JPS61225757A - Tubular type bulb - 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 TECHNICAL FIELD OF THE INVENTION The present invention relates to a high-efficiency light bulb with improved light distribution, and is particularly suitable as a light source for copying machines. [Technical Background of the Invention] Conventional halogen light bulbs for copying machines include a tube-shaped bulb made of quartz glass or the like with a filament arranged along the center line, and at least one of the inner and outer surfaces of the bulb is made of high refractive material made of titanium oxide or the like. It is equipped with a visible light transmitting infrared reflective film made by alternately layering 9 to 15 low refractive index layers and low refractive index layers made of silica, etc. The visible light emitted from the filament is transmitted through the infrared reflective film. The infrared rays are reflected by the infrared reflective film and returned to the filament to heat it. As a result, it has the advantage of high efficiency and little infrared radiation. [Interlayer points in the background art] When a large original is used, a low-illuminance area appears in the area a few degrees closer to the center from the edge of the original, and as a result, the underexposed area appears as a dark line on the side edge of the copy paper. It appears as [Object of the Invention] An object of the present invention is to provide a tube-shaped light bulb that has a uniform illuminance distribution at the side edge of the illuminated surface. [Summary of the Invention] The first aspect of the present invention is to crystallize at least one of the metal compounds constituting the visible light transmitting infrared reflective film at the end of the tube, thereby imparting light scattering properties without losing infrared reflective ability. This scatters the emitted light from the end of the tube without reducing luminous efficiency, and makes the illuminance distribution uniform at the side edges of the irradiated surface. The second aspect of the present invention provides the same effects as the first aspect by providing a light scattering film overlapping the visible light transmitting infrared reflective film on the radiation side at the end of the tube. [Embodiments of the Invention] Details of the present invention will be explained with reference to the illustrated embodiments. Embodiment] In this embodiment, the tube end portion of the visible light transmitting and infrared reflecting film also has visible light diffusing properties, and the details thereof are shown in FIG. ■ is a straight tube bulb made of transparent quartz glass, ■ is a visible light transmitting infrared reflective film formed on the outer surface of this bulb (■),
2a) is the tube end portion of this reflective film ■, 2) and 2) are the sealing parts formed by crushing and sealing both ends of the bulb ■, and 2a and 2 are the insides of these sealing parts (a) and 2). embedded molybdenum introduction foil,
0. ■ is an inner conductor connected to these introduction foils ■, ■ and introduced into the bulb ω, ■ is a tungsten coil filament installed between these inner conductors 0, 0, (c), 0...
is the anchor that supports the filament ■, ■, ■ is the introduction foil■
, ■ are electrically connected to the terminals installed on the end faces of the sealing parts (A) and (A). Then, the required halogen is sealed inside the bulb ω along with an inert gas such as argon. As shown schematically and enlarged in FIG. 2, the visible light transmitting infrared reflecting film (2) has a high refractive index layer (21) made of a metal compound such as titanium oxide or tantalum oxide on the outer surface of the bulb ω.
It consists of 9 to 15 alternate layers of low refractive index layers (22) (upper right rehatching) made of silica, magnesium fluoride, and other metal compounds (upper left rehatching), and uses light interference to detect visible light. It transmits infrared rays and reflects infrared rays. Then, the tube end portion (2
Particularly, a) and (2a) suitably contain microcrystals of these metal compounds in the high refractive index layer (21a) to have visible light diffusing properties. Thus, crystallization of these metal compounds within the low refractive index layer (22a) is not necessarily necessary. Various methods are known for forming such a visible light transmitting infrared reflecting film (1), and examples thereof are as follows. First, an organometallic compound such as tetralinepropyl titanate is applied to the entire outer surface of the valve ■ to a predetermined thickness and dried.
