JPH0451935B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a tube-shaped light bulb that eliminates uneven illumination by surrounding a tube-shaped bulb having an infrared reflective film with a diffusely transparent outer bulb.

[Technical background of the invention and its problems]

A halogen light bulb for copying machines has a plurality of filaments connected in series via short-circuit wires sealed in a tube-shaped bulb, and is combined with a reflector to illuminate the surface of a document. However, since halogen bulbs emit a large amount of infrared rays as well as visible light, there is a risk of burning out the document.Furthermore, since the filaments are arranged at a distance, there is also a drawback that illumination unevenness occurs on the surface of the document.

In response to this, the applicant first provided a visible light transmitting infrared reflective film on at least one of the inner and outer surfaces of the bulb to reflect the infrared rays of the light emitted from the filament and return it to the filament, thereby heating it. We proposed a tube-shaped light bulb that has improved efficiency and emits less infrared radiation.

Additionally, in order to eliminate uneven illumination, we considered providing a light-diffusing film on the outer surface of the bulb, but in this case there is a risk that the bulb would overheat. In other words, if the outside of the bulb is concentrically surrounded by a diffused light-transmitting outer tube, the bulb has an exhaust pipe protruding from its side, so the outer tube becomes larger in diameter and the copying machine itself becomes larger. In addition, there are also disadvantages of decreased light convergence and increased optical loss.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a tube-shaped light bulb that is small and has no uneven illuminance.

[Summary of the invention]

A visible light transmitting and infrared reflecting film is formed on at least one of the inner and outer surfaces of a tubular valve in which a filament is sealed and an exhaust pipe is protruded from the side surface, and a diffused light transmitting outer tube surrounds the side surface of the valve from the outside of the exhaust pipe. ,
This outer tube has a small diameter by being eccentrically positioned so that its inner surface approaches the side surface of the valve opposite to the exhaust pipe.

[Embodiments of the invention]

The details of the invention will be explained by means of illustrated embodiments. The figure shows a halogen light bulb for a copying machine to which the present invention is applied, and in the figure, 1 is a straight tube-shaped transparent bulb made of heat-resistant glass such as quartz glass, and 2 is an exhaust pipe protruding from the side of the bulb 1. , 3,3 is valve 1
4, 4 are molybdenum introducing foils embedded in these sealing portions 3, 3, respectively, and 5, 5 are connected to these introducing foils 4, 4 to form a valve 1. The lead-in wires 6, 6... introduced into the lead-in wires 5, 6 are connected in series via the short-circuit wires 7, 7...
5, a plurality of tungsten filaments located at the center line of the bulb 1; 8, a visible light transmitting and infrared reflecting film formed on the outer surface of the bulb 1; 9;
9 is an annular support supported by the sealing parts 3, 3 of the bulb 1; 10 is a diffusely transparent outer tube supported by these supports 9, 9 and surrounding the side surface of the bulb 1 from the outside of the exhaust pipe 2; , 11, 11 are terminals connected to the introduction foils 4, 4 and attached to the end faces of the sealing parts 3, 3.
In this way, the required halogen is sealed inside the bulb 1 along with an inert gas such as argon.

The infrared reflective film 8 is made by alternately layering 7 to 8 layers of a metal oxide layer with a high optical refractive index such as titanium oxide and a metal oxide layer with a low optical refractive index such as silica, and transmits visible light well. , has the property of reflecting infrared rays well.

The outer tube 10 is made of transparent glass, has a straight tube shape, and has at least one of its inner and outer surfaces formed into a light-diffusing uneven surface by means of acid treatment, honing, or the like. On the opposite side of the exhaust pipe 2, the outer pipe 10 is eccentrically located close to the side surface of the valve 1. Note that the support body 9 may have a ventilation structure or a closed structure.

Next, the function of this light bulb will be explained. When this light bulb is energized, the filaments 6, 6... reflect a large amount of infrared rays as well as visible light. Then, the infrared rays are reflected by the infrared reflecting film 8 and the filament 6,
6... returns to heat it, which helps improve efficiency. Further, the visible light passes through the infrared reflecting film 8 and enters the outer tube 10, where it is diffused and radiated to the outside world. Therefore, the emitted light from this light bulb has little infrared content, and since the light is scattered,
Even though the filaments 6, 6, . . . are spaced apart, the illuminance distribution is uniform. Furthermore, the outer tube 10
is separated from valve 1, so valve 1 does not get too cold even in winter or in cold regions.
The valve 1 will not overheat even in summer or at high temperatures.

In particular, in this light bulb, the outer tube 10 is located eccentrically with respect to the bulb 1, so even though the exhaust pipe 2 protrudes from the side of the bulb 1, the outer tube 10 extends from the outside of the exhaust tube 2 to the bulb 1. An outer tube 10 surrounds the side surface of the valve 1 and is close to the side surface of the valve 1 on the opposite side of the exhaust pipe 2. Therefore, in this light bulb, the outer bulb 10 can be made small in diameter and its surface area can be made small, so that even when a sufficient light diffusion effect is exerted, light loss can be reduced.

