JP3070668B2 - Lighting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device for providing a planar uniform illumination to an object, and more particularly to a lighting device suitable for use as a backlight type illuminating a liquid crystal display or the like from behind. It relates to a lighting device.

[0002]

2. Description of the Related Art In recent years, liquid crystal displays (LCDs) have been widely used in personal computers and word processors. Such a liquid crystal display device needs to be illuminated from behind by a high-luminance backlight of a cold-cathode tube type. FIG. 4 is an exploded front perspective view showing an example of such a conventional lighting device together with a liquid crystal display. 5 and 6 are an exploded rear perspective view and a cross-sectional view of the illumination device according to the conventional example. In these figures, reference numeral 1 indicates a liquid crystal display, and other reference numerals indicate respective components of a backlight type lighting device for illuminating the liquid crystal display 1 from behind. That is, reference numeral 2 denotes a cold cathode tube (fluorescent tube), reference numeral 3 denotes a case, reference numeral 4 denotes a light diffusion plate, and reference numeral 5 denotes an aluminum heat dissipation plate.

In such a structure, light emitted from the cold cathode tube 2 directly reaches the light diffusion plate 4 or reaches the light diffusion plate 4 after being reflected by the case 3. The light diffused by the light diffusion plate 4 illuminates the liquid crystal display 1 as light from a surface light source having uniform luminance. FIG.
As shown in FIG. 2, the case 3 has cutouts 31a, 31b,
, 31f are provided, and the aluminum heat radiating plate 5 is attached. The surface of the aluminum heat radiating plate 5 is coated with white paint in order to prevent a reduction in the reflection efficiency in the notched portion.

[0004]

However, the conventional illuminating device is not always sufficient for obtaining uniform and high-brightness illumination over a wide range. That is, as described above, the heat dissipation plate 5 is painted white to increase the reflection efficiency. However, in such a structure, uneven light is generated in a shadow portion of a component such as a thermistor or a thermal fuse, and the cost increases. Also invited.

In view of the above circumstances, an object of the present invention is to improve the light reflection structure so as to obtain a more uniform and higher-luminance illumination than the conventional device without increasing the cost. Is to provide.

[0006]

SUMMARY OF THE INVENTION The present invention, which relates to the above-described problems, focuses on inserting a film instead of painting, and employs the following technical configuration.
That is, a cold-cathode tube light source, a case that houses the light source and has a structure that reflects light from the light source, and a radiator plate that emits heat generated in the light source and conducted through the notch of the case. , A white film is disposed between the case and the heat sink.

As described above, by disposing a white film between the case and the heat radiating plate as an improvement of the light reflecting structure, the unevenness of light is eliminated and the reflection efficiency is improved.
This is because the film is easier to adapt to the shape of the part attached to the lower part of the light source. It is also achieved at low cost.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an exploded front perspective view showing a lighting device according to an embodiment of the present invention together with a liquid crystal display. FIG. 2 is an exploded rear perspective view of the lighting device according to the embodiment. In these figures, the same components as those in FIGS. 4 to 6 according to the conventional example are denoted by the same reference numerals.

First, although not included in the present invention, unlike the conventional example, as shown in detail in FIG. 3, the shape of the conventional light diffusing plate 4 is improved like a new light diffusing plate 7. . That is, the light diffusion plate portions corresponding to the bent portions 21a, 21b, 21c and the electrode portions 22a, 22b of the cold cathode tube 2 did not exist because they were outside the effective illumination area 40 conventionally.

However, in the effective illumination area 40, the bent portion and the vicinity of the electrode portion become dark because the amount of light emitted from the cold-cathode tube 2 is small. Therefore, a new light diffusion plate 7 is
Projection portions 71a, 71b, 7 corresponding to the bent portion and the electrode portion
1c. Then, a white film or an aluminum film is attached to the surface of the protruding portion on the side of the cold cathode tube, or white printing or silver printing is performed. Note that a white film or white printing is advantageous in terms of cost, and an aluminum film or silver printing is advantageous in terms of a reflection effect.

With such a light diffusion structure,
Light emitted from the bent portion or the vicinity of the electrode portion of the cold-cathode tube 2 is reflected and reaches the effective illumination area 70, and the darkened portion is eliminated.

Next, the features of the present invention, which are different from the conventional example, are as follows.
As shown in FIG. 2, a white film 6 is disposed between the case 3 and the heat sink 5 as a reflection sheet.
As the white film, for example, a film made of polyester and having a thickness of 0.1 mm is preferable. By inserting such a reflection sheet 6, it is not necessary to apply white paint to the aluminum heat sink.

In such a light reflecting structure, even if components such as a thermistor and a thermal fuse are attached to the lower part of the cold cathode tube 2, the film 6 easily adapts to the shape of those components. The unevenness of the light generated in the shadowed portion is also eliminated, and as a result, the reflection efficiency is improved. It is also advantageous in terms of cost.

Although one embodiment of the present invention has been described above, the present invention is of course not limited to this embodiment, and it will be easy for those skilled in the art to devise various embodiments.

[0016]

As described above, according to the present invention,
By improving the light reflection structure, it is possible to obtain illumination that is more uniform and has higher brightness than a conventional illumination device. It is also advantageous in terms of cost.

[Brief description of the drawings]

FIG. 1 is a front exploded perspective view showing a lighting device according to an embodiment of the present invention together with a liquid crystal display.

FIG. 2 is an exploded rear perspective view of the lighting device according to the embodiment.

FIG. 3 is a plan view showing a light diffusion plate according to the embodiment and a light diffusion plate according to a conventional example for reference.

FIG. 4 is an exploded front perspective view showing an example of a conventional illumination device together with a liquid crystal display.

FIG. 5 is an exploded rear perspective view of the lighting device according to the conventional example.

FIG. 6 is a cross-sectional view of the lighting device according to the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display 2 ... Cold-cathode tube (fluorescent tube) 21a, 21b, 21c ... Bending part 22a, 22b ... Electrode part 3 ... Case 4 ... Light diffusing plate 5 ... Aluminum heat dissipation plate 6 ... Reflection sheet (white film) 7 ... Light diffusion plates 71a, 71b, 71c.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields investigated (Int. Cl. ⁷ , DB name) G09F 9/00 304 G09F 9/00 336 F21B 29/00

Claims (1)

(57) [Claims] 1. A cold-cathode tube light source (2), a case (3) containing the light source and having a structure for reflecting light from the light source, and generated in the light source and transmitted through a notch in the case. Radiator plate (5) for releasing heat
And a white film (6) is provided between the case and the heat sink.