Direct type back light device and frame thereof

A frame for a direct type back light device is provided. The frame includes a base and a plurality of side-plates. The base has a groove and an opening. The groove has a first end and a corresponding second end. The side-plates are respectively disposed on a periphery of the base so that a first slit and a second slit are formed at positions corresponding to the first and the second ends. The first and second slits have different sizes.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to Taiwan Patent Application No. 091122079 entitled “Direct Type Back Light Device and Support Frame Thereof”, filed Sep. 25, 2002.

1. Field of Invention

The present invention generally relates to a direct type back light device and a frame thereof and, more particularly, to a direct type back light device with a frame having heat dissipation design.

2. Background of the Invention

Liquid crystal display (LCD) devices characterized by compact size and excellent image qualities have gradually taken the place of conventional cathode ray tube (CRT) devices because it has been difficult to miniaturize the volume and the weight of CRT devices. The LCD device itself does not emit light, and thus a light source is required. The light source, which irradiates the LCD device, generally refers to a back light device.

The back light devices are generally classified into two types: an edge type and a direct type. The edge type back light device includes a lamp typically arranged on an edge side of the LCD device, a light guide plate positioned next to the lamp, a diffusion sheet disposed above the light guide plate, and a reflection plate disposed below the light guide plate. The light guide plate can uniformly distribute rays irradiated from the lamp to the LCD panel. The reflection plate reflects rays back to the diffusion plate so that most of the rays from the lamp can incident to the diffusion plate.

Comparatively, the direct type back light device does not require a light guide plate. Linear light is directed to the LCD display from a light source via a diffusion plate. Therefore, the direct type back light device is widely used in large sized LCD devices because it has high light transmission and does not have a limitation in the size of the display area.

Conventional direct type back light devices lack designs for dissipating heat. Therefore the heat generated by the lamp easily overheats the back light device, reduces its performance, and more particularly, damages the back light device. Therefore, there is a need to provide a frame for a back light device to improve the heat dissipation ability.

SUMMARY OF THE INVENTION

It is one aspect of the present invention to provide a frame having heat dissipation ability for a direct type back light device. The frame includes a base and a plurality of side-plates. The base has a groove and an opening, and the groove has a first end and a corresponding second end. The side-plates are respectively disposed on a periphery of the base so that a first slit and a second slit are formed at positions corresponding to the first end and the second end of the groove. The first and second slits have different sizes.

In an embodiment, the groove is a trapezoid groove, and the first and second slits are in different sizes allowing air to flow through. Furthermore, the base has a first edge, a second edge, and a third edge, and the side-plates include two first side-plates and a second side-plate. The first side-plates are respectively disposed on the first and the third edges, and the second side-plate is disposed on the second edge. Each first side-plate has a vent for dissipating heat, and the second side-plate has a hole for allowing a cable to pass through.

It is another aspect of the present invention to provide a direct type back light device. The direct type back light device includes the frame described above, a lamp set, and a diffusion plate. The base further includes at least one retainer and at least one supporter. The retainer connects to the lamp set. The retainer is disposed on the base so as to allow the lamp set to be disposed in the frame and a predetermined distance is formed between the lamp set and the second side-plate. The supporter supports the diffusion plate so as to allow the diffusion plate to be disposed above the lamp set.

DETAILED DESCRIPTION

Referring toFIGS. 1A to 1D, in one embodiment of the present invention, a frame10for a direct type back light device is provided. The frame10includes a base12and a plurality of side-plates. The base12has a groove122and an opening124for dissipating heat. The groove122has a first end122A and a corresponding second end122B. In this embodiment, the side-plates include two first side-plates14and two second side-plates16respectively disposed on a periphery of the base12, so that a first slit1220and a second slit1222are formed at positions corresponding to the first end122A and the second end122B of the groove122.

The groove122can be a trapezoid groove or a triangle groove. When the groove122is a trapezoid groove, the first and second ends122A and122B are parallel.

The base12has a first edge131, a second edge132, a third edge133, and a fourth edge134. The two first side-plates14are respectively disposed on the first and the third edges131and133so that the first slit1220and the second slit1222with different sizes are formed corresponding to the first and the second ends122A and122B, as shown inFIGS. 1C and 1D. In this embodiment, the first slit1220(as an inlet) is a smaller slit and the second slit1222is a larger slit so as to allow air to flow into the frame10. The air carrying heat generated by the back light device flows out of the frame10through the slit1222(as an outlet).

As shown inFIG. 1A, in this embodiment, the base12is in a rectangular shape, and has eight trapezoid groove122and twelve trapezoid opening124. The openings124are arranged in pairs and disposed between every two adjacent grooves122. The first side-plates14are respectively disposed on the first and the third edges131and133so as to form eight inlets (slits1220) and eight outlets (slits1222) on the first and second ends122A and122B. The first side-plate14has at least one vent140for dissipating heat. The vents140can be disposed at ends of the first side-plate14. The second side-plates16are respectively disposed on the second edge132and the fourth edge134. Each second side-plate16has at least one hole160for allowing a cable to pass through. For example, a cable (not shown) connected to a lamp set can pass through the holes160on the frame10. Furthermore, the hole160can also serve as a vent for allowing air to flow through.

Referring toFIG. 2, in another embodiment, a direct type back light device100is provided. The direct type back light device100includes the frame10described above, a lamp set20disposed in the frame10, and a diffusion plate30disposed above the lamp set20. The frame further includes at least one retainer126for connecting the lamp set20. The retainer126is disposed on the base12so that a predetermined distance is formed between the lamp set20and the second side-plate16. In such an arrangement, the heat generated at two ends of the lamp set20can be dissipated through the vents140of the first side-plates14. The base12further includes a supporter128for supporting the diffusion plate30, so that lights emitted from the lamp set20can be uniformly diffused.

Furthermore, the frame10further includes a cover plate positioned above the groove122and the opening124to improve heat dissipation by convection. The cover plate40can be made of metal, such as aluminum.

It is noted that the scope of the invention is not limited to those described in the embodiments even though the numbers and shapes of the groove122, the opening124, the first and second slits1220and1222(inlet/outlet), the retainer126, the supporter128, and the hole160are illustrated specifically. Furthermore, the backlight device100can further includes other components that are not described in the embodiments, such as a reflection sheet disposed under the lamp set20in the frame10.