Fixing apparatus for reducing noise of backlit unit

1. A fixing apparatus, applied to a diffuser plate of a backlight unit (BLU), the fixing apparatus comprising:

a receiving portion, symmetrically formed at a first centrosymmetric line of a diffuser plate, and a first pair of edges of the receiving portion setting at two sides of the first centrosymmetric line; and

a positioning portion located within the receiving portion such that a first distance is formed between the positioning portion and the first pair of edges of the receiving portion, the first distance determined by a mechanical tolerance of the diffuser plate,

wherein movement of the diffuser plate along a direction of a second centrosymmetric line perpendicular to the first centrosymmetric line, is constrained by the positioning portion.

2. The fixing apparatus according to claim 1 , wherein the receiving portion further comprises a second pair of edges intersecting the first pair of edges, a second distance formed between the positioning portion and the second pair of edges, the second distance determined according to an overall expansion coefficient of the diffuser plate.

3. A fixing apparatus, applied to a diffuser plate of a backlight unit (BLU), the fixing apparatus comprising:

a fixing hole, symmetrically formed at a centrosymmetric line of a diffuser plate, a first pair of edges setting at two sides of the centrosymmetric line, and a second pair of edges cutting across the centrosymmetric line; and

a positioning pin, located within the fixing hole, and separated from the first pair of edges of the fixing hole at a first distance, and separated from the second pair of edges of the fixing hole at a second distance,

wherein the first distance is smaller than the second distance.

4. The fixing apparatus according to claim 3 , wherein the first distance is determined according to a mechanical tolerance of the diffuser plate.

5. The fixing apparatus according to claim 3 , wherein the second distance is determined according to an overall expansion coefficient of the diffuser plate.

6. A backlight unit (BLU) comprising:

a housing comprising a frame configured to enclose a plurality of backlight components; and

a fixing apparatus configured to constrain movement of a diffuser plate within the housing, the fixing apparatus comprising,

a receiving portion symmetrically formed at a centrosymmetric line of the diffuser plate, a first pair of edges of the receiving portion setting at either sides of the centrosymmetric line, another edge of the receiving portion cutting across the centrosymmetric line; and

a positioning portion located within the receiving portion and separated from the first pair of edges at a first distance, and separated from another edge of the receiving portion at a second distance, wherein the first distance is smaller than the second distance.

7. The backlight unit according to claim 6 , wherein the receiving portion comprises a fixing hole defined on the diffuser plate, and the positioning portion comprises a positioning pin.

8. The backlight unit according to claim 7 wherein:

the fixing hole has an elliptical cross section with a major axis lying over the centrosymmetric line; and

the positioning pin has a circular cross section with a diameter smaller than a minor axis of the elliptical cross section.

9. The backlight unit according to claim 6 wherein:

the receiving portion comprises a fixing groove defined by the frame; and

the positioning portion comprises a positioning piece projecting from the diffuser plate.

10. The backlight unit according to claim 9 , wherein the positioning piece is configured at a direction of the centrosymmetric line and integrated with the diffuser plate.

11. The backlight unit according to claim 6 further comprising a plurality of diffuser films in contact with the frame, the fixing apparatus also constraining movement of the diffuser films.

12. A displaying device comprising:

a backlight unit (BLU), comprising,

a housing configured to enclose a plurality of backlight components of the BLU, the housing having a frame, and

a diffuser plate placed on the frame and having a fixing apparatus for constraining the movement of the diffuser plate, the fixing apparatus comprising,

a receiving portion symmetrically formed at a centrosymmetric line of the diffuser plate, a first pair of edges of the receiving portion setting at either sides of the centrosymmetric line, another edge of the receiving portion cutting across the centrosymmetric line; and

a positioning portion located within the receiving portion and separated from the first pair of edges at a first distance, the positioning portion separated from another edge of the receiving portion at a second distance, wherein the first distance is smaller than the second distance.

13. The displaying device according to claim 12 , wherein the receiving portion is a fixing hole defined on the diffuser plate, and the positioning portion is a positioning pin.

14. The displaying device according to claim 12 , wherein the receiving portion is a fixing groove defined at the frame, and the positioning portion is a positioning piece projected from the diffuser plate.

15. The displaying device according to claim 14 , wherein the positioning piece is configured at a direction of the centrosymmetric line and integrated with the diffuser plate.