Optical Element With Secondary Beam Splitter for Goggle Displays
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Solution Overview
Problem
Goggle type displays experience luminous flux dropouts due to limited light size, leading to shadowed regions, and increasing light guide size results in manufacturing difficulties and increased weight.
Innovation Solution
Incorporating a secondary substrate with a beam splitter surface in front of the main light guide to split and magnify light, preventing dropouts without increasing size or weight, and improving productivity by reducing complex processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light guide size is increased to prevent luminous flux dropouts, then the brightness uniformity is improved, but the device weight and manufacturing complexity increase
Solution Approach 1:
The light guide is divided into a main substrate and a secondary substrate with different functions. The main substrate handles primary light guidance while the secondary substrate addresses luminous flux distribution, allowing each component to be optimized independently for weight and performance
Solution Approach 2:
A secondary beam splitter surface is added in front of the main beam splitter surface, creating a new optical dimension. This additional surface enables light splitting and magnification without increasing the overall device volume, preventing dropouts while maintaining compact size
2Illumination intensity
If the light guide size is increased to prevent luminous flux dropouts, then the brightness uniformity is improved, but the manufacturing complexity increases
Solution Approach 1:
The light guide is divided into a main substrate and a secondary substrate with different functions. The main substrate handles primary light guidance while the secondary substrate addresses luminous flux distribution, allowing each component to be optimized independently for weight and performance
Solution Approach 2:
A secondary beam splitter surface is added in front of the main beam splitter surface, creating a new optical dimension. This additional surface enables light splitting and magnification without increasing the overall device volume, preventing dropouts while maintaining compact size
3Illumination intensity
If the light guide size is increased to prevent luminous flux dropouts, then the brightness uniformity is improved, but the productivity decreases
Solution Approach 1:
The light guide is divided into a main substrate and a secondary substrate with different functions. The main substrate handles primary light guidance while the secondary substrate addresses luminous flux distribution, allowing each component to be optimized independently for weight and performance
4Weight of moving object
If the light guide size is limited to maintain compact device, then the device weight is reduced, but luminous flux dropouts occur
Solution Approach 1:
A secondary beam splitter surface is added in front of the main beam splitter surface, creating a new optical dimension. This additional surface enables light splitting and magnification without increasing the overall device volume, preventing dropouts while maintaining compact size
Solution Approach 2:
The refractive index of the secondary substrate is specifically designed to differ from the main substrate (e.g., air gap or different material). This parameter change enables the secondary substrate to function as an additional beam splitter, magnifying luminous flux and preventing dropouts without increasing device size
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
Prevents luminous flux dropouts, allows for a smaller and lighter display device with uniform brightness, and enhances manufacturing efficiency by avoiding protrusions and complex processing.
Implementation Method 1
The beam splitter surface 11 comprises three planar beam splitter surfaces, arranged in the X direction in the sequence: first beam splitter surface 11a, second beam splitter surface 11b, third beam splitter surface 11c. Furthermore, each of the beam splitter surfaces 11a through 11c are arranged at the same angle β to the X direction when viewed from the Z direction. The first beam splitter surface 11a, second beam splitter surface 11b and third beam splitter surface 11c furthermore make it possible to reflect a predetermined fraction of the luminous flux of the inputted image display light L and to transmit a predetermined fraction of the luminous flux of the image display light L.
Implementation Method 2
Light guide 10 is a substrate fashioned from a light transmitting material such as glass (BK7, etc.), resin (polycarbonate, polymethacrylic acid (PMMA), cycloolefin, etc.)
Data Source
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AI summary
In order to provide an optical element in which the occurrence of a region where no light beams are present (omission) is prevented, an optical element 100 is provided with a main substrate 10 which is manufactured from a light-transmitting material and in which a front surface 10a and a rear surface 10b are parallel to the setting directions, wherein at least one main beam splitter surface 11 is provided obliquely to the setting directions and formed inside the primary substrate 10. The optical element 100 is also provided with a sub substrate 20 which is manufactured from a light transmitting material and in which a front surface 20a and a rear surface 20b are parallel to the setting directions, wherein a sub beam splitter surface 30 is arranged at least between the front surface 20a or the rear surface 20b of the single sub substrate 20, and the rear surface 10b or the front surface 10a of the main substrate 10.