Projector Aspherical Optical Element Illuminance Uniformity
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Solution Overview
Problem
Existing projector technologies face color unevenness issues due to differences in illuminance distribution between blue light and other colors, caused by the independent optical paths for illumination and excitation light, leading to imbalanced white balance and image quality.
Innovation Solution
The projector employs a first light source device emitting yellow fluorescent light and a second light source device emitting blue light, with an aspherical concave mirror and compensating plate to increase field curvature and barrel distortion, ensuring uniform illuminance distribution across the image forming region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If independent optical paths are provided for illumination light and excitation light, then white balance control is improved, but illuminance distribution uniformity deteriorates
Solution Approach 1:
The patent introduces an aspherical optical element with specific curvature parameters to modify the illuminance distribution of blue light. By changing the optical parameters (aspherical coefficients) of the optical element, the patent adjusts the light distribution to match between different color channels while maintaining the independent optical path structure for white balance control.
Solution Approach 2:
The patent adds an aspherical optical element as an intermediary component in the blue light optical path. This optical element acts as a mediator to adjust and equalize the illuminance distribution without affecting the independent optical path structure, thereby resolving the contradiction between white balance control and illuminance uniformity.
2Ease of operation
If a dichroic mirror with polarized light separating function is used, then light path control is improved, but white balance stability deteriorates
Solution Approach 1:
The patent extracts the polarized light separating function from the dichroic mirror by providing separate optical paths for illumination light and excitation light. This separation removes the source of white balance instability (thermal stress affecting polarized light separation) while maintaining effective light path control through dedicated optical components for each function.
3Illumination intensity
If blue light illuminance is increased to match other colors, then color unevenness is reduced, but optical path complexity increases
Solution Approach 1:
The aspherical optical element serves multiple functions: it adjusts illuminance distribution, corrects optical aberrations, and maintains beam quality simultaneously. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in optical path complexity while achieving uniform illuminance distribution.
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 achieves uniform illuminance distribution for blue and other colors, reducing color unevenness and improving image quality by matching the illuminance profiles of different light modulators.
Implementation Method 1
a first light source device configured to emit first light having a first wavelength band... The first light source device includes a first light emitting element configured to emit excitation light having an excitation wavelength band and a wavelength converter configured to convert the excitation light into the first light having the first wavelength band different from the excitation wavelength band
Implementation Method 2
a second light source device configured to emit second light having a second wavelength band different from the first wavelength band... The second light source device includes a second light emitting element configured to emit the second light, and a diffuser configured to diffuse the second light emitted from the second light emitting element
Implementation Method 3
an optical element having an aspherical surface. The optical element is disposed on an optical path of the second light between the diffuser and the second light modulator and is configured to increase field curvature on the second light modulator
Data Source
AI summary
A projector includes a first light source device configured to emit first light having a first wavelength band, a second light source device configured to emit second light having a second wavelength band, a first light modulator configured to modulate the first light, and a second light modulator configured to modulate the second light. The first light source device includes a first light emitting element configured to emit excitation light and a wavelength converter configured to convert the excitation light into the first light. The second light source device includes a second light emitting element configured to emit the second light, a diffuser configured to diffuse the second light, and an optical element having an aspherical surface. The optical element is disposed on an optical path of the second light between the diffuser and the second light modulator and is configured to increase field curvature on the second light modulator.