JPS63271861A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To make light a plane optical source with good efficiency along with striving for a low cost by processing the inside of a fluorescent tube, so as to change optical distribution on the inner surface of a glass tube. CONSTITUTION:In the application process of a phosphor emulsion to the inner surface of a glass tube 1, the thickness of a phosphor film 4 is made unequal, being t2>t1 by performing application by keeping the glass tube 1, for instance, sideways or slantwise. Or, optical distribution on the glass tube section is intensified in the direction of a reflection plate by performing printing 5 on the inner surface of glass tube for making the optical distribution unequal before applying the phosphor emulsion. Thereby, the distribution of light on a dispersion plate can be made in about equal brightness and accordingly an optical source can be formed in a plane.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light source for a backlight system for a liquid crystal display device, and more particularly to a fluorescent lamp suitable for reducing the thickness of the entire system and making it a flat light source.

[Conventional technology]

Conventionally, as a measure to prevent uneven brightness on the light emitting surface of a backlight system, as described in JP-A-55-133008, a pattern film to prevent uneven brightness was installed between the light source and the light emitting surface, or a pattern film was installed between the light source and the light emitting surface. A method was used to print a pattern on the lamp surface to prevent uneven brightness.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology has problems in efficiently converting the light emitted from the light source into a flat light source, and in addition, in terms of high cost due to an increase in the amount of work, it is impossible to achieve higher efficiency and lower cost. It was considered an issue.

[Means for solving problems]

The above purpose is to change the phosphor (emulsion) coating method during the fluorescent lamp manufacturing process, or to print, process, or coat the inner surface of the glass tube with a material that changes the light distribution in advance. This is achieved by changing the distribution.

[Effect]

By changing the light distribution of the fluorescent lamp by modifying the inner surface of the fluorescent lamp, efficiency can be increased by eliminating reflections from the outside of the fluorescent lamp glass tube and loss during transmission. Furthermore, since the light distribution is changed during the fluorescent lamp manufacturing process, cost increases can be kept to a minimum.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

In the fluorescent lamp manufacturing process, for example, when manufacturing a straight tube type fluorescent lamp, there is a step of applying a fluorescent emulsion as shown in FIG. 2 to the inner surface of a glass tube 1 as shown in FIG. 1, and then coating a fluorescent film 4 thereon. In the conventional coating process, the fluorescent emulsion is coated with the glass tube 1 upright, so the thicknesses ti and tz of the fluorescent film 4 are approximately equal to the cross section of the glass tube. Therefore, when a fluorescent lamp is turned on, its light distribution is approximately equal in all directions with respect to the cross section of the glass tube, and the light distribution characteristic 6 shown in FIG. 4 is obtained. Therefore, as shown in FIG. 6, in the backlight system combined with the reflector plate 8 and the diffuser plate 9, the light emitting surface brightness distribution 10 on the diffuser plate 9 is such that the light emitted from the fluorescent lamps 12 is extremely high on the upper surface of the fluorescent lamps. Therefore, it tends to be unsuitable as a flat light source.

Therefore, in the present invention, in the step of applying the fluorescent emulsion to the inner surface of the glass tube 1, the coating is performed while the glass tube 1 is tilted horizontally or diagonally, so that the fluorescent film 4 can be formed as shown in FIG. The thickness is made non-uniform and tz>tz. Alternatively, before applying the fluorescent emulsion, by printing 5 on the inner surface of the glass tube to make the light distribution non-uniform, as shown in FIG. The light distribution 7 is made stronger in the direction of the reflecting plate 8. As a result, the light distribution on the scattering plate 9 obtains a nearly uniform brightness as shown in the brightness distribution 11 shown in FIG. 7, and thus a planar light source is achieved.

Note that the printing 5 shown in FIG. 3 is a part for obtaining the light distribution as shown in FIG. 5, and the same result can be obtained with a linear, polygonal, or irregular shape. Here, to increase efficiency,
For printing, it is effective to use silver or vapor deposition such as AQ, or even a titanium oxide film. In addition to the printing method, the object of the present invention can also be achieved by utilizing light refraction and diffusion through dimple-like processing.

〔Effect of the invention〕

According to the present invention, since the light distribution of the fluorescent lamp can be changed on the inner surface of the glass tube, the luminous efficiency on the plane light source surface with respect to power consumption is higher than that of the film for preventing uneven brightness or the printing method on the outer surface of the fluorescent lamp. In addition, since the non-uniform light distribution described above can be achieved as part of the fluorescent lamp manufacturing process, it is effective in that it can be done at a lower cost than the above-mentioned measures to prevent uneven brightness.

[Brief explanation of the drawing]

FIG. 1 is a glass tube for a straight fluorescent lamp, FIG. 2 is a partial cross-sectional perspective view of a fluorescent lamp according to an embodiment of the present invention, and FIG. 3 is a glass tube for a fluorescent lamp according to an embodiment of the present invention. 4 is a cross-sectional light distribution characteristic diagram of a conventional lamp, FIG. 5 is a cross-sectional light distribution characteristic diagram of a lamp according to an embodiment of the present invention, and FIG. 6 is a cross-sectional diagram of a conventional lamp. FIG. 7 is a correlation diagram between a cross section of a backlight system and luminance characteristics of a light emitting surface when the lamp of the present invention is used. 1... Glass tube, 4... Fluorescent film, 5... Printing, 6
゛...Conventional lamp light distribution characteristics, 7...Lamp light distribution characteristics of the present invention, 8...Reflector plate, 9...Diffusion plate, 1o.
... Luminance characteristics of the light emitting surface when using a conventional lamp, 1
1... Luminance characteristics of the light emitting surface when using the lamp of the present invention, 12... Light emission from a fluorescent lamp. Agent: Patent attorney Katsuma Ogawa,・'Pa''-)!7Pa,.

Claims (1)

[Claims] 1. A fluorescent lamp as a light source for a backlight system of a liquid crystal display, characterized in that the inner surface of the fluorescent tube is processed to provide non-uniform light distribution. 2. The fluorescent lamp according to item 1, in which the coating amount of the phosphor emulsion is made non-uniform in the cross-section of the fluorescent tube and the light distribution is changed to create a flat light source. 3. The fluorescent lamp according to item 1, wherein the inside of the discharge glass tube of the fluorescent lamp is printed, dimpled, or coated with other materials such as titanium oxide to provide non-uniform light distribution.