Vertical Optical Sensor with Time-Division Switching
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Solution Overview
Problem
Optical sensor devices with independently formed photo diodes on a semiconductor substrate face issues with uneven light distribution due to incident angles, leading to deviations in output ratios and deteriorated optical directivity characteristics.
Innovation Solution
The integration of multiple light receiving units with different spectral sensitivity characteristics in a vertical structure, coupled with a switch unit that selects outputs in a time-division manner to adjust light receiving characteristics, ensures even light distribution and accurate detection of illumination intensity without the need for optical filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two types of photo diodes are independently formed on a semiconductor substrate, then the device can detect different spectral characteristics, but light distribution becomes uneven due to incident angles causing deviation in output ratios and deteriorating optical directivity characteristics
Solution Approach 1:
The patent combines multiple light receiving units with different spectral sensitivity characteristics into a single integrated structure. The first light receiving unit includes a first photo diode and a second photo diode, while the second light receiving unit includes a third photo diode and a fourth photo diode. These units are vertically stacked and share common electrodes, merging their functions to achieve both spectral detection capability and improved optical directivity characteristics by ensuring even light distribution across all photo diodes.
Solution Approach 2:
The patent transitions from a planar arrangement of photo diodes to a vertical stacked structure. By arranging light receiving units in the vertical dimension with multiple photo diodes stacked along the light receiving direction, the patent achieves both spectral differentiation and uniform light distribution. The vertical integration allows light to pass through multiple photo diodes sequentially, ensuring each receives adequate illumination regardless of incident angle.
2Measurement precision
If multiple light receiving units with different spectral sensitivity are integrated in a vertical structure, then optical directivity characteristics improve, but device complexity increases due to the need for switch units and time-division multiplexing
Solution Approach 1:
The patent employs time-division multiplexing with periodic switching between different light receiving units. The switch unit alternates between selecting the first light receiving unit and the second light receiving unit in periodic time slots. This periodic action allows the system to sequentially detect signals from different photo diodes with different spectral sensitivities, achieving precise optical directivity measurement while managing device complexity through systematic temporal separation of detection functions.
Solution Approach 2:
The switch unit serves multiple functions: it selects between different light receiving units, manages time-division multiplexing of detection signals, and coordinates the periodic switching between units with different spectral sensitivities. This multi-functional design consolidates control operations into a single component, reducing overall device complexity while maintaining the ability to achieve precise optical directivity characteristics through integrated control.
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 enhances optical directivity characteristics by maintaining consistent output ratios across light receiving units, even when light does not evenly reach both units, thereby improving the precision of illumination intensity measurement.
Implementation Method 1
measures intensity of light made incident on each of two types of photo diodes 401 and 402 having different light receiving characteristics (spectral sensitivity characteristics)
Data Source
AI summary
An optical sensor device includes at least two light receiving units in which a plurality of types of light receiving elements is integrated in the same vertical structure. In addition, the optical sensor device further includes a switch unit configured to select at least one of the light receiving elements in each of the light receiving units in a time-division manner.