Backlight Device with Directional Light Sources for Parallax Display
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Solution Overview
Problem
Existing display technologies face issues with displaying clear images to users sitting directly in front of the panel, as they often result in mixed images, poor usability due to oblique display angles, and reduced brightness due to partial light shielding by parallax barriers.
Innovation Solution
A backlight device configuration featuring a first prism sheet with a triangular prism row and two light sources, one emitting light directly and the other with controlled directivity, allows for light irradiation in the front, left, and right directions by utilizing the first prism sheet's slanted surfaces for reflection and refraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a parallax barrier is used to display different images to left and right viewers, then parallactic images can be displayed, but the transmission light is partially shielded causing the display to become dark
Solution Approach 1:
The light guide plate is divided into multiple light emission regions (first, second, third light emission regions) that emit light in different directions. This segmentation allows different parts of the display to serve different viewing purposes: front viewing and oblique viewing, without requiring a parallax barrier that would block light.
Solution Approach 2:
Instead of using a parallax barrier that blocks light in the vertical dimension, the invention uses directional light emission from the backlight in the horizontal dimension. The light guide plate emits light at different angles from different regions, creating parallax effects without obstructing the light path.
2Adaptability or versatility
If the image forming layer is divided into two for left and right viewers, then different images can be displayed, but the number of pixels of the displayed image becomes half
Solution Approach 1:
Different regions of the light guide plate have different light emission characteristics. The first light emission region emits light primarily in the front direction, the second region emits in oblique directions, and the third region provides additional directional control. This local differentiation allows the full pixel array to serve multiple viewing angles simultaneously.
Solution Approach 2:
The single image forming layer serves multiple functions by receiving directional light from different regions of the backlight. The same pixel array can display images visible from the front, from oblique angles, or both simultaneously, eliminating the need to divide the pixel layer.
3Adaptability or versatility
If light sources are disposed at different two light-incident end surfaces of a light guide plate, then light rays can be irradiated at angles corresponding to parallax, but two images are displayed in a mixed manner in the front direction when a main user sits just in front of the display panel
Solution Approach 1:
Different regions of the light guide plate are designed with specific light emission characteristics. The first light emission region emits light primarily in the front direction with controlled angles, while the second region emits in oblique directions. This spatial differentiation ensures that front viewers receive clear, non-mixed images while oblique viewers receive parallactic images.
Solution Approach 2:
The system dynamically controls which light emission regions are active based on the desired viewing mode. By selectively activating different light emission regions, the system can optimize for either front viewing clarity or oblique viewing parallax, or a combination of both, without fixed image mixing problems.
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 configuration enables uniform light distribution and bright image display in all directions, improving usability and reducing light leakage, thus providing clear images to users regardless of their position.
Implementation Method 1
a first prism sheet which has a triangular prism row on a major surface thereof; a first light source which emits light having directivity in a slanted direction with respect to a normal line direction of a light outgoing surface of the first prism sheet so as to enter into the triangular prism row of the first prism sheet
Implementation Method 2
a first light source which emits light having directivity in a slanted direction with respect to a normal line direction of a light outgoing surface of the first prism sheet so as to enter into the triangular prism row of the first prism sheet
Data Source
AI summary
A backlight device includes: a first prism sheet which has a triangular prism row on a major surface thereof; a first light source which emits light having directivity in a slanted direction with respect to a normal line direction of a light outgoing surface of the first prism sheet in opposite side to the triangular prism row side so as to enter into the triangular prism row of the first prism sheet; and a second light source which emits light having directivity in the normal line direction of the light outgoing surface of the first prism sheet so as to enter into the triangular prism row of the first prism sheet.