Optical System Shielding Part for Stray Light Reduction
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Solution Overview
Problem
Existing image projection systems suffer from reduced light utilization efficiency due to unnecessary light, which affects image quality and performance.
Innovation Solution
An optical system with a lens array and a shielding part is used to redirect incident light, where the optical axis is misaligned from the center of the lens's effective diameter to minimize stray light and enhance light utilization efficiency, incorporating a digital micromirror device for directional light modulation and a shielding part to block unnecessary light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a wavelength-selective filter is used to reflect unnecessary light, then stray light is reduced, but light utilization efficiency deteriorates
Solution Approach 1:
The patent extracts and removes unnecessary light from the optical path using a shielding part positioned upstream from the lens, rather than using a wavelength-selective filter that would reflect and waste light. This extraction approach eliminates stray light while preserving useful light transmission.
Solution Approach 2:
The patent introduces a shielding part as an intermediary element that selectively blocks unnecessary light before it reaches the lens, acting as a mediator between the light source and the optical modulation element to prevent stray light without interfering with the main optical path.
2Object-affected harmful factors
If an aperture is used to cut out stray light, then interference region is removed, but light loss increases
Solution Approach 1:
Instead of using an aperture to cut out interference light, the patent extracts unnecessary light upstream from the lens using a shielding part, removing the harmful light before it can enter the optical system and cause interference, thereby avoiding light loss in the main path.
Solution Approach 2:
The shielding part performs preliminary action by blocking unnecessary light upstream from the lens before it can reach the optical modulation element or cause interference, preventing the problem rather than correcting it downstream.
3Ease of operation
If the optical axis is centered on the lens, then alignment is simplified, but unnecessary light enters the lens
Solution Approach 1:
The patent introduces asymmetry by deliberately offsetting the optical axis from the center of the lens's effective diameter. This asymmetric positioning, combined with the shielding part, allows the system to block unnecessary light while maintaining proper alignment of useful light, resolving the contradiction between simplified alignment and stray light reduction.
Solution Approach 2:
The shielding part creates local quality by selectively blocking light in specific regions upstream from the lens, allowing different parts of the optical path to have different light transmission characteristics - blocking unnecessary light while transmitting useful light.
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 optical system effectively reduces unnecessary light and improves light utilization efficiency, leading to enhanced image projection performance and quality.
Implementation Method 1
an optical modulation element configured to reflect and emit an incident light in a different direction
Implementation Method 2
an illumination optical system includes a lens array and a lens disposed in an order listed from an upstream side of an optical path
Data Source
AI summary
An optical system (300) includes an optical modulation element (103) to reflect an incident light (250) in a different direction, and an illumination optical system (301) through which light emitted from a light source (101) is emitted toward the optical modulation element (103). The illumination optical system (301) includes a lens array (14A, 14B), a lens (15) disposed in an order listed from an upstream side of an optical path, and a shielding part (50) disposed upstream from the lens (15) on the optical path. The shielding part (50) shields light incident on an effective diameter of the lens (15). In a direction perpendicular to an optical axis of the light emitted from the light source (101), the optical axis (101A) is shifted from a center position (15M) of the effective diameter of the lens (15) in an opposite direction with reference to the shielding part (50).