Glass plate suitable for image display device
The present disclosure provides a glass plate including a main surface having a plurality of minute deformed portions which are recesses or projections, wherein, where an average value of lengths of two sides adjacent to each other of a minimum quadrilateral with four right angles surrounding each minute deformed portion is defined as a dimension, an average value of the dimensions of the plurality of deformed portions is 3.2 to 35.5 μm. The glass plate satisfies a condition a1 that a ratio of deformed portions A1 having the dimensions of 0.5 to 3.0 μm with respect to the plurality of deformed portions in terms of number is less than 5%, and/or a condition d1 that a coefficient of variation of the dimensions is 40% or less. This glass plate is suitable for suppressing sparkle and is highly practical, when disposed on an image display device.
1. A glass plate comprising a main surface having a plurality of minute deformed portions, wherein
the plurality of minute deformed portions are a plurality of recesses or a plurality of projections,
where an average value of lengths of two sides adjacent to each other of a minimum quadrilateral with four right angles surrounding each minute deformed portion as observed from a direction perpendicular to the main surface is defined as a dimension of the minute deformed portion, and an average value of the dimensions of the plurality of minute deformed portions is 3.2 μm to 35.5 μm,
at least one of the following conditions is satisfied:
a condition a1 that a ratio of minute deformed portions A1 having the dimensions of 0.5 μm to 3.0 μm with respect to the plurality of minute deformed portions in terms of number is less than 5%; and
a condition d1 that a coefficient of variation of the dimensions of the plurality of minute deformed portions is 40% or less, and
3 to 30 bright spots are observed on a 2-dimensional Fourier transform image of a processed image having been subjected to binarization processing A for discriminating the plurality of minute deformed portions from their surrounding region in a 200 μm square region on the main surface observed from the above direction, or one bright spot is observed on the 2-dimensional Fourier transform image of the processed image having been subjected to the binarization processing A and two or more bright spots are observed on a 2-dimensional Fourier transform image of a processed image having been subjected to binarization processing B instead of the binarization processing A,
where the binarization processing A is binarization processing performed with an image divided into pixels of 256×256, and the binarization processing B is binarization processing performed with an image divided into pixels of 65536×65536.
2. The glass plate according to claim 1 , wherein
the plurality of minute deformed portions are a plurality of recesses.
3. The glass plate according to claim 1 , wherein
the plurality of minute deformed portions are a plurality of projections.
4. The glass plate according to claim 1 , wherein
where gloss is denoted by X (%) and haze is denoted by Y (%), and at least one of relational expressions Y≤−⅙X+20 and Y≤− 1/40X+8 is satisfied.
5. The glass plate according to claim 4 , wherein Y≤− 1/40X+8 is satisfied.
6. The glass plate according to claim 1 , wherein
a condition b that a ratio of minute deformed portions B having the dimensions greater than 35.5 μm with respect to the plurality of minute deformed portions in terms of number is less than 15%, is satisfied.
7. The glass plate according to claim 1 , wherein
the coefficient of variation of the dimensions of the plurality of minute deformed portions is 23% or less.
8. The glass plate according to claim 1 , wherein
as observed from the direction, the plurality of minute deformed portions include
a first minute deformed portion corresponding to i) a minute deformed portion having a straight section contacting a receding portion of the quadrilateral, wherein the receding portion recedes from a part that is selected from sides of the quadrilateral and does not include a vertex of the quadrilateral, or ii) a minute deformed portion which is a polygon of which at least one internal angle is a reflex angle, and
a second minute deformed portion having a shape different from the first minute deformed portion.
9. The glass plate according to claim 8 , wherein
the shape of the second minute deformed portion corresponds to neither the i) nor the ii).
10. The glass plate according to claim 1 , wherein
the average value of the dimensions of the plurality of minute deformed portions is 3.2 μm or greater and 13.6 μm or smaller.
11. The glass plate according to claim 1 , wherein
the average value of the dimensions of the plurality of minute deformed portions is 7 μm or greater and 13.6 μm or smaller.