Lens Mirror Array Stray Light Reduction via Extraction
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Solution Overview
Problem
Conventional lens arrays in image forming apparatuses suffer from deteriorated imaging properties and light intensity variations due to optical axis deviations, which are exacerbated by the combination of lenses and apertures, leading to increased stray light and reduced optical efficiency.
Innovation Solution
A lens mirror array is designed with a first convex lens surface, a first mirror surface, a second mirror surface, and a second convex lens surface, where the second mirror surface is shaped to protrude towards the first mirror surface, and a light-shielding member is positioned to prevent stray light from entering adjacent optical elements, thereby reducing stray light and improving optical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the groove depth L of mirror surface is made larger than the mirror width WO to reduce stray light, then stray light is reduced, but the flow of resin during molding deteriorates and molding time becomes long
Solution Approach 1:
The patent extracts the light-shielding function from the mirror groove structure and implements it through a separate light-shielding member positioned in the space between adjacent optical elements. This allows the mirror groove depth to be optimized for optical performance while the light-shielding member handles stray light prevention, avoiding the need for excessively deep grooves that would prolong molding time.
Solution Approach 2:
The patent introduces a light-shielding member as an intermediary element between adjacent optical elements. This mediator blocks stray light from entering neighboring elements without requiring the mirror groove depth to be increased, thus resolving the conflict between stray light reduction and molding efficiency.
2Object-generated harmful factors
If the groove depth L of mirror surface is made larger than the mirror width WO to reduce stray light, then stray light is reduced, but the width of protrusion to pitch becomes narrow reducing optical efficiency
Solution Approach 1:
The patent separates the stray light blocking function from the mirror groove structure by introducing a dedicated light-shielding member. This allows the protrusion width to be optimized for optical efficiency while the light-shielding member handles stray light prevention independently.
3Ease of operation
If lenses and apertures are combined together to form a lens array, then imaging function is achieved, but property of the lens array is deteriorated due to deviation at the time of assembly
Solution Approach 1:
The patent merges the lens and mirror into a single integral optical element, eliminating the need for separate assembly of multiple components. This integration ensures that the optical axis of the lens and the reflection surface of the mirror are precisely aligned by definition, as they are formed as one piece through molding, thereby avoiding alignment deviations.
Solution Approach 2:
The patent creates a multi-functional optical element that combines both lens and mirror functions in a single component. This universal element performs both refraction and reflection while maintaining precise optical axis alignment, eliminating the need for separate aperture components and reducing assembly complexity.
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 solution effectively minimizes stray light and enhances optical efficiency by separating regular and stray light paths, maintaining high imaging quality and reducing the risk of mechanical strength issues and prolonged molding times associated with previous designs.
Implementation Method 1
a first lens surface configured to be formed at the top of convex portion protruding outwards and converge light
Implementation Method 2
a first mirror surface configured to reflect the light emitted from the first lens surface
Implementation Method 3
a second mirror surface configured to reflect the light reflected by the first mirror surface
Implementation Method 4
a second lens surface configured to image the light emitted from the second mirror surface on an image plane
Data Source
AI summary
An example is a lens mirror array in which many optical elements, each of which comprises a first lens surface that is formed at the top of convex portion protruding outwards and converges light, a protrusion that includes a first mirror surface which reflects the light emitted from the first lens surface at the top and a light-shielding surface that has side walls at two sides thereof with respect to a light advancing direction and prevents advance of the light through the side walls, a second mirror surface that reflects the light reflected by the first mirror surface of the protrusion and a second lens surface that images the light emitted from the second mirror surface on an image plane, is arranged in a horizontal scanning direction; by comparing both ends in the horizontal scanning direction with the center in the horizontal scanning direction.