Projector Light Source Layout for Speckle Reduction
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Solution Overview
Problem
Existing light source devices using reflective diffusion plates struggle with increased speckle noise due to limited diffusion angles and require large collimator lenses, which increase device size.
Innovation Solution
A light source device design that includes a reflective diffusion plate with a first collimator lens positioned adjacent to the diffusion plate, allowing perpendicular incidence of laser beams and increased diffusion angles, thereby separating incident and reflected light effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the collimator lens is positioned remote from the reflective diffusion plate, then the device structure is simpler, but the collimator lens size increases and speckle noise reduction is insufficient
Solution Approach 1:
The patent introduces a first reflection plate with a through-hole to create a new optical path dimension. The first laser beam passes through the through-hole and is reflected by the reflection plate to enter the reflective diffusion plate perpendicularly, while the diffused light takes a different path through the collimator lens. This dimensional change in light path allows the collimator lens to be positioned adjacent to the reflective diffusion plate without requiring remote positioning, thus reducing lens size while maintaining structural simplicity.
Solution Approach 2:
The first reflection plate acts as an intermediary component that mediates between the first laser beam and the reflective diffusion plate. It redirects the laser beam perpendicularly onto the diffusion plate surface, enabling compact positioning of the collimator lens while achieving effective speckle noise reduction through increased diffusion angle.
2Device complexity
If the collimator lens is positioned remote from the reflective diffusion plate, then the device structure is simpler, but the diffusion angle cannot be increased
Solution Approach 1:
By introducing the first reflection plate with through-hole, the patent creates a new spatial arrangement that allows perpendicular incidence of the laser beam onto the reflective diffusion plate. This dimensional change in the optical path enables the collimator lens to be positioned very close to the diffusion plate, thereby maximizing the diffusion angle of the scattered light without complicating the overall device structure.
3Ease of operation
If the laser beam is incident obliquely to the reflective diffusion plate, then the incident and reflected light can be separated, but the collimator lens size increases
Solution Approach 1:
Instead of using oblique incidence to separate incident and reflected light, the patent inverts the approach by using perpendicular incidence combined with a first reflection plate. The laser beam is redirected perpendicularly onto the diffusion plate, and the reflection plate's through-hole configuration naturally separates the incident beam path from the reflected diffused light path, achieving light separation without requiring large collimator lens positioning.
4Volume of moving object
If the laser beam is incident perpendicularly to the reflective diffusion plate, then the collimator lens size is minimized, but incident and reflected light separation becomes difficult
Solution Approach 1:
The first reflection plate serves as an intermediary that resolves the light separation issue. By positioning the reflection plate with its through-hole between the laser source and the reflective diffusion plate, it creates distinct optical paths: the incident laser beam passes through the through-hole to hit the diffusion plate perpendicularly, while the reflected diffused light is directed through the collimator lens. This intermediary component enables perpendicular incidence without complicating the light separation mechanism.
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 reduces speckle noise significantly while minimizing the size of the collimator lens and overall device.
Implementation Method 1
a first collimator lens that is provided between the first reflection plate and the reflective diffusion plate. The first laser beam passes through the through-hole and the first collimator lens in that order and enters the reflective diffusion plate, and diffused light, which is reflected light emitted from the reflective diffusion plate, passes through the first collimator lens and enters the first reflection plate. The first collimator lens condenses the first laser beam on the reflective diffusion plate and collimates the diffused light.
Implementation Method 2
a reflective diffusion plate
Implementation Method 3
diffused light, which is reflected light emitted from the reflective diffusion plate
Data Source
AI summary
A light source device includes a laser source unit, a rotating body including a phosphor layer and a reflective diffusion plate, and an optical path forming member that divides the emitted light of the laser source unit into a first laser beam and a second laser beam, irradiates the reflective diffusion plate with the first laser beam, and irradiates the phosphor layer with the second laser beam. The optical path forming member includes a first reflection plate with a through-hole and a first collimator lens. The first laser beam passes through the through-hole and the first collimator lens in that order and enters the reflective diffusion plate, and the diffused light from the reflective diffusion plate passes through the first collimator lens and enters the first reflection plate.