Linear Magnifying Lens for Contact Image Sensor Resolution
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Solution Overview
Problem
Existing contact image sensors (CIS) face limitations in enhancing scanning resolution without increasing the size and cost of the scanning device, as higher resolution photosensitive chips are costly and enlarging the device with magnifying lenses leads to size and cost issues.
Innovation Solution
The use of two contact image sensors (CIS) with a linear Fresnel magnifying lens between the light-transmitting plate and the lens, allowing for linear magnification in a single direction, enhancing resolution by N times in that direction without enlarging the device, achieved by positioning the linear Fresnel magnifying lens to converge images at the focal point of the lens, enabling the scanning device to capture N rows of pixel points with each movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnifying lens is placed between the scanned object and scanning module to enhance scanning resolution, then the scanning resolution is improved, but the size of the whole scanning device is enlarged
Solution Approach 1:
The patent applies local quality by implementing magnification only in the vertical direction (Y-axis) through a linear magnifying lens, rather than magnifying in all directions. This selective local magnification enhances scanning resolution where needed (vertical pixel separation) while maintaining compact device dimensions in the horizontal direction, thus resolving the contradiction between resolution improvement and device size enlargement.
2Measurement precision
If the resolution of the photosensitive chip is enhanced to improve scanning resolution, then the scanning resolution is improved, but the cost is higher
Solution Approach 1:
The patent introduces a linear magnifying lens as an intermediary optical element between the scanned object and the photosensitive chip. This mediator enlarges the image in the vertical direction before it reaches the chip, allowing the use of a standard-resolution photosensitive chip to achieve high scanning resolution. This approach avoids the need for expensive high-resolution chips while still achieving the desired resolution improvement.
3Measurement precision
If a magnifying lens with magnifying factor of 5 is used to scan a 100mm long object, then the scanning resolution is enhanced, but the minimum size of image plane and scanning module becomes 500mm
Solution Approach 1:
The patent employs a linear magnifying lens that provides magnification only in the vertical direction (Y-axis) with magnifying factor M, while maintaining 1:1 transmission in the horizontal direction (X-axis). This anisotropic magnification approach allows the image plane area to increase only in the vertical dimension (by factor M) rather than in both dimensions (by factor M²), thus significantly reducing the required image plane area while still achieving enhanced scanning resolution.
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 scanning resolution by N times in a single direction, allowing for high-resolution image scanning without increasing the device's size or cost, and can be applied to both X and Y directions, resulting in a more efficient and cost-effective scanning solution.
Implementation Method 1
a linear magnifying lens, wherein the linear magnifying lens is provided between the light-transmitting plate and the lens, and the linear magnifying lens has a characteristic of linearly magnifying an object in a single direction
Implementation Method 2
the linear magnifying lens has a characteristic of linearly magnifying an object in a single direction
Implementation Method 3
positioning the linear Fresnel magnifying lens to converge images at the focal point of the lens
Implementation Method 4
the photosensitive assembly is provided below the lens
Data Source
Figure 1~2a
Figure 2b
Figure 3
AI summary
Some embodiments of the present disclosure provide a Contact Image Sensor (CIS), including a light source, a lens, a light-sensing portion receiving light converged by the lens, a sensor substrate carrying photosensitive Integrated Circuits (IC) arranged linearly, a frame accommodating the lens and the sensor substrate, and a light-transmitting plate provided on an upper part of the frame and configured to carry an original pattern. The CIS further includes a linear magnifying lens, provided between the light-transmitting plate and the lens, the linear magnifying lens having a characteristic of linearly magnifying an object in a single direction. The CIS involved in some embodiments of the present disclosure is capable of enhancing resolution in a single direction.