Image Reading Device Lens Holder Positioning
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Solution Overview
Problem
Existing image reading devices face issues in maintaining the accurate relative positional relationship between light guides and optical filters, leading to image quality deterioration due to variance in positions and adhesive flow into the light path.
Innovation Solution
The image reading device employs a lens holder with positioners to accurately position light guides and optical filters, and includes excess adhesive escape mechanisms to prevent adhesive flow into the light path, ensuring precise alignment and high-quality imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical filters are bonded to light guide holders using adhesive, then the optical filters can be fixed in position, but adhesive may intrude into the light path causing image quality deterioration
Solution Approach 1:
The bonding surface is segmented into two distinct regions: a light shielding region that prevents adhesive from entering the light path, and a non-light shielding region that allows adhesive application. This segmentation resolves the contradiction by allowing reliable bonding while preventing harmful adhesive intrusion into the optical path.
Solution Approach 2:
Different regions of the bonding surface are given different properties: the light shielding region has light-blocking characteristics to protect the optical path, while the non-light shielding region allows adhesive penetration. This local differentiation enables the bonding surface to simultaneously achieve secure fixation and prevent adhesive contamination of the light path.
2Ease of manufacture
If the relative positional relationship between light guides and optical filters is not highly accurate, then manufacturing is simpler, but image quality deteriorates due to position variance
Solution Approach 1:
Positioning protrusions and recesses are designed into the light guide holder and optical filter components before assembly. These pre-formed positioning features guide the components into their correct relative positions during assembly, eliminating the need for complex post-assembly adjustments and ensuring high positioning accuracy without complicating the manufacturing process.
3Object-affected harmful factors
If adhesive reservoir groove is disposed in bonding portion, then adhesive intrusion into light path is prevented, but adhesive may still squeeze out from the groove causing image quality deterioration
Solution Approach 1:
The bonding surface is divided into a light shielding region and a non-light shielding region. The light shielding region acts as a barrier that prevents adhesive from reaching the light path, while the non-light shielding region accommodates adhesive application. This segmentation effectively addresses both issues: preventing intrusion into the light path and controlling adhesive placement to avoid squeezing out.
4Volume of moving object
If optical filters are made smaller to reduce device size, then device compactness is improved, but positioning accuracy between light guides and optical filters becomes more difficult to maintain
Solution Approach 1:
Positioning protrusions and recesses are pre-formed on the optical filter and light guide holder components. These positioning features are designed to work effectively even with smaller optical filter dimensions, ensuring that compactness is achieved without compromising positioning accuracy. The preliminary positioning structures guide the small optical filters into precise alignment with the light guides during assembly.
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 maintains a high-accuracy relative positional relationship between light guides and optical filters, preventing adhesive intrusion and enhancing image quality while reducing the size of optical filters and the device itself.
Implementation Method 1
a light guide extending in a main scanning direction and configured to emit light from a light source toward a reading target moving relatively in a sub-scanning direction, the light from the light source being projected into an end surface of the light guide in the main scanning direction
Implementation Method 2
an optical filter arranged between the light source and the end surface of the light guide in the main scanning direction and configured to block or attenuate light having a specific wavelength from the light from the light source
Implementation Method 3
a lens body to focus reflected light reflected by the reading target onto a light receiver to convert the reflected light into an electrical signal
Data Source
AI summary
An image reading device includes (i) light guides extending in a main scanning direction and configured to emit light from a light source toward a reading target moving relatively in a sub-scanning direction, the light from the light source being projected into end surfaces of the light guides in the main scanning direction, (ii) an optical filter arranged between the light source and the end surfaces of the light guides and configured to block or attenuate light having a specific wavelength from the light from the light source, (iii) a lens body to focus reflected light reflected by the reading target onto a light receiver to convert the reflected light into an electrical signal, and (iv) a lens holder. The lens holder includes a first positioner for positioning the light guides and a second positioner for positioning the optical filter.