Image Reading Device Light Guide Lens Array Illumination
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Solution Overview
Problem
Existing image reading devices face inefficiencies in illuminating objects to form clear erect equal-magnification images, as they require precise band-like illumination that is challenging to achieve with conventional techniques.
Innovation Solution
An image reading device with a novel illumination unit featuring a light guide body and a lens array, where the light guide body guides light from a light source to the object and the lens array condenses reflected light to form an erect equal-magnification image on a sensor, utilizing a specific configuration of frames and light shielding films to enhance illumination efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional illumination unit is used, then the structure is simple, but the illumination efficiency and band-like illumination capability are insufficient
Solution Approach 1:
A light guide body is introduced as an intermediary component between the light source and the object to be read. The light guide body receives light from the light source and guides it to the illumination position, enabling efficient band-like illumination while maintaining a relatively simple overall structure. The light guide body acts as a mediator that optimizes light distribution without requiring complex illumination unit design.
2Volume of moving object
If the light guide body and lens array are positioned close to each other, then the device size is reduced, but light may leak to the sensor
Solution Approach 1:
A light shielding film is applied locally at the bottom surface of the light guide body to prevent light leakage in the specific region where the lens array is positioned. This localized shielding approach allows the light guide body and lens array to be positioned close together for compact device size, while the light shielding film selectively blocks light in the critical area where leakage would affect the sensor, without obstructing the illumination function.
3Manufacturing precision
If the illumination unit is designed for high-efficiency band-like illumination, then image formation quality is improved, but the device complexity increases
Solution Approach 1:
The illumination function is segmented into distinct components: a light source, a light guide body with specific geometric features (chamfered surfaces, light shielding film), and a lens array. This segmentation allows each component to be optimized for its specific function while maintaining overall system simplicity. The light guide body's segmented structure with chamfered surfaces and light shielding film enables precise band-like illumination control without requiring a completely complex illumination unit design.
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 device achieves high-efficiency band-like illumination of the object, ensuring effective formation of erect equal-magnification images by optimizing the placement and chamfering of the light guide and lens array, thereby improving light utilization and preventing light leakage to the sensor.
Implementation Method 1
a light guide body guiding light of a light source that is facing one longitudinal end surface of the light guide body to an object to be read
Implementation Method 2
an image forming optical device that is disposed parallel to the light guide body, has a lens array provided with an incidence surface in which a plurality of lens surfaces are arranged in the longitudinal direction of the light guide body, and condenses reflected light from the object which is incident on the incidence surface, thereby forming an erect equal-magnification image on a sensor
Data Source
AI summary
An image reading device including an illumination unit that has a light guide body guiding light of a light source that is facing one longitudinal end surface of the light guide body to an object to be read; and an image forming optical device that is parallel to the light guide body, has a lens array with an incidence surface in which lens surfaces are arranged in the longitudinal direction of the light guide body, and condenses reflected light from the object which is incident on the incidence surface, thereby forming an erect equal-magnification image on a sensor. The image reading device further includes a frame on which is disposed the image forming optical device. A second frame projects in a direction away from the first frame and connects to the first frame, or the frame connects to an H-shaped cross-section frame.