Light Scanning Optics With Diffractive Power Ratio for Astigmatism
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Solution Overview
Problem
Conventional light scanning apparatuses fail to sufficiently suppress astigmatism due to temperature changes, despite configurations aimed at reducing optical performance deterioration.
Innovation Solution
The apparatus employs a single diffracting optical element for each incident optical system, with a defined ratio between refractive and diffractive powers to stabilize optical performance across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a diffracting surface is added to the incident optical system to suppress temperature-induced optical performance deterioration, then thermal stability is improved, but astigmatism increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the ratio between refractive power and diffractive power within the range 1.00 ≤ |Pdm/Prm| ≤ 1.50. This parameter optimization allows the incident optical system to simultaneously achieve thermal stability compensation and astigmatism suppression, resolving the technical contradiction between temperature compensation and image quality
Solution Approach 2:
The incident optical system uses a composite optical element that integrates both refracting and diffracting surfaces. This composite structure enables the system to exploit both refraction and diffraction effects, allowing simultaneous compensation for thermal expansion and control of astigmatism through the balanced power ratio
2Temperature
If the ratio between diffractive power and refractive power is increased to improve temperature compensation, then thermal stability is improved, but astigmatism increases
Solution Approach 1:
The patent establishes an optimal parameter range for the power ratio (1.00 ≤ |Pdm/Prm| ≤ 1.50) that balances temperature compensation effectiveness with optical performance stability. This parameter optimization ensures that the system maintains reliable optical performance while achieving sufficient temperature compensation
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 suppresses astigmatism and maintains optical performance stability even with temperature fluctuations, ensuring precise scanning and image quality.
Implementation Method 1
a first incident optical system which includes a first optical portion having a diffracting surface, and is configured to guide the first light flux from the first light source to a first deflecting surface of the deflecting unit
Data Source
AI summary
A light scanning apparatus according to the present embodiments includes a deflecting unit configured to deflect a first light flux from a first light source to scan a first scanned surface in a main scanning direction, and a first incident optical system which includes a first optical portion having a diffracting surface, and is configured to guide the first light flux from the first light source to a first deflecting surface of the deflecting unit, in which a condition of 1.00<|Pdm|/|Prm|≤1.50 is satisfied, where Prm and Pdm represent a refractive power and a diffractive power in a main scanning cross section of the first optical portion, respectively.