Light Diffusion Unit Pitch for Laser Scanning Display
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Solution Overview
Problem
Scanning-type display devices experience luminance unevenness due to coherent laser light, leading to irregular and regular luminance issues on displayed images.
Innovation Solution
A scanning-type display device is designed with a light source, a condensing unit, an optical scanning unit, and a light diffusion unit with a two-dimensional array of light diffusion channels, where the arrangement pitch of the channels is set based on specific criteria to ensure the condensing size of the laser light is equal to or smaller than the channel pitch, effectively suppressing luminance unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If laser light is used for projection display, then high brightness and color purity are achieved, but luminance unevenness (speckle and regular luminance unevenness) occurs on the displayed image
Solution Approach 1:
The light diffusion unit divides the laser light into multiple beams through a plurality of light diffusion channels arranged in two dimensions. Each channel processes a portion of the coherent light, segmenting the optical path to reduce interference patterns and luminance unevenness while maintaining overall brightness.
Solution Approach 2:
The light diffusion channels are arranged in a two-dimensional array pattern, transforming the one-dimensional laser beam into a two-dimensional light distribution. This dimensional expansion ensures uniform light diffusion across the display area, eliminating speckle and regular luminance unevenness.
2Manufacturing precision
If the arrangement pitch of light diffusion channels is decreased to improve light diffusion uniformity, then luminance unevenness is reduced, but the condensing size of laser light exceeds the channel pitch causing interference
Solution Approach 1:
The invention establishes a specific mathematical relationship between the arrangement pitch P and system parameters (wavelength λ, distance L, effective opening diameter M) given by P≥(4λL)/(πM). This parameter optimization ensures the condensing size matches the channel pitch, preventing light interference while achieving uniform diffusion.
3Speed
If the distance L between optical scanning unit and light diffusion unit is increased to improve scanning accuracy, then high-speed scanning is achieved, but the condensing size increases exceeding the arrangement pitch
Solution Approach 1:
The invention provides a scaling relationship where the arrangement pitch P scales with distance L according to P≥(4λL)/(πM). When distance L increases for high-speed scanning, the arrangement pitch is proportionally increased to maintain the correct condensing size-to-pitch ratio, preventing light overlap and interference.
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 significantly reduces luminance unevenness on displayed images by optimizing the arrangement pitch of the light diffusion channels relative to the wavelength, distance, and effective opening diameter of the optical scanning unit, allowing for high-speed and accurate scanning while maintaining image quality.
Implementation Method 1
a condensing unit which condenses the laser light emitted from the light source
Implementation Method 2
an optical scanning unit which uses the laser light passing through the condensing unit in scanning
Implementation Method 3
a light diffusion unit which includes a plurality of light diffusion channels arranged in two dimensions and diffuses the laser light scanned by the optical scanning unit
Data Source
AI summary
A scanning-type display device includes: a light source which emits projection-display laser light; a condensing unit which condenses the laser light emitted from the light source; an optical scanning unit which uses the laser light passing through the condensing unit in scanning; and a light diffusion unit which includes a plurality of light diffusion channels arranged in two dimensions and diffuses the laser light scanned by the optical scanning unit. When a wavelength of the laser light is denoted by λ, an effective opening diameter of the optical scanning unit is denoted by M, a distance from the optical scanning unit to the light diffusion unit is denoted by L, and an arrangement pitch of the plurality of light diffusion channels is denoted by P, the light diffusion unit is configured so that the arrangement pitch becomes a value set on the basis of P≥(4λL)/(πM).