Ring-Shaped Light Guide for Uniform Illumination in Biometric Sensors
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Solution Overview
Problem
Conventional image capturing apparatuses for biometric authentication face challenges in miniaturization and cost reduction due to the need for separate printed circuit boards for light-emitting devices and photoelectric conversion sensors, which also restricts uniform illumination of the object.
Innovation Solution
An image capturing apparatus with a ring-shaped light guide member and light-emitting devices mounted on a single circuit board, along with a photodetector device and distance-measuring light-emitting devices, to achieve miniaturization and uniform illumination, allowing the optical unit to be housed inside the ring-shaped light guide member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light-emitting devices and photoelectric conversion sensors are mounted on separate printed circuit boards, then uniform illumination of the object can be achieved, but the apparatus size increases and manufacturing cost increases
Solution Approach 1:
The patent combines light-emitting devices and photoelectric conversion sensors onto a single printed circuit board, eliminating the need for separate boards. This integration reduces the overall apparatus volume while maintaining uniform illumination capability through careful arrangement of the light guide member and optical elements.
Solution Approach 2:
The patent houses the optical unit inside the ring-shaped light guide member, creating a nested structure where one component is contained within another. This nesting approach maximizes space utilization and reduces the apparatus footprint while preserving the uniform illumination function.
2Illumination intensity
If light-emitting devices and photoelectric conversion sensors are mounted on separate printed circuit boards, then uniform illumination of the object can be achieved, but manufacturing cost increases
Solution Approach 1:
The patent combines light-emitting devices and photoelectric conversion sensors onto a single printed circuit board, eliminating the need for separate boards. This integration reduces the overall apparatus volume while maintaining uniform illumination capability through careful arrangement of the light guide member and optical elements.
Solution Approach 2:
The single printed circuit board serves multiple functions: mounting light-emitting devices, mounting photoelectric conversion sensors, and providing structural support for the optical system. This multi-functionality reduces component count and manufacturing complexity.
3Illumination intensity
If multiple point light sources are disposed apart from each other to share a predetermined image capturing range, then uniform illumination can be achieved, but the apparatus cannot be miniaturized
Solution Approach 1:
The patent houses the optical unit inside the ring-shaped light guide member, creating a nested structure where one component is contained within another. This nesting approach maximizes space utilization and reduces the apparatus footprint while preserving the uniform illumination function.
Solution Approach 2:
The patent transitions from a planar arrangement of light sources to a three-dimensional structure using a ring-shaped light guide member. This dimensional change allows light to be distributed uniformly across the image capturing range while maintaining a compact apparatus volume.
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 the miniaturization of the apparatus, reduces costs by eliminating the need for separate circuit boards, and provides uniform illumination for effective biometric authentication.
Implementation Method 1
a ring-shaped light guide member for guiding the light emitted from the plurality of light-emitting devices, and illuminating the image capturing range
Implementation Method 2
an optical unit housed inside the ring of the ring-shaped light guide member, guiding the reflected light from the illuminated object in the image capturing range to the image sensor
Implementation Method 3
a circuit board for mounting an image sensor for receiving the reflected light
Data Source
AI summary
An image capturing apparatus illuminates an object and captures an image of the object using the reflected light from the object. On a circuit substrate mounted an image sensor, a plurality of light-emitting devices are mounted in the peripheral positions of the image sensor. By means of a ring-shaped light guide member, the light from the plurality of light-emitting devices is guided to an image capturing range, so as to illuminate the object. With this, by mounting a light receiving system and a light emitting system on an identical substrate, miniaturization can be achieved, and the image capturing range can be illuminated by substantially uniform light. Also, using the ring-shaped light guide member, an optical unit is housed inside the ring, thus enabling further miniaturization.