Display Apparatus Asymmetric Modulating Surface for Circular Light Spot
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Solution Overview
Problem
In projection systems, the use of total internal reflection prisms leads to a change in light intensity distribution, resulting in reduced optical utilization and image quality due to elliptical light beam divergence, which is not efficiently managed by existing technologies.
Innovation Solution
A display apparatus utilizing a narrowband light source with an elliptical light distribution and a reflection device with a modulating surface at a preset angle to the optical axis, ensuring a circular light spot formation, thereby enhancing optical utilization and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a total internal reflection prism is used to modulate light in a projection system, then the light can be separated into modulated and image components, but the light intensity distribution changes from circular to elliptical, reducing optical utilization
Solution Approach 1:
The patent applies asymmetry by tilting the modulating surface at a preset angle (e.g., 45 degrees) relative to the optical axis. This asymmetric orientation transforms the elliptical light distribution into a circular distribution on the modulating surface, enabling the light spot to be efficiently collected by the projection lens diaphragm and improving optical utilization while maintaining the light modulation function
Solution Approach 2:
The patent changes the geometric parameter of the light path by introducing a preset angle between the optical axis and the modulating surface. This parameter change (angle adjustment) transforms the light intensity distribution from elliptical to circular, allowing the light spot to match the lens diaphragm aperture and reduce light loss
2Reliability
If the rotation angle of micro-mirrors in the DMD is increased to improve contrast, then the contrast ratio improves, but the beam divergence angle increases, causing the light spot to exceed the lens diaphragm and reducing optical efficiency
Solution Approach 1:
The patent uses asymmetric tilting of the modulating surface to compensate for the increased beam divergence angle. By setting the modulating surface at a preset angle, the elliptical light distribution with larger divergence is transformed into a circular distribution that fits within the lens diaphragm, allowing higher micro-mirror rotation angles to be used for improved contrast without light loss
Solution Approach 2:
The patent introduces a new dimensional parameter (the tilt angle of the modulating surface) to control the light distribution geometry. This additional degree of freedom allows independent optimization of both the micro-mirror rotation angle (for contrast) and the light spot shape (for optical efficiency), decoupling the two previously coupled parameters
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 increases optical utilization and improves image display quality by matching the light distribution with the lens diaphragm, reducing light loss and enhancing luminous efficiency.
Implementation Method 1
a reflection device including a reflection surface, where the reflection surface is configured to reflect the narrowband light to obtain a light to be modulated
Implementation Method 2
a light modulation device configured to modulate the light to be modulated, to obtain an image light of an image to be displayed
Data Source
AI summary
A display apparatus and a display system are provided. The display apparatus includes: a narrow-spectrum light source configured to emit narrow-spectrum light in elliptical distribution; a reflection device including a reflection surface for reflecting the narrow-spectrum light to obtain to-be-modulated light; and a light modulation device configured to modulate the to-be-modulated light to obtain image light of an to-be-modulated image. The light modulation device includes a modulation surface configured to receive the to-be-modulated light, the modulating surface is at a preset angle to an optical axis of the to-be-modulated light such that the to-be-modulated light forms a circle light spot on the modulating surface. The narrow-spectrum light complying with the elliptical distribution is incident onto the light modulation device to form a circle light spot, thereby helping the light modulation device to emit image light in circular angular distribution, improving light effect and achieving better image display quality.