See-Through Display Backlight Zoning for Higher Image Contrast
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Solution Overview
Problem
Existing display devices struggle to achieve high contrast between image and see-through portions, as light from sidelight devices propagates to both areas, reducing the visibility of images.
Innovation Solution
A display device with a light source control circuit that selectively activates or deactivates light emitters in specific areas to enhance contrast by controlling light emission patterns, using a field-sequential system to improve visibility and reduce light absorption losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light from a sidelight device propagates to both image and see-through portions, then the display device can maintain transparency in see-through portions, but the contrast of the image portion deteriorates
Solution Approach 1:
The light source is divided into multiple light emitters arranged in a specific pattern, with some emitters positioned to illuminate the see-through portion and others to illuminate the image portion. This segmentation allows independent control of lighting in different regions, enabling the see-through portion to remain transparent while the image portion maintains high contrast.
Solution Approach 2:
Different regions of the display device are provided with different lighting characteristics. The see-through portion receives light from specific emitters to maintain transparency, while the image portion receives light from other emitters to ensure high contrast. This local differentiation of lighting quality resolves the contradiction between transparency and contrast.
2Illumination intensity
If all light emitters are activated, then the overall brightness of the display device is improved, but the contrast between image and see-through portions deteriorates
Solution Approach 1:
The light source control circuit dynamically controls the activation state of different light emitters based on the display content and viewing conditions. By selectively activating or deactivating specific emitters, the system maintains overall brightness while preserving the contrast between image and see-through portions, resolving the contradiction between global brightness and local contrast.
Solution Approach 2:
The light emitters are controlled to operate in periodic or sequential patterns, with different emitters being activated at different times or in different cycles. This periodic control allows the system to maintain average brightness levels while ensuring that at any given moment, the contrast between image and see-through portions is preserved through selective illumination.
3Illumination intensity
If light emitters are arranged along the side surface, then the light distribution is improved, but light absorption losses increase
Solution Approach 1:
Instead of arranging light emitters in a traditional planar configuration, the invention positions light emitters along the side surface of the display device, utilizing the lateral dimension for light injection. This dimensional change enables more uniform light distribution across the display area while reducing the path length through which light must travel, thereby minimizing absorption losses.
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 solution enhances image contrast by selectively illuminating areas, reducing discomfort from background visibility and improving overall display quality.
Implementation Method 1
a light source disposed so as to emit light into a side surface of the first light-transmitting substrate, a side surface of the second light-transmitting substrate, or a side surface of the glass base member
Implementation Method 2
a liquid crystal layer including polymer-dispersed liquid crystals enclosed between the first and the second light-transmitting substrates
Data Source
AI summary
According to an aspect, a display device includes: a display panel including a first light-transmitting substrate, a second light-transmitting substrate, and a liquid crystal layer and having an active area and a peripheral area; a light-transmitting glass base member bonded to the display panel; a light source; and a light source control circuit. The light source includes light emitters arranged in a first direction. The light source control circuit is configured to bring at least one of the light emitters in a first area into a light-emitting state and bring at least one of the light emitters in a second area other than the first area into a non-light-emitting state, and the first area is an area that overlaps an area obtained by extending an image area including an image in the active area in a second direction orthogonal to the first direction.