On-the-Fly Reflection Vector Circuit for Projectors
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Solution Overview
Problem
Existing projectors employing oscillating mirrors for scanning light beams face challenges in accurately and efficiently determining the pixel to be projected due to elaborate and power-consuming tasks in simulating or measuring the light path, requiring large memory for pixel sequences, and inability to compensate for mirror oscillation fluctuations.
Innovation Solution
An electric circuit with dedicated hardware, comprising a projection and summation sub-circuit, computes the reflection vector of the light beam on-the-fly using mirror normal and incidence vectors, allowing for fast and accurate synchronization of the mirror and light source without the need for intricate predetermination and storage of pixel sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If simulation or measurement of light path is performed in CPU, then pixel sequence can be determined, but computation time and power consumption increase
Solution Approach 1:
The patent replaces the mechanical/computational system (CPU-based simulation or measurement) with an optical system. The light path determination is performed optically using a reference light beam that follows the same path as the projection light beam, eliminating the need for time-consuming CPU calculations while maintaining accuracy.
Solution Approach 2:
The patent creates an optical copy of the light path by introducing a reference light beam that travels through the same optical components (oscillating mirror, projection optics) as the projection light beam. This optical copy allows direct determination of the pixel sequence without computational simulation.
2Extent of automation
If pixel sequence is stored in memory, then synchronization is enabled, but memory size and access time are constrained
Solution Approach 1:
Instead of storing pixel sequences in digital memory, the patent creates an optical copy of the scan pattern using a reference light beam. The spatial and temporal characteristics of this optical copy directly provide the synchronization information needed, eliminating the requirement for large digital memory storage.
Solution Approach 2:
The patent extracts only the essential synchronization information (the pixel sequence corresponding to the scan pattern) from the complete light path determination process. This extracted information is obtained optically rather than being stored digitally, reducing memory requirements while maintaining synchronization capability.
3Device complexity
If fixed pixel sequence is used, then synchronization is simplified, but adaptation to mirror oscillation changes is lost
Solution Approach 1:
The patent transitions from a static, fixed pixel sequence to a dynamic determination process. The reference light beam continuously follows the actual oscillation of the mirror in real-time, automatically adapting to any changes in mirror oscillation characteristics without requiring complex reprogramming or recalculation.
Solution Approach 2:
The reference light beam acts as a feedback mechanism that continuously monitors the actual mirror oscillation and automatically adjusts the determined pixel sequence accordingly. This feedback loop ensures that the system adapts to mirror oscillation changes without increasing synchronization 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
This approach enhances frame rate and image resolution by reducing memory requirements and compensating for mirror oscillation fluctuations, while being energy-efficient and compact.
Implementation Method 1
compute a dot product of said mirror normal vector and said incidence vector from the obtained coordinates
Implementation Method 2
compute each coordinate of a projection vector as a product of the respective coordinate of the mirror normal vector and said dot product times minus two
Implementation Method 3
add the computed projection vector to the incidence vector to determine the reflection vector of the light beam
Implementation Method 4
The mirror, e.g., a micro-electromechanical-system (MEMS) mirror or a galvo mirror, oscillates about two axes to reflect the light beam into subsequent directions
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
An electric circuit (12) determines a reflection vector (r) of a light beam (4) incident on and reflected by an oscillating mirror (7), and comprises an input (14) configured to obtain coordinates (nx, ny, nz, ix, iy, iz) of a mirror normal vector (n) of the oscillating mirror and of an incidence vector (i) of the incident light beam (4) in a common three-dimensional coordinate system (21); a projection sub-circuit (22) configured to compute a dot product (n·i) of said mirror normal vector and said incidence vector from the obtained coordinates, and each coordinate (px, py, pz) of a projection vector (p) as a product of the respective coordinate of the mirror normal vector and said dot product times minus two; and a summation sub-circuit (27) configured to add the computed projection vector to the incidence vector to determine the reflection vector. A projector (1) utilises the electric circuit to control a light source (6) emitting said light beam.