Tapered Lens Assembly for Wide-Angle Ambient Light Sensing
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Solution Overview
Problem
Ambient light sensors face challenges in responding effectively to light from a wide range of angles due to errors when light impacts the sensor surface at large angles, limiting their ability to provide accurate brightness control and energy conservation in handheld devices.
Innovation Solution
A compact optoelectronic package featuring a tapered lens assembly with an opaque encasement and a carrier with electric interconnections, where the lens is formed from a transparent material with a smaller refractive index than the encasement, enabling total internal reflection and a wide field of view by directing incident radiation onto the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional lens is used with a housing aperture, then the structure is simple, but the field of view is limited and light from large angles causes sensor errors
Solution Approach 1:
The patent employs a lens with a curved lateral surface instead of a conventional planar or simple spherical shape. The curved surface is specifically designed to redirect light rays entering at large angles toward the sensor, expanding the effective field of view while maintaining optical accuracy. This curvature transformation resolves the contradiction by enabling wide-angle light collection without requiring a complex multi-element lens system.
Solution Approach 2:
The invention extends the optical functionality into the lateral dimension by designing a lens where the lateral surface curvature actively participates in light redirection. Rather than relying solely on the front surface curvature, the lateral surface is shaped to guide oblique light rays toward the sensor, effectively adding a dimensional element to light control that expands the field of view without proportionally increasing device complexity.
2Volume of moving object
If the lens width decreases to a non-vanishing minimal width at the upper surface, then the package size is reduced, but the visible aperture becomes larger
Solution Approach 1:
The lens exhibits asymmetric geometry where the lateral surface tapers from a maximal width at the bottom surface to a non-vanishing minimal width at the upper surface. This asymmetric tapering allows the package height to be minimized while the aperture area at the top surface is optimized for light collection. The non-vanishing minimal width specifically enables the aperture to remain visible and functional while the overall package volume is reduced through the tapered profile.
Solution Approach 2:
The lens design pre-configures the light path by shaping the lateral surface to redirect oblique light rays before they reach the sensor plane. This preliminary redirection action allows the use of a smaller, more compact lens structure that would otherwise be insufficient for wide-angle light collection, thereby reducing package size while maintaining effective aperture functionality.
3Measurement precision
If a tapered lens with curved lateral surface is used, then light from wide angles is directed accurately onto the sensor, but manufacturing complexity increases
Solution Approach 1:
The patent specifies particular parameter ranges for the lens geometry, including the curvature radius of the lateral surface and the tapering profile from maximal to minimal width. By optimizing these parameters within specific ranges, the design achieves accurate light redirection for wide-angle inputs while maintaining manufacturability. The parameter optimization balances optical performance with fabrication ease, resolving the contradiction between precision and manufacturing complexity.
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 enhances the accuracy and efficiency of ambient light sensors by enlarging their field of view while maintaining a compact package size, reducing the visible aperture, and minimizing manufacturing costs through a molding-based production method.
Implementation Method 1
The lens is formed from a transparent material with a smaller refractive index than the encasement, enabling total internal reflection
Implementation Method 2
the lens is arranged between the optoelectronic component and the aperture... widths of the lens are defined in this lateral direction by the lateral surface. These widths decrease in the vertical direction
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The lens assembly comprises a lens or lens-shaped region (1) having an upper surface (11), a lateral surface (12) surrounding the lens or lens-shaped region, and a bottom surface (13). An optoelectronic component (2) is arranged at or near the bottom surface, and an aperture (3) is arranged at the upper surface, so that the lens is arranged between the optoelectronic component and the aperture. Widths (w1, w2) of the lens that are defined in a specified lateral direction decrease from a maximal width at or near the bottom surface to a non-vanishing minimal width at the upper surface. In particular, the entire lens may be tapered.