Projector Light Shielding Plate Thermal Deterioration Prevention

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Solution Overview

Problem

In projectors, the light shielding plate used for image mute tends to thermally deteriorate due to increased luminance of the light source device, as it absorbs most of the luminous flux, leading to potential damage to both the light shielding plate and other optical elements.

Innovation Solution

A projector design that includes a light control device upstream of the shutter device, which reduces the luminous flux incident on the light shielding plate by shielding a portion of it, thereby minimizing the temperature rise and preventing thermal deterioration, while also preventing unnecessary light from reaching downstream optical elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a light shielding plate is provided in one place inside the optical path to set image mute, then the image mute function is achieved, but the light shielding plate absorbs most of the luminous flux and is likely to be raised to a high temperature, causing thermal deterioration

Engineering Contradiction:

Improveimage mute functionVSAvoidtemperature of light shielding plate

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent divides the light shielding function into two separate components: a light control device with light shielding blades positioned upstream, and a shutter device with a light shielding plate positioned downstream. This segmentation distributes the thermal load, preventing the downstream light shielding plate from absorbing the entire luminous flux and overheating, while still achieving the image mute function when both components work together.

Inventive Principle:

Principle #1Segmentation

2Illumination intensity

If the luminance of the light source device is increased, then the projection brightness is improved, but the light shielding plate is more likely to thermally deteriorate due to increased luminous flux absorption

Engineering Contradiction:

Improveprojection brightnessVSAvoidthermal stability of light shielding plate

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

By segmenting the light shielding function between upstream light control device and downstream shutter device, the patent enables the system to handle higher luminance from the light source without overloading a single light shielding plate, thus maintaining both projection brightness and thermal stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The upstream light control device acts as an intermediary that pre-shields a portion of the luminous flux before it reaches the downstream light shielding plate. This intermediate shielding reduces the thermal load on the main light shielding plate, allowing the system to maintain higher projection brightness without compromising the thermal stability of the light shielding plate.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the light shielding plate is moved into the optical path to shield luminous flux, then image mute is achieved, but unnecessary luminous flux is made incident on downstream optical elements, potentially causing their thermal deterioration

Engineering Contradiction:

Improveimage mute functionVSAvoidthermal exposure of downstream optical elements

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The upstream light control device performs preliminary shielding of the luminous flux before it reaches the downstream optical elements. When image mute is activated, the light control device's blades are positioned to block light in advance, preventing unnecessary luminous flux from reaching downstream optical elements like the liquid crystal panel, thus protecting them from thermal deterioration.

Inventive Principle:

Principle #10Preliminary action

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 design effectively suppresses the thermal deterioration of the light shielding plate and optical elements, increasing the projector's lifespan and maintaining a balanced temperature control.

Implementation Method 1

the light control device... changes the area of a light passage through which the luminous flux passes, controlling the quantity of the luminous flux

Methodology Applied

Scientific EffectLight shielding: Absorption (EM radiation)

Implementation Method 2

the light shielding plate... shields the luminous flux by the light shielding plate moving into the optical path... the light shielding plate is likely to be raised to a high temperature

Methodology Applied

Scientific EffectLight absorption and heating: Absorption (EM radiation)

Data Source

PatentUS9028075B2Projector for preventing thermal deterioration of a light shielding member

Publication Date: 2015.05.12 SEIKO EPSON CORP

AI summary

A projector includes: a light source device; an optical modulation device configured to modulate a luminous flux emitted from the light source device in accordance with image information, forming an image; a projection optical device configured to project the image; a shutter device including a light shielding plate which can move into and out of an optical path of the luminous flux ranging from the light source device to the optical modulation device, shields the luminous flux by the light shielding plate moving into the optical path; and a light control device which being disposed on the optical path's upstream side of the shutter device, changes the area of a light passage through which the luminous flux passes, controlling the quantity of the luminous flux.