Image display medium ribs, production process thereof, and image display medium using the ribs

DETAILED DESCRIPTION A theme of the present invention is to solve the problems with the conventional art and achieve the following object.
Specifically, an object of the present invention is to provide ribs for an image display medium, which enable provision of a high-image quality image display medium with a cell-form arrangement, a narrow rib width and a high open area ratio, and a process for fabricating the ribs and a high-image quality image display medium which utilizes the ribs.
The problem described above is solved by the following: A first aspect of the present invention is to provide ribs for an image display medium, which are retainable between a pair of substrates, which ribs have been formed by liquid injection molding (LIM molding) including the use of heat-curable epoxy resin and have been formed such that the ribs form a cell-form arrangement.
A base width of the ribs may be at least 5 .
mu.
m and at most 200 .
mu.
m and a ratio of a half-height width of the ribs to the base width of the ribs may be at least 0.
1 and at most 0.
7.
A height of the ribs may be at least 50 .
mu.
m and at most 1000 .
mu.
m, and a spacing of the ribs may be at least 20 .
mu.
m and at most 5000 .
mu.
m.
In case the ribs are formed with a sheet, a thickness of a base plate portion of the sheet may be at least 3 .
mu.
m and at most 200 .
mu.
m.
A viscosity at 25.
degree.
C.
of the heat-curable epoxy resin before curing may have been at least 0.
1 Pas and at most 100 Pas.
A Shore D hardness at 25.
degree.
C.
of the heat-curable epoxy resin after curing may be at least 1 and at most 100.
Coloration may be black or colorless transparency with an overall light transmissivity of at least 70%.
Conditions of the liquid injection molding process (LIM molding) may feature an injection temperature of at most 40.
degree.
C.
and a mold temperature of at most 150.
degree.
C.
The ribs may be formed so as to form a lattice pattern.
A second aspect of the present invention is to provide an image display medium including: a pair of substrates; and ribs retained between the pair of substrates, which ribs have been formed by liquid injection molding (LIM molding) including the use of heat-curable epoxy resin and have been formed such that the ribs form a cell-form arrangement