LED Module with Zener Diodes for Compact Image Sensor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image sensor modules for document scanners face challenges in size reduction due to the large size of LED modules and the need to maintain mechanical strength, particularly in the thickness direction, which limits the miniaturization of document scanners.
Innovation Solution
The design incorporates an LED module with a specific arrangement of LED chips and Zener diodes, bonded via insulating and conductive layers, and a light guide with reflective surfaces to emit linear light, along with mirrors and a lens unit to extend the light path without increasing the module's thickness, allowing for a compact and mechanically strong image sensor module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the LED module size is reduced to miniaturize the document scanner, then the overall device size decreases, but the mechanical strength particularly in the thickness direction is compromised
Solution Approach 1:
The patent embeds the LED module within a recessed region of the housing, creating a nested structure where the LED module is positioned inside a designated space. This nesting approach reduces the overall protrusion and volume of the document scanner while maintaining structural integrity through the housing's integrated design.
Solution Approach 2:
The patent extends the light guide in the thickness direction (z-axis) to create a longer light path without increasing the footprint area. By utilizing the thickness dimension, the design achieves compactness in the planar dimensions while maintaining adequate light path length for scanning functionality.
2Measurement precision
If the light path length is increased to improve image quality when the read object has folds or wrinkles, then image clarity improves, but the module thickness increases
Solution Approach 1:
The patent utilizes the thickness direction (z-axis) to extend the light path length by configuring the light guide to propagate light over a longer distance in the vertical dimension rather than increasing the horizontal footprint. This allows adequate light path length for imaging folded objects without increasing overall module thickness.
Solution Approach 2:
The patent incorporates a reflective surface with a curved cross-section (arcuate shape) within the light guide to redirect light paths. This curved reflection geometry extends the effective light path length while containing the light guide within a compact thickness envelope, improving image quality without proportionally increasing module thickness.
3Area of stationary object
If LED chips are densely arranged to reduce module size, then the LED module footprint decreases, but it becomes difficult to arrange bonding layers and wires
Solution Approach 1:
The patent divides the LED chip array into multiple rows and columns with systematic spacing, creating discrete bonding locations for each LED chip. This segmented arrangement provides dedicated wire bonding paths and bonding layer spaces for each chip, making the manufacturing process manageable despite high density.
Solution Approach 2:
The patent provides localized bonding regions and wire routing spaces adjacent to each LED chip position, ensuring that each chip has adequate access for bonding operations. This local quality approach maintains manufacturing feasibility by ensuring each chip location has the necessary clearance for bonding layers and wires, even in a densely packed overall arrangement.
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 enables a reduction in the size and thickness of the image sensor module while maintaining mechanical strength, facilitating the miniaturization of document scanners and improving their operational efficiency.
Implementation Method 1
The light guide 94 guides the light emitted from the LED module 93 toward the read object 890 and is made of transparent resin. The light guide 94 is elongated in the primary scanning direction and includes an incident surface (not shown), a reflective surface 94a, and an emission surface 94b. The reflective surface 94a reflects the light traveling from the incident surface.
Implementation Method 2
The reflective surface 94a reflects the light traveling from the incident surface.
Implementation Method 3
The reflected light is converged onto the sensor IC 96 by the lens unit 95.
Data Source
AI summary
An LED module includes first through third LED chips and two Zener diodes for preventing excessive voltage application to the first and the second LED chips. A first lead includes a mount portion on which the first through third LED chips and the two Zener diodes are mounted. A resin package covers part of the first lead and includes an opening for exposing the three LED chips and two Zener diodes. A single insulating layer bonds the first and second LED chips to the first lead. A single conductive layer bonds the third LED chip and two Zener diodes to the first lead. The Zener diodes are arranged between the first, second LED chips and the third LED chip.