Individually Driven Light Source Array for Imager Parallax Error Reduction
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Solution Overview
Problem
Image capturing devices of imager type readers suffer from parallax error and excessive illumination when the illumination device is not coaxial with the image forming device, leading to inefficient energy use and optical interference between light sources and photosensitive elements.
Innovation Solution
An image capturing device with an array of individually drivable light sources, where the illumination axis is inclined and not coplanar with the reception axis, and a driver adapts the light sources to switch on or off based on the reading distance to ensure only the region framed by the sensor is illuminated, minimizing parallax error and energy waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the illumination device is arranged non-coaxially with the image forming device, then the illumination can cover a wider area, but parallax error occurs and the illumination extends beyond the framed region causing excessive illumination
Solution Approach 1:
The illumination device is divided into multiple independently controllable light sources arranged in an array. Each light source can be individually switched on or off, allowing selective illumination of different regions. This segmentation enables precise control over the illuminated area to match the sensor's field of view, eliminating excessive illumination while maintaining adequate coverage.
Solution Approach 2:
The illumination pattern is made dynamic through individual control of each light source based on reading distance. As the reading distance changes, different subsets of light sources are activated to maintain optimal illumination of the framed region. This dynamic adaptation prevents parallax error by ensuring the illumination axis remains properly aligned with the sensor's viewing axis at all distances.
2Area of stationary object
If all light sources are kept on to ensure complete illumination coverage, then the illuminated area is sufficient, but energy consumption increases
Solution Approach 1:
The array of light sources is divided into independently controllable units. Instead of illuminating the entire array simultaneously, only the necessary subset of light sources is activated based on the current reading distance and sensor field of view requirements. This selective activation maintains sufficient illumination coverage while dramatically reducing energy consumption.
Solution Approach 2:
The illumination parameters (which light sources are active) are dynamically changed based on reading distance. At different distances, different subsets of light sources are switched on or off to maintain optimal illumination of the framed region. This parameter adaptation ensures energy efficiency by activating only the minimum necessary light sources while maintaining adequate illumination coverage.
3Reliability
If the illumination beam is expanded to cover the entire sensor region at all distances, then complete illumination is achieved, but illumination extends beyond the framed region causing waste
Solution Approach 1:
The illumination beam configuration is made dynamic through individual control of each light source. As reading distance varies, the system dynamically adjusts which light sources are active to match the sensor's field of view. This ensures complete illumination of the framed region at all distances without extending illumination beyond the necessary boundaries, thereby preventing energy waste.
Solution Approach 2:
The system uses feedback from reading distance measurement to control light source activation. The reading distance information feeds back to the control logic, which then determines the appropriate subset of light sources to activate. This feedback mechanism ensures that illumination is always precisely matched to the current viewing conditions, maintaining completeness while eliminating waste.
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 solution eliminates parallax error and excessive illumination, enhancing the efficiency and energy usage of the image capturing device while avoiding optical interference, making it suitable for battery-powered portable readers.
Implementation Method 1
an array of individually drivable, adjacent light sources, defining an illumination axis
Implementation Method 2
comprising a sensor in the form of an array - linear or preferably of the matrix type - of photosensitive elements, capable of generating an electric signal from an optical signal
Data Source
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AI summary
An image capturing device (2) of the imager type is described, comprising: - an image forming device (3) including a sensor (4) defining an optical reception axis (Z), at least one reading distance (D, D1, D2), and a region (16, 16-1, 162) framed by the sensor (4) on a substrate (S, Si, S2) at said at least one reading distance (D, D1, D2), - an illumination device (6) including an array (17) of adjacent light sources (18), defining an optical illumination axis (A), characterised: - in that the light sources (18) are individually drivable and each light source (18) is adapted to illuminate an area of a size much smaller than the size of said region (16, 16i, 162) framed by the sensor (4), - in that the illumination axis (A) does not coincide with the reception axis (Z), and - by comprising a driver (13) of the light sources (18) adapted to drive the light sources (18) so as to switch off at least the light sources (18) that illuminate outside of the boundary of the region (16, 16i, 162) framed by the sensor (4) on the substrate (S, S-i, S2) at said at least one reading distance (D, Di, D2).