A high refractive index layer (21
) to form. Next, another organometallic compound such as ethyl silicate is applied to the surface of this layer (21) to a predetermined thickness, dried, and fired to form a low refractive index layer (22) made of oxides of these metals. do. In this way, the high refractive index layer (21) and the low refractive index layer M (22) are alternately formed to form a visible light transmitting infrared reflecting film (2). Next, the tube end portion (2a) of this infrared reflective film (2) is heated at a high temperature with a burner flame for an appropriate period of time to crystallize the metal compound. In FIG. 2, scattered dots indicate crystallization. If crystallization progresses excessively, the infrared reflecting ability is lost, so the heating temperature and heating time can be adequately controlled. Next, the operation of the light bulb of this embodiment will be explained. Both terminals 0,0
When electricity is applied between them, the filament (■) generates heat and emits a large amount of infrared rays along with visible light. Of these lights, visible light is reflected by infrared rays,
(2a) and is emitted to the outside, and the infrared rays are reflected by the infrared reflection Jul (2) and (2a) and return to the filament (2) to heat it and improve the luminous efficiency. Since the tube end portion (2a) of the infrared reflective film (2) has a light-diffusing property, the visible light that passes through this portion (2a) is appropriately scattered, and as a result, the desired illuminance at the side edge of the irradiated surface is With a slightly wider range. Even if there are areas with low luminous intensity near the end of the bulb, the illuminance is averaged on the irradiated surface, eliminating dark areas. This state is shown in Figure 3, where the horizontal axis represents the position along the pipe length and the vertical axis represents the illuminance.
The broken lines indicate the illuminance distribution of the conventional example which does not have light scattering properties at the tube end. This figure also shows that the desired illuminance range of the light bulb of this embodiment is wide and there is no dark portion at the tube end. Example 2 In this example, as shown in FIG. 4, a visible light transmitting infrared reflecting film (2) is formed on the inner surface of the bulb ω. Other identical parts are given the same reference numerals and explanations are omitted.0
In this example as well, the specific structure of the visible light transmitting infrared reflective film (2) and the tube end portion (2a) of this infrared reflective film (2) are moderately crystallized to have both infrared reflecting ability and visible light diffusing ability. Same as Example 1. The second embodiment is similar to the first embodiment described above. The desired illuminance range on the irradiated surface is wide, and the illuminance at the side edges of the irradiated surface is averaged, so there are no dark areas. Example 3 In this example, a light diffusing film is superimposed on the tube end portion of a visible light transmitting infrared reflective film, and the details are shown in Fig. 6. 0) is a straight tube bulb made of transparent quartz glass; is the visible light transmitting infrared reflective film formed on the outer surface of this bulb ■, ■
(2) is a light-diffusing film formed on the outer surface of the tube end portion of this infrared reflecting film (2); (2) is a sealing portion formed by crushing and sealing both ends of the bulb; (2); ■ is the molybdenum introduced foil embedded in these sealing parts) and (a), e and 0 are the inner conductors connected to these introduced foils ■ and ■ and placed inside the valve ω, and ■ is inside these Tungsten coil filament installed between conductor wires ■, ■
... is an anchor that supports this filament ■, a),
G11) is electrically connected to the introduction foils ■ and ■ to seal the sealing part H)
, @) is a terminal attached to the end face. Then, the required halogen is sealed inside the bulb ω together with an inert gas such as argon. As shown in Figure 6, the visible light transmitting and infrared reflecting film ■ is as follows:
The same high refractive index M (21) and low refractive index layer (
22) and 9 to 15 layers are alternately layered. The light-diffusing film (■) has air bubbles (32) in a transparent continuous film (31) made of metal oxides such as titanium oxide and tantalum oxide.
, (32)... If necessary, a plurality of such membranes (31) may be layered to improve the density of the bubbles. To obtain such a light-diffusing film (2), an appropriate amount of di-2-ethylhexyl phthalate (dioctyl phthalate, abbreviated as DOP) is added to an organometallic compound such as tetrapropyl titanate to form a visible light-transmissive, infrared-reflective film (2) on the tube end surface. The film is coated on the substrate and fired at a temperature of about 600° C. to form bubbles (32) formed by decomposing DOP in a transparent continuous film body (31) formed by decomposing the organometallic compound. This bubble (32) is III (
31) It consists of closed cells trapped inside and concave holes communicating with the outside, both of which have the property of diffusing visible light. Similar to the above-mentioned Example 1, in this example light bulb, infrared rays are reflected by the visible light-transmitting infrared reflecting film ■, and the filament ■
It is highly efficient because it returns to In addition, at the tube end of this light bulb, the visible light that has passed through the visible light transmitting infrared reflective MI■ is scattered by the diffuser film ■, so even though there is a low luminous intensity area at the tube end, the irradiated surface In this case, the illuminance is averaged, dark areas are eliminated, and the desired illuminance range is slightly wider. Further, there is an additional effect that the diffused light llI■ is difficult to peel off due to high temperature lighting. Example 4 In this example, in the structure shown in FIG.
