JPH0434547Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention is useful for displaying the image plane of a television receiver using a liquid crystal display, for example, since the liquid crystal display is not self-luminous. The present invention relates to an illumination device formed using cold cathode discharge tubes provided as back illumination on the back side of the liquid crystal display in order to make the display easier to see in places.

〓Prior art〓 A conventional lighting device 10 of this type is shown in Fig. 2, in which a plurality of cold cathode discharge tubes 3 are arranged in parallel on a substrate 12 made of metal or the like. 14, and a diffuser plate 5 made of white semi-transparent resin is attached to the front side of the substrate 12 in the form of a lid with a holder 6, etc. By doing this, a substantially uniform surface can be obtained. A light source is obtained on the diffuser plate 5, and this illumination device 1
0 was provided on the back side of a liquid crystal display (not shown) to illuminate the liquid crystal display through transmission.

〓Problems to be solved by the invention〓 The above-mentioned conventional lighting device uses a cold cathode discharge tube 3, and this cold cathode discharge tube 3 has a characteristic that the luminous efficiency changes greatly depending on the temperature of the tube wall. Because of this characteristic, especially in winter, the tube becomes extremely dark, so a heater is attached to the tube wall to maintain the temperature up to about 40 degrees Celsius, which is where maximum luminous efficiency can be obtained. However, keeping the substrate at a temperature higher than the ambient temperature in this way naturally radiates heat to the surroundings, and this means that the substrate 12
This creates a temperature gradient in which the cold cathode discharge tubes 3 arranged in the center are higher in temperature and the peripheral parts are lower in temperature.For this reason, the cold cathode discharge tubes 3 arranged on the outside are dark. As a result, brightness unevenness occurs on the surface of the diffuser plate 5, resulting in a problem of deteriorating display quality.

〓Means for Solving the Problems〓 The present invention is a concrete means for solving the above-mentioned conventional problems. In the illumination device which is provided in the socket and serves as a surface light source, the substrate is provided with a cut groove at a position where the socket is connected, and the width of the cut groove becomes gradually narrower from the end to the center of the socket. By providing a lamp body structure for a cold cathode discharge tube lighting device, which is characterized in that it is formed as follows, the problems that occur in the above-mentioned conventional devices are solved.

〓Example〓 Next, the present invention will be explained in detail based on an example shown in the drawings.

In order to facilitate understanding, parts that are the same as those in the conventional example will be described with the same reference numerals, and descriptions of some overlapping parts will be omitted.

1 is a lighting device according to the present invention, and the lighting device 1 is provided with a substrate 2 made of a member such as metal as in the conventional example, and further includes a socket 4a and a socket 4b. A cold cathode discharge tube 3 is mounted so as to be sandwiched between the substrate 2 and the socket 4a.
Cut grooves are provided as shown in , and these cut grooves 2a to 2
By changing the width of d, the contact area with the socket 4a is adjusted. These kerf grooves 2a to 2d
To explain in more detail the standards established by
As explained in the conventional example, the cold cathode discharge tube 3 is kept warm by a heater.
This heat generation is conducted to the substrate 2 via the sockets 4a and 4b and dissipated into the atmosphere, and a predetermined temperature is reached when the balance between the heating amount of the heater and the heat radiation amount of the substrate 2 is reached. This is given to the cathode discharge tube 3. At this time, if we consider the temperature distribution of each of the cold cathode discharge tubes 3 in more detail, it is obvious that the cold cathode discharge tubes 3 are arranged at the outer end and the center. It tends to be higher due to influences from both sides.

The cut grooves 2a to 2d are formed to correct this tendency, and the widths of the cut grooves are sequentially as follows:
The grooves are formed to become narrower toward the center so that the groove 2a>the groove 2b>the groove 2c>the groove 2d. Although one end is shown in the figure, it goes without saying that the other end and the opposite end have the same configuration. By doing so, the cold cathode discharge tube 3 disposed at the outer end has a reduced amount of heat conduction to the substrate 2 via the socket 4a due to the reduced contact area. As a result, it is possible to maintain the same temperature as the cold cathode discharge tube in the center.

Furthermore, it is preferable that the sockets 4a and 4b be made of a material with good thermal conductivity, since this further ensures the object of the present invention. Note that this illumination device 1 is also provided with a diffuser plate 5 and a holder 6 as in the conventional example, but since they are completely the same as those in the conventional example, illustration and description thereof will be omitted. Also, the number 7 in the figure
The screws shown with numerals are screws for connecting the sockets 4a, 4b and the board 2.

<Effects of the invention> As explained in detail above, according to the invention, the lamp body structure of a cold cathode discharge tube lighting device is provided with a cut groove in the substrate at the position where the socket is connected, and the cut groove is By forming the socket so that its width becomes narrower from the end to the center, the amount of heat conduction to the substrate is changed, and the cold cathode discharge tube in the center and the cold cathode in the end are The display quality of the liquid crystal display is improved by eliminating the temperature difference that occurs in the discharge tubes and adjusting them so that they are at approximately the same temperature, and by eliminating the uneven brightness that occurs on the diffuser plate without using any special electrical circuits. This has the excellent effect of improving

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing essential parts of an embodiment of the lamp body structure of a cold cathode discharge tube lighting device according to the present invention, and FIG. 2 is a perspective view showing a conventional example. 1...Lighting device, 2...Substrate, 2a to 2d...
Cut groove, 3...cold cathode discharge tube, 4a, 4b...socket.

Claims (1)

[Scope of utility model registration request] In an illumination device in which a plurality of cold cathode discharge tubes are arranged in parallel and used as a surface light source provided on a single substrate via a socket, a cut groove is provided in the substrate at a position to which the socket is connected. . A lamp body structure for a cold cathode discharge tube lighting device, wherein the kerf is formed so that its width becomes narrower from the end to the center of the socket.