Curved Light Guide with Constant-Angle Diffractive Elements
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Solution Overview
Problem
Existing display devices with flat light guide members suffer from outside light reflection entering the user's eyes, causing discomfort and require complex curved holographic diffractive optical elements, making them difficult to manufacture.
Innovation Solution
A display device with a curved light guide body and optical elements where the angle of the optical elements relative to the light propagation direction remains constant, allowing for easier manufacturing and effective redirection of outside light away from the user's eyes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a flat light guide member is used, then the device structure is simple, but outside light reflection enters the user's eyes causing discomfort
Solution Approach 1:
The patent applies curvature to the light guide member by providing a curved reflective surface instead of a flat one. This curved surface redirects outside light away from the user's eyes, eliminating the harmful reflection effect while maintaining structural simplicity. The curvature transforms the geometric configuration to achieve the desired light redirection function.
2Object-affected harmful factors
If a curved holographic diffractive optical element is used to redirect outside light, then outside light reflection is inhibited, but the element becomes difficult to manufacture
Solution Approach 1:
The patent segments the optical system into separate functional components: a curved reflective surface for light redirection and a diffractive optical element for image generation. By separating the curvature function from the holographic function, the diffractive optical element can be manufactured as a flat, simpler component while the curved surface handles the light redirection, thus reducing manufacturing complexity.
Solution Approach 2:
The patent introduces a curved reflective surface as an intermediary component between the outside light source and the diffractive optical element. This intermediary redirects the outside light before it reaches the optical element, allowing the element itself to remain flat and easier to manufacture while still achieving the goal of inhibiting harmful light reflection.
3Reliability
If the optical element angle varies across the element, then light redirection is optimized, but the manufacturing precision requirements increase
Solution Approach 1:
The patent divides the light redirection function from the optical element by introducing a separate curved reflective surface. This allows the optical element to maintain a constant angle throughout, simplifying manufacturing and alignment, while the curved surface handles the variable angle light redirection needed for optimal performance.
Solution Approach 2:
Instead of varying the optical element angle to achieve light redirection, the patent inverts the approach by keeping the optical element at a constant angle and using a curved reflective surface to perform the redirection. This inversion simplifies the optical element's manufacturing requirements while maintaining effective light control.
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 effectively inhibits outside light from entering the user's eyes while simplifying the production of optical elements by maintaining a consistent angle, enhancing user comfort and manufacturing ease.
Implementation Method 1
an optical element that diffracts and emits light propagating inside the light guide plate
Data Source
AI summary
A display device includes a light guide body and displays an image of light emitted from the light guide body. The light guide body is of a curved shape, and includes a light guide plate and an optical element that diffracts and emits light propagating inside the light guide plate. The optical element is provided in the light guide body so that the angle of the optical element relative to a propagation direction in which the light propagates inside the light guide plate is constant irrespective of where in the optical element.