Illuminating Device Upstream Infrared Source Narrow Beam

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Solution Overview

Problem

The utilization efficiency of light from second light sources, such as infrared-light point sources, is deteriorated due to blockage by first light sources, like white-point light sources, in existing illuminating devices, particularly when the array pitch of the first light sources is narrower and their directivity angle is wider, leading to reduced radiation intensity on the edge side.

Innovation Solution

The illuminating device arranges infrared-light point sources with a smaller half-value angle on an upstream side of white-point light sources, ensuring that the directivity angle of the second light sources is narrower than that of the first light sources, preventing blockage and maintaining efficient light utilization by optimizing the positions and directivity of both types of light sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the array pitch of the first light sources is narrowed to increase light output, then the light utilization efficiency improves, but the blockage of second light sources by first light sources increases, causing radiation intensity to deteriorate on the edge side

Engineering Contradiction:
Improvelight outputVSAvoidradiation intensity on edge side
Core Design Contradiction:
ProductivityVSIllumination intensity

Solution Approach 1:

The patent applies local quality by differentiating the directivity characteristics of different light sources based on their position. First light sources (white-point LEDs) have a wider half-value angle for broader illumination coverage, while second light sources (infrared LEDs) have a narrower half-value angle to prevent blockage. This localized optimization of directivity angles resolves the contradiction between maximizing light output and maintaining edge-side radiation intensity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of directivity angle (half-value angle) to resolve the contradiction. By setting the half-value angle of second light sources to be smaller than that of first light sources, the system enables narrower light beams from upstream sources to pass through gaps between downstream sources without blockage, thereby maintaining radiation intensity even when array pitch is narrowed.

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If the directivity angle of the second light sources is widened to improve illumination coverage, then the illumination area increases, but the blockage by first light sources increases, causing light utilization efficiency to deteriorate

Engineering Contradiction:
Improveillumination areaVSAvoidlight utilization efficiency
Core Design Contradiction:
Area of stationary objectVSLoss of energy

Solution Approach 1:

The patent applies local quality by assigning different directivity characteristics to different light sources. Second light sources (infrared) use a narrower half-value angle to penetrate through the array structure without blockage, while first light sources (white-point) use a wider half-value angle for comprehensive illumination. This differentiated approach allows each light source to optimize its function without compromising the other.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent resolves the contradiction by considering the spatial arrangement in multiple dimensions. By positioning second light sources upstream and giving them narrower directivity, the system creates a three-dimensional light path configuration where narrower beams can pass through gaps between first light sources without blockage, effectively utilizing the spatial dimension to overcome the apparent trade-off between coverage and efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Volume of moving object

If the array pitch of light sources is narrowed to reduce device size, then the compactness improves, but the blockage of light paths increases, causing radiation intensity to deteriorate

Engineering Contradiction:
Improvedevice sizeVSAvoidradiation intensity
Core Design Contradiction:
Volume of moving objectVSIllumination intensity

Solution Approach 1:

The patent changes the directivity parameter (half-value angle) of light sources to enable compact arrangement. By setting the half-value angle of second light sources to be smaller than that of first light sources, the system allows narrower light beams to pass through the reduced spacing without significant blockage, thereby achieving both compactness and maintained radiation intensity.

Inventive Principle:
Principle #35Parameter changes

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 effectively prevents the deterioration of light utilization efficiency, ensuring consistent and optimal radiation intensity across the scanning area, thereby improving the quality of the image scanned and read.

Implementation Method 1

a plurality of infrared-light point sources 701 arranged on an upstream side of the multiple white-point light sources 501 in an irradiation direction of light

Methodology Applied
Scientific EffectLight emission from LED: Light Emitting Diode

Data Source

PatentEP4128734B1Illuminating device, image reading device, and image forming apparatus
Publication Date: 2024.10.23 RICOH CO LTD
  • EP4128734B1 patent drawingFigure 1~2
  • EP4128734B1 patent drawingFigure 3~4
  • EP4128734B1 patent drawingFigure 5~6

AI summary

An illuminating device (401), an image reading device (130), and an image forming apparatus (1). The illuminating device (401) includes a plurality of first light sources (501) arrayed on a circuit board (502), the first light sources (501) having a plurality of first light emitting surfaces (S1) through which light is emitted, and a second light source (701) disposed on an upstream side of the first light sources (501) in an irradiation direction of the light. In the illuminating device (401), the second light source has a second light emitting surface through which light is emitted, and the second light source has a directivity angle different from a directivity angle of each one of the first light sources. The image reading device (130) includes the illuminating device (401), and an imaging device (405) to receive the light reflected by a document to capture an image of the document.