Composite sheet and display substrate using same

1. A composite sheet comprising:

a binder comprising an oxetane-epoxy compound represented by Formula 1

wherein R 1 is hydrogen, a methyl group, or an ethyl group; and

a glass filler, wherein a difference in refractive index between the binder and the glass filler is about 0.01 or less.

2. A composite sheet comprising:

100 parts by weight of a binder comprising an oxetane-epoxy compound represented by Formula 1:

wherein R 1 is hydrogen, a methyl group, or an ethyl group; and

about 60 parts by weight to about 300 parts by weight of a glass filler.

3. The composite sheet according to claim 1 , wherein the glass filler comprises at least one selected from the group consisting of glass fibers, glass fiber cloths, glass fabrics, non-woven glass fabrics, glass meshes, glass beads, glass powders, and glass flakes.

4. The composite sheet according to claim 1 , wherein the binder further comprises a cationic polymerizable compound.

5. The composite sheet according to claim 4 , wherein the cationic polymerizable compound comprises at least one selected from the group consisting of epoxy group-containing compounds, oxetane group-containing compounds, vinyl ether group-containing compounds, and caprolactam group-containing compounds.

6. The composite sheet according to claim 1 , further comprising: a cationic initiator.

7. The composite sheet according to claim 1 , wherein the composite sheet has a glass transition temperature of about 200° C. or more.

8. The composite sheet according to claim 1 , wherein the composite sheet has a glass transition temperature of about 250° C. or more.

9. A display substrate comprising the composite sheet according to claim 1 .

10. The display substrate according to claim 9 , wherein the display substrate has a coefficient of thermal expansion of about 30 ppm/° C. or less, as measured using a TMA at 5° C./min from 30° C. to 250° C.