As shown in the figure, a liquid made by dispersing light-diffusing powder (33) such as titanium oxide or zinc oxide 7 in an organic solvent together with a binder is applied to the surface of the visible light transmitting infrared reflective 1110 and then fired. are given the same reference numerals and the explanation will be omitted. This embodiment also has the same effects as the third embodiment described above. Modifications of Examples 3 and 4 In this modification, as shown in FIG. 8, a visible light transmitting and infrared reflecting film similar to that described above is formed on the inner surface of the bulb (1), and the film shown in FIG. 6 is formed on the outer surface of both ends of the bulb (1). Or similar diffused light as shown in Figure 7! ll■,■, and other 5th
Components that are the same as those shown in the figures are designated by the same reference numerals and descriptions thereof will be omitted. Also in this modification, the visible light that has passed through the °C infrared reflective film (2) at the tube end is scattered by the light scattering film (2), so for the same reason as described above, the effective illuminance range is wide and the illuminance distribution is uniform. As a modification of Examples 3 and 4, visible light transmitting and infrared reflecting films may be provided on both the inner and outer surfaces of the bulb, and in this case, a light scattering film may be provided on the outer surface of the infrared reflecting film. Further, in each of the above-described embodiments, one long filament is provided, but the present invention is not limited to this. For example, a plurality of filaments may be arranged in series and spaced apart, and the light-diffusing portion of the infrared reflective film and the light-diffusing film attached to the infrared reflective film may be provided at least at one end of the bulb, and then one Similar effects can be obtained by applying the invention to ordinary tube-shaped light bulbs. [Effects of the Invention] As described above, in the first tube-shaped light bulb of the present invention, at least one of the visible light transmitting and infrared reflecting films provided on at least one of the inner and outer surfaces of the tube-shaped light bulb has crystallization at the tube end. Because it has both infrared reflecting ability and visible light diffusing ability,
Since the infrared reflecting film reflects infrared rays and returns them to the filament to improve luminous efficiency and scatters visible light at the end of the tube, the desired illuminance range on the irradiated surface is wide and the illuminance distribution is uniform. Further, the tube-shaped light bulb of FIG. 2 of the present invention is provided with a visible light-transmissive infrared reflective film on at least one of the inner and outer surfaces of the tube-shaped light bulb, and a diffuser film is provided on the radiation side of the infrared reflective film at the end of the tube. Since they are provided in layers, the infrared rays are returned to the filament as in the first invention to improve the luminous efficiency, and the visible light that has passed through the infrared reflective film at the end of the tube is scattered to achieve the desired illuminance range on the irradiated surface. The area is wide and the illuminance distribution is uniform.

[Brief explanation of the drawing]

1rM is a sectional view of the first embodiment of the tube-shaped light bulb of the present invention;
Figure 2 is also a schematic enlarged sectional view of the main part, 3U5! J
4 is a sectional view of the second embodiment, FIG. 5 is a sectional view of the third embodiment, and FIG. 6 is a schematic enlarged sectional view of the main parts. FIG. 7 is a schematic enlarged sectional view of the main parts of the fourth embodiment, and FIG. 8 is a schematic enlarged sectional view of the main parts of the fourth embodiment.
This is a modification of the embodiment. ■...Bulb■...Visible light transmitting infrared reflective film (22)...High refractive index layer (22)...Low refractive index layer (2a)...Crystallized visible light transmitting infrared reflective film (21a)...Crystallized high refractive index layer ■...Scattered light g (31)...Transparent continuous film (32)
...Bubbles (33)...Diffusing powder■...
filament

Claims (2)

[Claims] (1) A visible light transmitting and infrared reflecting film is formed by alternately layering a high refractive index layer made of a metal compound and a low refractive index layer made of a different metal compound on at least one of the inner and outer surfaces of the tube-shaped light bulb. A tube-shaped light bulb, characterized in that at least one of the infrared reflecting films exhibits light-diffusing properties due to crystallization of at least one of the metal compounds at the end of the bulb. (2) A visible light transmitting infrared reflecting film formed by alternately layering a high refractive index layer and a low refractive index layer on at least one of the inner and outer surfaces of the tube-shaped light bulb, the end of the bulb A tube-shaped light bulb characterized in that a light-diffusing film is superimposed on the radiation side of the infrared reflecting film.