Multi-Image Projector With Diffractive Optical Elements
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Solution Overview
Problem
Conventional projectors with fixed focal lengths and fields of view struggle to maintain resolution when projecting patterns onto objects at varying distances, leading to inaccurate depth information in 3D imaging systems.
Innovation Solution
A projector design incorporating a laser module and a lens module with multiple lenses and diffractive optical elements, where the laser diodes generate collimated laser beams that are processed by lenses with different focal lengths to create overlapping images, allowing for adaptive projection based on working distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional projector with fixed focal length is used, then the device complexity is low, but the manufacturing precision of the projected pattern deteriorates when the object distance varies
Solution Approach 1:
The patent divides the single lens into multiple lenses with different focal lengths (e.g., first lens with focal length f1, second lens with focal length f2). Each lens is designed to project patterns for specific distance ranges, allowing the system to maintain high resolution across varying object distances by selecting the appropriate lens segment for the current working condition.
Solution Approach 2:
The patent implements a dynamic switching mechanism that adjusts which lens is active based on the detected object distance. The controller dynamically selects the appropriate lens (first lens for far distances, second lens for close distances) to ensure optimal pattern resolution, making the projector adaptable rather than static.
2Area of stationary object
If a single lens with fixed field of view is used, then the device complexity is low, but the area of the projected image deteriorates when the object distance changes
Solution Approach 1:
The patent segments the field of view coverage by assigning different lenses to different distance ranges. The first lens provides a first field of view for far-distance projection, while the second lens provides a second field of view for close-distance projection, ensuring adequate coverage area regardless of object distance.
Solution Approach 2:
The patent creates a multi-functional lens module where each lens serves multiple purposes: the first lens handles far-distance projection with appropriate FOV, the second lens handles close-distance projection with different FOV, and together they provide universal coverage for all working distances.
3Measurement precision
If the projector uses a fixed focal length lens, then the ease of manufacture is high, but the measurement precision of depth information deteriorates at varying distances
Solution Approach 1:
The patent segments the depth measurement capability by using multiple lenses with different focal lengths optimized for different distance ranges. This segmentation allows each lens to provide high-precision depth information for its designated range, improving overall measurement precision across all distances.
Solution Approach 2:
The patent implements a feedback mechanism where the controller detects the object distance and automatically selects the appropriate lens to ensure accurate depth measurement. This closed-loop control ensures that the system always uses the optimal lens for the current working distance, maintaining high measurement precision.
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 design enhances the resolution and field of view of projected images, enabling accurate depth information capture regardless of object distance, by selectively using lenses with appropriate focal lengths for clear image generation.
Implementation Method 1
the laser module includes a plurality of laser diodes, the laser diodes are arranged to generate a plurality laser beams
Implementation Method 2
each of the lenses is arranged to receive one of the at least one laser beam to generate a collimated laser beam
Implementation Method 3
the diffractive optical elements correspond to the lenses, respectively, and each of the diffractive optical elements is arranged to receive the collimated laser beam from the corresponding lens to generate an image
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
The present invention provides a projector (110) including a laser module (210) and a lens module (220), wherein the lens module (220) includes a plurality of lenses (222_1 , 222_2) and a plurality of diffractive optical elements (224_1, 224_2). In the operations of the projector (110), the laser module (210) is arranged to generate at least one laser beam; each of the lenses (222_1, 222_2) is arranged to receive one of the at least one laser beam to generate a collimated laser beam; and the diffractive optical elements (224_1, 224_2) correspond to the lenses (222_1, 222_2), respectively, and each of the diffractive optical elements (224_1, 224_2) is arranged to receive the collimated laser beam from the corresponding lens (222_1, 222_2) to generate an image. The images generated by the diffractive optical elements (224_1, 224_2) form a projected image of the projector (110). By using the projector (110) of the present invention, the projected image may have higher resolution or field of view that is advantageous for the 3D sensing system.