When this light bulb is used as a light source for a copying machine, the center of the outer bulb 10 is positioned at the center or focal point of the quadratic curved reflector 12, as shown in the third figure, and the exhaust pipe 2 of the bulb 1 is Combine so that it is on the light emitting side. In this case, the light distribution becomes slightly oval as shown in the fourth figure. Then, in this case, the outer tube 10
constitutes a secondary light emitting surface, so if the outer bulb 10 is small, the convergence of reflected light will be better and the light will be brighter. Furthermore, since the outer tube 10 is small, the reflecting plate 12 can be small, and therefore the copying machine itself can be configured to be small.

Next, another embodiment is shown in FIG. This one has an outer tube 10 shaped like an oval tube, and a cylindrical valve 1.
are arranged concentrically in a semicircular portion of the outer tube 10, and the exhaust pipe 2 is located within the semicircular portion. Note that 6 is a filament and 8 is an infrared reflective film. This also has the same effect as the first embodiment described above.

Therefore, in the above embodiment, the outer tube is made of transparent glass, and at least one of the inner and outer surfaces thereof is formed with a light-diffusing uneven surface, but in the present invention, at least one of the inner and outer surfaces of the outer tube made of transparent glass is formed. A light-diffusing film may be formed on the outer tube to impart light-diffusing properties, and the outer tube may be made of light-diffusing glass such as opalescent glass or crystallized glass. Further, the glass of the outer tube may be made of infrared absorbing glass or colored glass, and the point is that the outer tube only needs to have diffused light transmittance. Then, colored powder or the like may be mixed into the light-diffusing film so that the film also has other properties.

Further, in the present invention, the above-mentioned effects can be obtained if the infrared reflective film is formed on at least one of the inner and outer surfaces of the bulb. Furthermore, only one filament may be provided, and in this case as well, the light scattering properties of the outer bulb can be used to reduce the unevenness of illuminance on the irradiated surface due to the infrared reflective film and the unevenness of illuminance due to the filament image that occurs when combined with a reflector. It can be resolved.

Further, in the present invention, the outer tube may be made of a transparent synthetic resin, and at least one of its inner and outer surfaces may be provided with a prism cut to impart light-diffusion properties. Good too,
In this case, it is necessary to improve ventilation within the outer tube to prevent heat loss in the outer tube.

Note that the present invention can be applied not only to halogen light bulbs but also to ordinary light bulbs and has similar effects. The filament then does not have to be in the center of the valve.

[Effect of idea]

The tube-shaped light bulb of the present invention has a transparent tube-shaped bulb with a filament sealed and an exhaust pipe protruding from the side surface.A visible light-transmitting infrared reflecting film is provided on at least one of the inner and outer surfaces of the tube-shaped transparent bulb, and the exhaust pipe is provided with a diffused light-transmitting outer tube. This outer tube surrounds the side of the valve from the outside and is eccentrically positioned so that its inner side approaches the side of the valve opposite to the exhaust pipe, thereby reflecting infrared rays and heating the inside of the valve. This helps improve efficiency and reduces infrared rays in the emitted light, and the outer tube scatters the emitted light to make the illuminance distribution uniform, and the outer tube is made compact to reduce optical loss. Also when used in combination with a light source for a copying machine, there is an advantage that the reflecting plate and the copying machine main body can be made compact.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of one embodiment of the tube-shaped light bulb of the present invention, FIG. 2 is a cross-sectional view similarly taken from another direction, and FIG.
The figure is a layout model diagram when this example light bulb is used in combination with a reflector, Figure 4 is the same light distribution diagram, and Figure 5 is the same diagram.
The figure is a sectional view of another embodiment. 1... Valve, 2... Exhaust pipe, 6... Filament, 8... Infrared reflective film, 10... Outer tube.

Claims (1)

[Scope of Claims] 1. A tubular transparent bulb having a sealed filament and an exhaust pipe protruding from the side surface, a visible light transmitting infrared reflecting film formed on at least one of the inner and outer surfaces of the bulb, and the above exhaust pipe. a diffusely transparent outer tube that surrounds a side surface of the bulb from the outside of the tube, and the outer tube is eccentrically positioned so that its inner surface approaches the side surface of the bulb opposite to the exhaust pipe. A tube-shaped light bulb featuring 2. The tube-shaped light bulb according to claim 1, wherein the outer bulb is made of a transparent material and at least one of the inner and outer surfaces is formed with a light-diffusing uneven surface. 3. The tube-shaped light bulb according to claim 1, wherein the outer bulb is made of a transparent material and has a light-diffusing film formed on at least one of its inner and outer surfaces. 4. The tube-shaped light bulb according to claim 1, wherein the outer bulb is made of a diffusely translucent material.