Projector Light Timing for Liquid Crystal Illuminance Uniformity
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Solution Overview
Problem
Existing projectors face issues with illuminance unevenness in projected images due to variations in light intensity during the rising and falling periods of liquid crystal modulation, leading to potential illuminance fluctuations and unevenness on the projection surface.
Innovation Solution
A projector design that includes a light source device emitting first light, a light scanning device for cyclic scanning, a light modulation device with a liquid crystal element, and a projection optical system, synchronized to modulate light in specific periods to maintain consistent illuminance and reduce unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light source device continuously emits illumination light to the liquid crystal display element, then the image display function is maintained, but illuminance unevenness occurs during the rising and falling periods of liquid crystal modulation
Solution Approach 1:
The illumination light is emitted periodically in synchronization with the liquid crystal modulation cycle, specifically illuminating during the period when the liquid crystal has completed its response (after rising and falling periods). This periodic illumination timing ensures that illuminance is applied only when the liquid crystal state is stable, preventing illuminance unevenness while maintaining continuous image display functionality.
2Speed
If the illumination light is scanned during the liquid crystal response period, then the scanning function is achieved, but illuminance fluctuations occur on the projection surface
Solution Approach 1:
The light scanning operation is performed periodically in synchronization with the liquid crystal modulation cycle, specifically scanning and illuminating the liquid crystal display element only during the period after the liquid crystal has completed its response. This timing coordination ensures that scanning occurs when the liquid crystal state is stable, maintaining illuminance stability while achieving the scanning function.
3Productivity
If the light source emits light during the rising and falling periods of liquid crystal, then the image formation cycle is continuous, but color tone reproduction becomes inaccurate
Solution Approach 1:
The light source emits illumination light periodically in synchronization with the liquid crystal modulation cycle, specifically illuminating only during the period after the liquid crystal has completed its rising and falling responses. This timing ensures that illumination occurs when the liquid crystal state is stable and accurately reflects the input image information, thereby achieving accurate color tone reproduction while maintaining continuous image formation through coordinated cycling of light emission and liquid crystal modulation.
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
The synchronized scanning and modulation system ensures consistent illuminance and reduces illuminance unevenness, improving image quality by ensuring each pixel receives light only after its response is complete, thus accurately reproducing color tones and enhancing image clarity.
Implementation Method 1
a modulation period TAL in which the three color lights (first light) contained in the white light WL are modulated in the liquid crystal layer (62) includes a first period T1 from a time when the electrical signal is input to a time when an amount of modulation reaches a predetermined value and a second period T2 in which a refractive index is held at a predetermined value
Data Source
AI summary
A projector according to the present disclosure includes a light source device that cyclically emits a first light, a light scanning device that cyclically scans the first light, a light modulation device that modulates the first light emitted from the light scanning device, and a projection optical system that projects an image light emitted from the light modulation device. The light modulation device includes a liquid crystal element that converts the first light into the image light. A modulation period in which the first light is modulated in a liquid crystal layer of the liquid crystal element includes a first period from a time when an electrical signal is input to a time when an amount of modulation changes to a predetermined value, and a second period in which a refractive index is held. The first light is incident on the light modulation device in the second period.