Image Projection Apparatus Diaphragm Light Source Synchronization

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Solution Overview

Problem

Existing image projection technologies face image quality degradation due to uncorrected color changes when diaphragm control and light source adjustments are made simultaneously, leading to incomplete correction of color unbalance and spectral changes.

Innovation Solution

An image projection apparatus that synchronizes the control of a diaphragm and a light source through a CPU-managed system, using a light amount gain calculator, allocator, shutter controller, and light source controller to adjust light amounts and apply color corrections based on APL values and user-set brightness, with tables for color correction to maintain image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the light amount of the light source is changed to improve contrast, then the contrast of the projection image is improved, but spectral change occurs causing color unbalance

Engineering Contradiction:
ImprovecontrastVSAvoidcolor accuracy
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the light amount of the light source based on the APL value of the input image signal. When the APL value indicates a dark image, the light amount is increased to improve contrast; when the APL value indicates a bright image, the light amount is decreased. This dynamic parameter adjustment resolves the contradiction by adapting the illumination intensity to the image content while maintaining color accuracy through coordinated diaphragm control and color correction.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If the diaphragm is controlled to adjust light amount, then the contrast is improved, but color unbalance occurs due to spectral changes

Engineering Contradiction:
ImprovecontrastVSAvoidcolor balance
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent merges the control of the diaphragm and the light source into a coordinated system. Both components are controlled simultaneously based on the APL value, with the diaphragm controlling the light amount entering the optical modulator and the light source controlling the overall light output. This combined control approach allows the system to maintain color balance while improving contrast, as both elements work together to adjust the light path and intensity without causing spectral imbalance.

Inventive Principle:
Principle #5Merging (Combining)

3Illumination intensity

If both diaphragm control and light source control are applied simultaneously, then contrast improvement is achieved, but color correction becomes incomplete

Engineering Contradiction:
ImprovecontrastVSAvoidcolor correction completeness
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by implementing different control strategies for different parts of the optical system. The diaphragm controls the spatial distribution of light entering the optical modulator, while the light source controls the overall light intensity. Additionally, color correction is applied specifically to compensate for spectral changes caused by light amount adjustments. This localized control approach ensures that each component performs its specific function optimally, achieving both contrast improvement and complete color correction.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3506630B1Image projection apparatus, its control method, and control program
Publication Date: 2023.07.19 CANON KK
  • EP3506630B1 patent drawingFigure 1
  • EP3506630B1 patent drawingFigure 2~3B
  • EP3506630B1 patent drawingFigure 4

AI summary

An image projection apparatus (100) includes an optical element (115) configured to change an amount of light emitted from a light source (116), an information acquirer (103) configured to acquire information on a gradation of the image signal, a corrector (105) configured to correct the image signal in accordance with a change in the light amount, and a controller (101, 108, 109, 110) configured to correct the image signal based on at least one of first correction data used to correct the image signal in accordance with the change in the light amount caused by controlling (110) the optical element, and second correction data used to correct the image signal in accordance with the change in the light amount caused by controlling (111) the supply power.