Light-Transmitting Ceramic Sintered Body with Controlled Porosity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light-transmitting ceramic sintered bodies produced by pressure-sintering methods are expensive and have high reflectance, while those produced by normal-pressure sintering methods have low visibility due to air bubbles, which affect transmittance and reflectance in contradictory ways, making it challenging to achieve transparency and good visibility at a low cost.
Innovation Solution
A light-transmitting ceramic sintered body with air bubbles of specific size and quantity, produced by a normal-pressure sintering method, achieving high transmittance and clarity while maintaining low reflectance, using a composition that includes Al2O3, AlN, and sintering additives, and a production method involving primary and secondary sintering steps to control porosity and crystal grain size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pressure-sintering method (hot-press or HIP process) is applied to reduce air bubbles, then transmittance is improved, but production cost increases and reflectance increases
Solution Approach 1:
The invention changes the sintering parameters by using normal-pressure sintering instead of pressure-sintering, and by controlling air bubble size (1-5 μm) and concentration (10-4000 bubbles/mm³), achieving both low cost and high transmittance without requiring expensive pressure-sintering processes
Solution Approach 2:
The invention accepts and optimizes the presence of controlled air bubbles (porosity) rather than eliminating them completely. By controlling air bubble size and distribution, the material achieves sufficient light transmission while avoiding the need for expensive pressure-sintering to remove all bubbles
2Illumination intensity
If pressure-sintering method is applied to reduce air bubbles, then transmittance is improved, but reflectance increases
Solution Approach 1:
The invention changes the approach by not removing air bubbles but rather controlling their characteristics (size: 1-5 μm, concentration: 10-4000 bubbles/mm³). This parameter control allows the material to maintain low reflectance while achieving high transmittance, as the controlled air bubbles do not create significant surface reflections
3Ease of manufacture
If normal-pressure sintering method is used to reduce cost, then production cost decreases, but visibility deteriorates due to air bubbles
Solution Approach 1:
The invention optimizes air bubble parameters (size: 1-5 μm, concentration: 10-4000 bubbles/mm³) to ensure that even with normal-pressure sintering, the material achieves sufficient visibility. The controlled air bubble characteristics prevent excessive light scattering while maintaining the cost advantage of normal-pressure processing
Solution Approach 2:
The invention embraces controlled porosity from normal-pressure sintering by optimizing air bubble size and distribution. This allows the material to maintain good visibility despite the presence of air bubbles, avoiding the need for expensive pressure-sintering while achieving acceptable optical performance
4Object-generated harmful factors
If air bubbles are present to maintain low reflectance, then reflectance decreases, but transmittance and visibility deteriorate
Solution Approach 1:
The invention optimizes air bubble parameters (size: 1-5 μm, concentration: 10-4000 bubbles/mm³) to find the optimal balance point where reflectance is minimized while transmittance is maximized. This parameter optimization resolves the contradiction by controlling the physical characteristics of air bubbles to achieve both low reflectance and high transmittance simultaneously
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 enables the production of a transparent ceramic sintered body with high transmittance and clarity at a lower cost, effectively addressing the cost and visibility issues of conventional methods by optimizing air bubble distribution and composition.
Implementation Method 1
a light-transmitting ceramic sintered body containing air bubbles each having a pore size of 1 μm or more and less than 5 μm
Implementation Method 2
the transmittance, visibility (legibility), reflectance, etc. of the light-transmitting ceramic body are considered to be affected by air bubbles in the sintered body
Data Source
AI summary
The present invention relates to a light-transmitting ceramic sintered body which contains air voids having pore diameters of 1 μm or more but less than 5 μm at a density within the range of from 10 voids/mm3 to 4,000 voids/mm3 (inclusive), while having a closed porosity of from 0.01% by volume to 1.05% by volume (inclusive). With respect to this light-transmitting ceramic sintered body, a test piece having a thickness of 1.90 mm has an average transmittance of 70% or more in the visible spectrum wavelength range of 500-900 nm, and the test piece having a thickness of 1.90 mm has a sharpness of 60% or more at a comb width of 0.5 mm.