Optical Scanning Device Asymmetric Mirror Segmentation
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Solution Overview
Problem
Existing optical scanning devices face challenges in achieving high accuracy position detection with low driving power due to limited light receiving area and interference from direct light deflection between emission and reception regions.
Innovation Solution
The optical scanning device employs a swingable coupling portion and frame supporting a first reflecting portion as a light receiving mirror and a second reflecting portion as a light emitting mirror, positioned outside the ring-shaped frame, eliminating non-contributory regions and reducing air resistance, allowing for greater deflection angles with lower driving power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single mirror is used for both laser light emission and reflected light reception, then the device complexity is reduced, but the light receiving area is limited due to the need to secure a laser light emitting region on the mirror
Solution Approach 1:
The single mirror is divided into two separate mirrors: a light receiving mirror and a light emitting mirror. This segmentation allows each mirror to be optimized for its specific function, with the light receiving mirror having a large light receiving area and the light emitting mirror having a dedicated emitting region, thereby resolving the contradiction between device simplicity and light receiving area.
Solution Approach 2:
The light emitting function is extracted from the light receiving mirror, creating a separate light emitting mirror. This extraction allows the light receiving mirror to have its entire surface available for light reception without needing to reserve any area for light emission, thus maximizing the light receiving area while maintaining reasonable device complexity.
2Device complexity
If a single mirror is used for both laser light emission and reflected light reception, then the structure is simplified, but direct light incident on the emitting region is easily deflected to the light receiving region, deteriorating measurement accuracy
Solution Approach 1:
The optical path is segmented into separate emission and reception paths using distinct mirrors. This segmentation prevents direct light from the emitting region from being deflected to the light receiving region, thereby eliminating the source of measurement error while maintaining a relatively simple overall structure.
Solution Approach 2:
The light emitting function is extracted to a separate mirror positioned such that direct light cannot be deflected to the light receiving mirror. This spatial extraction resolves the interference issue and improves measurement precision without significantly complicating the optical structure.
3Measurement precision
If the light receiving area is increased by using a larger mirror, then the accuracy of position detection is improved, but the driving power required to achieve desired deflection angle increases due to increased air resistance
Solution Approach 1:
The system is segmented into two separate mirrors of appropriate sizes for their respective functions. The light receiving mirror can be larger to capture more light, while the light emitting mirror can be smaller. This segmentation allows optimization of each component's size, enabling large light receiving area for high precision while keeping the overall driving power requirement manageable.
Solution Approach 2:
By changing the configuration from a single large mirror to two separate mirrors with different sizes, the parameters of each mirror can be independently optimized. The light receiving mirror's size is increased to improve detection accuracy, while the separate mounting allows for reduced driving power requirements through optimized rotational mechanics.
4Device complexity
If the second reflecting portion is positioned at the same level as the first reflecting portion, then the structure is simplified, but direct light from the light source can be deflected to the light receiving region, causing interference
Solution Approach 1:
The mounting structure is made asymmetric by positioning the light emitting mirror at a different height than the light receiving mirror. This asymmetric arrangement breaks the symmetry that would allow direct light deflection from the emitting region to the receiving region, thereby eliminating light interference while maintaining reasonable structural complexity.
Solution Approach 2:
The problem is solved by introducing a vertical dimension (height difference) between the two mirrors. Instead of only arranging mirrors side-by-side at the same level, the light emitting mirror is positioned at a different height, creating spatial separation in the vertical dimension that prevents direct light deflection while keeping the horizontal arrangement relatively simple.
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 enhances the accuracy of distance measurement and reduces unnecessary light interference, enabling high accuracy position detection with low driving power and a larger light receiving area.
Implementation Method 1
Laser light from a laser light source is reflected at the light emitting region to perform optical scanning along a scan line
Implementation Method 2
Light emitted to a measurement target is reflected from the measurement target and the reflected light is then incident on the light receiving region
Data Source
Figure 1(A)~1(B)
Figure 2
Figure 3
AI summary
An optical scanning device (1A) includes a support portion including a swingable coupling portion (141, 142) and a frame (11) swingably supporting the coupling portion (141, 142), a first reflecting portion (12) coupled to the coupling portion (141, 142) and configured to swing together with the coupling portion (141, 142), and a swingable connecting portion (15) including a bridge (152) and a second reflecting portion (13) coupled to the first reflecting portion (12) via the bridge (152) and provided at a position away from the first reflecting portion (12) beyond the support portion.