Image Sensor Substrate Width Reduction via Lead Frame Bending
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Solution Overview
Problem
In contact image sensors, the placement of a rod-shaped light source on both sides of a resin lens plate leads to an enlarged substrate width, increased cost, and degraded image quality due to ghost and stray light issues, as well as out-of-focus problems, which are difficult to address with existing light shielding films and lens arrangements.
Innovation Solution
The solution involves bending the terminals of lead frames toward the substrate center to reduce substrate width, using a metal hood with a slit for improved light transmission and strength, and precise positioning of the slit with respect to the optical axis, along with surface treatments to minimize stray light, and employing compression coils to maintain accurate distance between optics and the original glass plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a rod-shaped light source is provided on both sides of a resin lens plate, then the illuminance on the original is improved, but the substrate width is enlarged and the cost increases
Solution Approach 1:
The patent combines both rod-shaped light sources into a single integrated unit positioned on one side of the lens plate, rather than separating them on both sides. This merging approach maintains the total light output needed for proper illuminance while reducing the overall substrate width and component count, thereby lowering cost without sacrificing illumination quality
Solution Approach 2:
The patent repositions the light source from a two-sided arrangement to a one-sided arrangement with optimized angular positioning. By changing the spatial dimensionality of light source placement and using appropriately angled light sources, the system achieves sufficient illuminance coverage on the original while compacting the substrate footprint
2Object-affected harmful factors
If a light shielding film is formed on the surface of lenses, then ghost and stray light are reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent extracts the light shielding function from a separate film layer and integrates it directly into the lens structure itself. By forming the light shielding portion as an integral part of the lens during the lens manufacturing process, the system effectively blocks ghost and stray light while eliminating the need for separate film application steps, thereby reducing overall manufacturing complexity
Solution Approach 2:
The patent creates a composite lens structure that combines transparent optical material with integrated light shielding portions. This composite design allows the lens to simultaneously perform light transmission and light blocking functions in different regions, effectively preventing stray light without requiring separate shielding films or complex multi-step manufacturing processes
3Volume of moving object
If a rod lens with short focal length is used, then the device size is reduced, but the reading image becomes fuzzy due to out-of-focus degradation
Solution Approach 1:
The patent implements a planar lens array where each individual lens is optimized with specific local characteristics. Each lens in the array has precisely controlled local optical properties including focal length, curvature, and positioning, allowing the system to maintain sharp focus across the entire imaging plane while keeping the overall device compact. The local quality of each lens element compensates for the short focal length constraint
4Ease of manufacture
If through holes are provided at terminal positions of lead frames, then electrical connection is achieved, but the substrate width is enlarged and device size increases
Solution Approach 1:
The patent transitions from a planar two-dimensional arrangement where through holes are positioned at the extreme edges of the substrate to a three-dimensional optimized layout. By routing lead frames and positioning through holes in an optimized spatial configuration that utilizes vertical layering and angular routing, the system achieves reliable electrical connections while significantly reducing the substrate width and overall device footprint
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 results in a compact, cost-effective image sensor with enhanced imaging accuracy, reduced ghost and stray light, and improved positional accuracy of the slit, leading to superior image quality and easier handling of the image sensor device.
Implementation Method 1
a rod-shaped light source (an irradiation device) 101 for irradiating light on an original 104 placed on an original glass plate 108
Implementation Method 2
an imaging optics 102 for focusing light reflected on the original 104
Implementation Method 3
a light-receiving element 103 for receiving light passing through the imaging optics 102
Implementation Method 4
a metal hood 107 provided with a slit 106 for passing the light reflected on the original 104
Data Source
AI summary
There is provided an image sensor in which an enlargement of a substrate width is not caused even in a case that a rod-shaped light source is provided on both sides of a resin lens plate, respectively, and in which a positional accuracy of component is superior. The image sensor comprises a rod-shaped light source for irradiating light to an original placed on an original glass plate, an imaging optics for focusing light reflected on the original, and a light-receiving element for receiving light passing through the imaging optics, the light-receiving element being positioned at a predetermined location on a substrate which is provided with through holes for terminals of lead frames of the rod-shaped light source. The terminals of lead frames of the rod-shaped light source are bent toward the center of the substrate to be connected with the through holes.