the ambient light contribution from the video signal contribution, enabling stable brightness correction even when the input video brightness changes continuously.
2Adaptability or versatility
If reflected light from screen is used for brightness correction, then adaptation to ambient illumination is improved, but difficulty in distinguishing between ambient light changes and video signal changes increases
Solution Approach 1:
The patent segments the light measurement process by taking measurements at multiple spatial locations - both at the screen position and at positions away from the screen. By segmenting the measurement locations, the system can distinguish between light reflected from the screen (video signal related) and ambient light reflected from the environment, thereby reducing the difficulty of detecting and measuring the separate contributions of each light source.
Solution Approach 2:
The patent uses measurements taken at positions away from the screen as intermediary data to infer the ambient light component. These intermediary measurements serve as a proxy for ambient illumination without being contaminated by the projected image, making it easier to detect and measure the ambient light contribution separately from the video signal.
3Manufacturing precision
If continuous brightness adjustment is made for moving image video signals, then image quality is improved, but stability of brightness correction deteriorates due to overlapping light influences
Solution Approach 1:
The patent segments the brightness correction into independent correction terms: one for ambient light adaptation and another for video signal brightness adjustment. By segmenting the correction process this way, the system can apply continuous brightness adjustment for moving images without compromising correction stability, as each correction component operates independently based on its specific light source.
Solution Approach 2:
The patent uses intermediary measurements from multiple locations to calculate the ambient light component, which then serves as a stable reference for brightness correction. This intermediary approach allows continuous adjustment of the video signal brightness while maintaining correction stability, as the ambient light component derived from intermediary measurements remains consistent and separable from the video signal changes.
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 method and device achieve stable brightness correction by accurately accounting for the influence of the input video signal on ambient illuminance, effectively addressing the instability in brightness correction across changing environments.
Implementation Method 1
configured to modulate incident light with a spatial optical modulating element according to an input video signal so as to project an image onto a screen via a projection lens
Implementation Method 2
measuring the illuminance of the ambient environment repeatedly at regular time intervals by using an illuminance sensor
Implementation Method 3
project an image onto a screen via a projection lens
Data Source
AI summary
Difference values that are defined as values representing a magnitude of an influence exerted upon an illuminance of an ambient environment according to a brightness component of an input video signal and are set so as to correspond to the brightness component based on a result of measuring the magnitude of the influence previously, a plurality of illuminance ranges set by dividing an extent of the illuminance of the ambient environment, and brightness correction characteristic data for correcting the brightness component according to each of the illuminance ranges are stored. The brightness component is detected, so that the difference values are selected based on the detected value (S101), an illuminance sensor measures the illuminance of the ambient environment repeatedly (S102), one of the illuminance ranges is selected based on illuminance detection values obtained by previous and current measurements and the selected difference values (S103), and the brightness correction characteristic data according to the selected illuminance range is selected, so that the brightness component of the input video signal is corrected (S104). By reflecting the influence of reflected light from a screen due to image projection based on the input video signal, the brightness can be corrected stably according to a change in the brightness of the use environment.