Optical Scanning Apparatus With Inclined Waveplate End Plane
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Solution Overview
Problem
Optical scanning apparatuses face challenges with large size due to diagonal positioning of components, distortion in projection planes requiring costly corrections, and significant stray light issues due to anti-reflection film inefficiencies.
Innovation Solution
Integration of a prism and waveplate with an inclined end plane to redirect stray light away from the projection plane, combined with a compact prism design to minimize space usage and prevent distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the laser source and collimator lens are positioned diagonally before the mirror, then the optical scanning apparatus can function properly, but the apparatus occupies a large amount of space
Solution Approach 1:
The patent repositions the laser source and collimator lens from a diagonal arrangement to a side arrangement relative to the mirror. This spatial reconfiguration changes the dimensional layout of optical components, allowing the beam to enter the mirror perpendicularly while reducing the overall footprint of the apparatus.
Solution Approach 2:
The patent introduces asymmetric positioning of optical components by placing the laser source and collimator lens at the side of the mirror rather than diagonally. This asymmetric arrangement optimizes space utilization while maintaining proper optical function.
2Ease of operation
If the laser beam is reflected by a standard prism, then the optical path is redirected, but stray light is generated at the center of the projection plane
Solution Approach 1:
The patent converts the potentially harmful stray light reflection into a beneficial outcome by positioning the waveplate's end plane at a specific angle. The stray light that would normally hit the projection plane is redirected to a different location, effectively eliminating the harmful effect while maintaining the optical path control function.
Solution Approach 2:
The waveplate serves as an intermediary element between the prism and the mirror. Its inclined end plane acts as a mediator that redirects stray light, preventing it from reaching the projection plane while allowing the main optical path to function correctly.
3Reliability
If a waveplate with a perpendicular end plane is used, then the laser beam is polarized, but stray light reflects onto the projection plane
Solution Approach 1:
The patent changes the angular parameter of the waveplate's end plane from perpendicular (0 degrees) to inclined (non-zero degrees). This parameter modification allows the waveplate to maintain its polarization function while simultaneously redirecting stray light away from the projection plane.
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 reduces the size of the optical scanning apparatus, eliminates distortion in projection planes, and significantly minimizes stray light, enhancing image projection quality without increasing manufacturing costs.
Implementation Method 1
a prism (30) and a waveplate (40) positioned before (in front of) the mirror (150)... the laser beam L11 irradiated from the laser source (110) becomes a parallel beam by passing through the collimator lens (120) and is perpendicularly incident to an end face of the prism (130) located toward the laser source (110). Then, the laser beam L11 changes direction by being reflected at the inside of the prism (130)
Implementation Method 2
The waveplate (140) polarizes the laser beam L11 and the reflection light L12, so that the reflection light L12 reflected from the mirror (150) is transmitted through the prism (130) without being reflected by the prism (130)
Implementation Method 3
Although the waveplate (140) includes an end plane (140E) having an anti-reflection film (not illustrated), approximately 0.5% of the laser beam L11 is reflected at the end plane (140E)
Data Source
AI summary
An optical scanning apparatus includes a laser source configured to irradiate a laser beam, a prism configured to reflect the laser beam irradiated from the laser source, a mirror configured to move the laser beam reflected from the prism by oscillating with respect to a predetermined axis and reflecting the laser beam reflected from the prism, the laser beam reflected from the prism being substantially perpendicular to a plane of the mirror in a case where the mirror is in a non-oscillating state, a waveplate positioned between the prism and the mirror and configured to polarize the laser beam reflected from the prism and the laser beam reflected from the mirror. The waveplate includes an end plane inclined with respect to the laser beam reflected from the prism to the mirror.