JPS62183484A - Fluorescent lamp back light - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a backlight for a liquid crystal, and in particular, a fluorescent lamp is used as the backlight to increase the brightness of the liquid crystal even when the liquid crystal size becomes large. The present invention relates to a fluorescent lamp backlight suitable for reducing unevenness in brightness.

[Conventional technology]

Conventionally, it has been known to install a fluorescent lamp under a liquid crystal and use it as a backlight, and in this case, the technical problem was particularly how to suppress unevenness in brightness. For this reason,
As described in Japanese Patent Application Laid-open Nos. 55-133008 and 60-75909, the problem of brightness unevenness is being solved by taking measures to suppress brightness unevenness by installing a brightness unevenness removing plate directly above the lamp.

[Problem that the invention seeks to solve]

However, now that liquid crystals are becoming larger and color, and extremely high-density liquid crystals such as TgT liquid crystals are being actively developed (requirements for backlighting are becoming higher brightness than before, and TPT liquid crystals The light transmittance is very poor (approximately 3 to 6%), which is natural.

In this case, the problem is that high brightness cannot be obtained unless the backlight is given a higher output than before, and if a commercially available lamp such as FL10W%F'L15W is used, the backlight becomes thicker and the liquid crystal becomes thinner. It destroys that image. In addition, two small lamps are placed side by side,
Lighting multiple lights (three lights) would require a corresponding number of lighting circuits, which was inappropriate in terms of cost.

Therefore, an object of the present invention is to improve the points that have not been taken into account in the conventional technology as described above, and to improve the problem without changing the thickness of the backlight even when the LCD screen becomes larger.
To provide a fluorescent lamp backlight with a structure that allows for obtaining a backlight with higher brightness than before and that allows for easy replacement of the fluorescent lamp used for the backlight.

[Means for solving problems]

In order to achieve the above objective, we first assumed that there must be only one fluorescent lamp, and in order to obtain high brightness with one fluorescent lamp, reduce uneven brightness, and take into account replacement. I thought it would be a good idea to process a single light lamp into various shapes. Possible shapes for this are U-shape, V-shape, W-shape, double V-shape, triple U-shape, etc.
With this shape, one lamp can be seen as two, four, or six lamps, and since there is a lamp input end in only one direction, we thought it would be easy to replace.

Also, even if the shape cannot be expressed in other words, it can have the same shape (all can achieve the same effect).

However, the S-shaped one is inferior in that the input ends are on both sides and the input ends are only in one direction.

Further, in each of the above shapes, only one lamp lighting device is required, and the cost is much lower than that of multiple lamp lighting.

[Effect]

By processing a single fluorescent lamp into an 8-shape, a U-shape, a V-shape, a W-shape, etc., there is the advantage that the length of light emission can be made longer and longer without changing the tube diameter or space of the lamp. Furthermore, increasing the emission length means that the average brightness of the surface when viewed as a backlight increases in proportion to the emission length. In addition, by making it U-shaped, W-shaped, etc., the number of lamps appears to be 2 when viewed from above the liquid crystal display.
This increases the number of lines to four, and the brightness of the four corners of the LCD screen, where the brightness is the lowest, can be increased by the increased number of lines, which reduces unevenness in brightness, resulting in a double benefit.

Furthermore, as mentioned earlier, only one lamp lighting device is required as in the case of conventional one-lamp lighting, so the space for the entire backlight can be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. Figure 1 shows a structure in which a fluorescent lamp 3 processed in a U half is used as a backlight for a 10-inch liquid crystal display. Light guide box 2 size is 220mm x 17
The dimensions were 0 mm x 30 mm.

In addition, the outer diameter of the tube used for the U-shaped lamp 3 is 15.5 mm.
It is. In addition, the actual length 1 inside the box 2 of the lamp 3 (E, tube diameter D1, lamp surface average brightness L1, light utilization rate a1 of the light box 2, transmission of the diffuser plate 1 -?' bs
If the area of the top surface of the light guide is A1 and the required brightness of the light guide is LG, then L X a X yr X D X j X b =
It is found by A X L G.

In this example, L=15000 nt% a=0.5, D
=15.5mm b=0.9, A=37400mm
When 2LG=4000 nt, it becomes as follows, but since it is U-shaped, it is actually 420 nt.

As a result, the surface average brightness on the light guide is 1:
t3500nt was obtained, which was exactly as calculated.

Moreover, the brightness unevenness in this case, defined as maximum brightness/average brightness to minimum brightness/average brightness, was about 135% to 62%, and a fairly uniform flat light source was obtained.

Milky white acrylic was used for the diffuser plate 1, but if a diffuser plate with an even greater diffusion effect (transmittance becomes worse) is used, the average luminance will be lower, but unevenness can be reduced.

In addition, an aluminum board was used for the light box 2, and a commercially available lacquer paint mortar was used for the inner surface.

A 12-stone bush-pull inverter circuit was used for the lamp lighting device, and the lamp power consumption was 8 watts.The phosphor used was a 3-wavelength RGB phosphor, and the color temperature was 5000.

〔Effect of the invention〕

According to the present invention, by lighting one fluorescent lamp with one lighting circuit, the surface brightness of the light guide can be increased without changing the thickness of the backlight even when the screen size of the liquid crystal increases. It also has the effect of reducing brightness unevenness,
In addition, in order to easily replace the lamp, the problem can be solved by making the input end to the lamp only in one direction.

Furthermore, if the jig 4 and the like for fixing the lamp are made of a material with good reflection, taking into account the reflection of light in the part that will be inside the light box, the brightness can actually be increased by several percent.

[Brief explanation of drawings]

FIG. 1 is an assembled structural diagram of an embodiment of the present invention. 1 Niacrylic diffuser plate, 2 Nilight box, 3: Figure 8 fluorescent lamp, 4: Lamp fixing jig. 7th Ward 4 Ranf'l Tsukasa Jin 5 Breasts

Claims (1)

[Claims] 1. In a device using a fluorescent lamp as a backlight for a liquid crystal display, the fluorescent lamp used as the backlight includes at least one curved non-linear portion. Fluorescent lamp backlight. 2. The fluorescent lamp backlight according to item 1, wherein the input end of the fluorescent lamp is located below the liquid crystal, and power is supplied from one direction.