Code Symbol Reader Concave Case Depth of Field
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Solution Overview
Problem
Conventional code symbol reading apparatuses have limited depth of field, leading to out-of-focus images and reduced resolution, making it difficult to read barcodes outside a specific range, resulting in incomplete barcode reading and operator frustration.
Innovation Solution
A code symbol reading apparatus with a concave front surface and a wide depth of field, allowing the image sensing device to capture barcodes from a broader range, including peripheral positions, by adjusting the lens focal distance and illumination area to ensure optimal image resolution and coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed focus lens is used to reduce cost, then manufacturing cost is reduced, but the depth of field becomes limited and image resolution deteriorates outside the focus position
Solution Approach 1:
The patent changes the focal distance parameter of the lens to a specific value (50mm) that provides an optimal balance between manufacturing simplicity and achieving sufficient depth of field coverage (from 20mm to 80mm from the front surface), resolving the contradiction between cost-effective fixed focus lenses and maintaining image resolution across different object distances
2Adaptability or versatility
If the depth of field is extended to cover peripheral positions, then the reading range is expanded, but the image resolution at the center focus position may deteriorate
Solution Approach 1:
The patent optimizes the focal distance parameter to 50mm, which creates a depth of field extending from 20mm to 80mm from the front surface. This parameter setting allows the system to maintain adequate image resolution both at the center focus position and across peripheral positions, thereby expanding the reading range without sacrificing central focus quality
Solution Approach 2:
The patent introduces a concave portion in the front surface of the case, creating a spatial dimension change that allows the image sensing device to capture barcodes from a broader spatial range including peripheral positions, effectively expanding the reading area without compromising image quality at the center
3Adaptability or versatility
If the lens focal distance is adjusted to increase depth of field, then the reading area is expanded, but the illumination area coverage may become insufficient
Solution Approach 1:
The patent sets the lens focal distance to 50mm, which establishes a depth of field from 20mm to 80mm from the front surface. This parameter configuration is coordinated with the illumination device to ensure that the illumination area adequately covers the expanded depth of field range, resolving the contradiction between increased reading area and sufficient light coverage
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
Enables infallible and easy barcode reading across a wider range, reducing operator effort and increasing reading accuracy by ensuring the lens side limit corresponds with the front surface position, thus allowing barcode analysis even when products are placed close to the apparatus.
Implementation Method 1
a lens to form an image of the image sensing area on the area image sensor with a depth of field so as to the image processing device obtain a resolution to enable analysis of a code symbol included in the image signal
Implementation Method 2
an area image sensor to image-sense the image sensing area through the opening
Implementation Method 3
an illumination device to illuminate the entire image sensing area
Data Source
AI summary
A case has a front surface facing an image sensing area, a concave formed on the front surface, and an opening on the bottom of the concave. The case accommodates an area image sensor to image-sense the image sensing area through the opening, and an illumination device to illuminate the entire image sensing area. There are provided a photoelectric converting unit converting an output of the area image sensor into an electric image signal, and an output unit outputs an image signal converted by the photoelectric converting unit to an image processing device. The case also accommodates a lens to form an image of the image sensing area on the area image sensor with a depth of field so as to the image processing device obtain a resolution to enable analysis of a code symbol included in the image signal. A lens side limit position of the depth of field corresponds with the position of the front surface of the case.