JPH0432498B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a fluorescent lamp, and particularly to a so-called aperture type fluorescent lamp (hereinafter abbreviated as a fluorescent lamp).

Conventionally, an aperture type fluorescent lamp is a light source whose purpose is to obtain uniform linear high luminance, and has been used as a light source for copying machines, facsimile machines, optical printers, and the like. As shown in Figures 1 and 2, its structure is such that a phosphor 2 coated on the inner surface 1 of a glass tube of a fluorescent lamp is removed in a slit shape in the longitudinal direction of the tube to form an aperture 3. It was hot.
However, since the luminance distribution in the longitudinal direction of the light obtained from the aperture 3 has the property that the luminance gradually decreases as it moves away from the center, as shown in Fig. 3, When a long linear light is required, the brightness at the end of the linear light is reduced, and the drawback is that high uniformity of brightness in the longitudinal direction cannot be obtained. Conventionally, in order to deal with this drawback, a method of increasing the absolute length of the fluorescent tube has been taken, but this has resulted in problems of increasing the size and cost of the device.

The present invention is characterized in that both ends of the aperture portion of the fluorescent tube where linear light is not used are covered with a light reflecting film (light reflecting member). The objective is to improve the uniformity of brightness in the length direction of linear light.

An embodiment of the present invention will be described with reference to FIG.

When linear light having the length shown by 4 is required, by providing a light reflection film 5, the light that conventionally leaked from the aperture as unnecessary light is reflected by the light reflection film and re-enters the inside of the fluorescent tube. After being diffusely reflected inside the tube, the light is focused at the end of the open aperture section 3, improving the brightness.

Using a silver thin film formed by a silver mirror reaction method as a light reflecting film, this invention was carried out using an aperture-type fluorescent lamp with a tube length of 37 cm, a tube diameter of 16 mm, and an aperture width of 3 mm. The ratio of brightness in a 10 cm area was 85% as shown in Figure 3 in the past, but after implementing the invention, it became 95% as shown in Figure 5, resulting in linear light with an almost uniform brightness distribution. was gotten.

As described above, the present invention has a great effect in making uniform the luminance distribution of linear light obtained from an aperture type fluorescent lamp. In addition, in order to obtain linear light with the same uniformity as conventional aperture-type fluorescent lamps, the tube length needs to be shorter than that of conventional aperture-type fluorescent lamps, which results in smaller equipment, lower power consumption, and lower This has a great effect on reducing costs.

Note that the material of the light reflective film in the structure of the present invention is not limited to the above-mentioned silver thin film, but the same effect can be obtained by using an aluminum reflective film or white paint.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the structure of a conventional aperture type fluorescent lamp. FIG. 2 is an external view of a conventional aperture type fluorescent lamp. FIG. 3 is a graph showing the luminance distribution of a conventional aperture type fluorescent lamp. FIG. 4 shows an embodiment of the present invention. FIG. 5 is a graph showing the luminance distribution of an aperture type fluorescent lamp after implementing the present invention. 1... Fluorescent tube, 2... Fluorescent material, 3... Aperture, 4... Required linear light range, 5... Light reflecting film.

Claims (1)

[Scope of Claims] 1. In a fluorescent lamp having an aperture portion in which a phosphor formed on the inner surface of a glass tube is removed in the longitudinal direction of the fluorescent tube in the form of a slit, an end portion of the fluorescent tube in the aperture portion The fluorescent lamp is characterized in that a light reflecting member is formed to prevent light from leaking at the end of the aperture portion and to allow the light to re-enter the inside of the fluorescent tube.