Method for measuring brightness uniformity of a panel
View Patent ↗A method for measuring brightness uniformity of a panel is disclosed. The method includes steps of: dividing the panel into a plurality of areas, measuring brightness of each area, calculating each area of an average value K the brightness differences between the area and the other adjacent areas, and comparing the value K with a predetermined value. When the value K is greater than the predetermined value, it indicates that the brightness difference between the area and the adjacent areas exceeds a uniformity threshold. When the value K is smaller than the predetermined value, it indicates that the brightness difference between the area and the adjacent areas is below the uniformity threshold. The entire panel is evaluated to ensure accuracy of measuring results.
1. A method for measuring brightness uniformity of a panel, the method comprising the steps of:
dividing the panel into a plurality of areas;
measuring brightness of each area;
calculating a value K for each area, where the value K is represented by:
K
=
∑
n
[
L
k
-
L
n
/
L
n
]
+
∑
m
[
L
k
-
L
m
/
2
L
m
]
m
+
n
,
where L k is brightness of the area, L n is brightness of adjacent areas which are perpendicular or parallel to the area, L m is brightness of the adjacent areas which are diagonal with the area, n is the number of the adjacent areas which are perpendicular or parallel to the area, and m is the number of the adjacent areas which are diagonal with the area; and
comparing the value K with a predetermined value, wherein when the value K is greater than the predetermined value, it indicates that the brightness difference between the area and the adjacent areas exceeds a uniformity threshold, and when the value K is smaller than the predetermined value, it indicates that the brightness difference between the area and the adjacent areas is below the uniformity threshold.
2. The method of claim 1 , wherein the panel is a liquid crystal display (LCD) panel.
3. The method of claim 1 , wherein the panel is an LCD backlight panel.
4. The method of claim 1 , wherein the panel is equally divided into a plurality of areas.
5. The method of claim 4 , wherein the areas are arranged in a matrix.
6. The method of claim 5 , wherein the measuring step is to measure brightness of all the areas at the same time.
7. The method of claim 5 , further comprising dividing the areas into a plurality of blocks so that each block comprises plural areas.
8. The method of claim 7 , wherein the measuring step is to measure brightness of all areas of at least one block at the same time.
9. The method of claim 5 , wherein the measuring step is to measure brightness of the areas one by one.
10. The method of claim 9 , wherein each area is a circular area.
11. The method of claim 10 , wherein the step of measuring the brightness of the areas one by one comprises disposing a measuring instrument at a distance Z from the panel, so that the measuring instrument receives lights from the panel at a vision angle θ, that a radius r of each measured area is r=z tan(θ/2) and that the number of the measured areas is (L/2r)*(W/2r), where L is the length of the panel and W is the width of the panel.
12. The method of claim 11 , wherein the distance Z is about 50 cm and the angle θ is about 1 degree.
13. The method of claim 1 , wherein the predetermined value ranges from 0.013 to 0.017.
14. The method of claim 1 , further comprising making a chart according to the value K calculated for each area.
15. The method of claim 14 , further comprising marking in the chart areas with the value K which exceeds the predetermined value.
16. The method of claim 1 , wherein the measuring step comprises utilizing a charge-coupled device (CCD) to measure the panel.