JPH0479149A - Fluorescent lamp - 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 [Object of the Invention] (Industrial Application Field) The present invention relates to a fluorescent lamp that is effective for use as a light source for office automation equipment such as OCR, image scanner, and facsimile machines.

(Prior art) OA equipment such as OCR, image scanner, and facsimile machines use fluorescent lamps as light sources, illuminate a document with light emitted from the fluorescent lamp, and capture the image reflected by the document on a CCD. It is designed to be detected using a light-receiving element like a nato.

An example of this will be described with respect to an image scanner shown in FIG.

In the figure, 1 is a fluorescent lamp as a light source, 2 is a lamp housing with a reflective surface, 3 is an original table made of glass, etc., 4 is an original, 5.6 is a mirror 7 is an imaging lens, and 8 is a COD sensor. It is.

The light emitted from the fluorescent lamp 1 is transmitted to the lamp housing 2.
The light is reflected by the beam and illuminates the original 4 placed on the original placing table 3.

The image reflected by the original 4 is reflected by a mirror 5.6, passes through an imaging lens 7, and is imaged on a CCD sensor 8.

By the way, the silicon-based photoelectric sensor used in the CCD sensor 8 has spectral sensitivity in the near-infrared region around 800 to 11,000 nm.

Therefore, it senses wavelengths in the near-infrared region.

On the other hand, the fluorescent lamp 1 normally emits ultraviolet rays by emitting light from mercury vapor ions, but when used at low temperatures, mercury vapor is insufficient and a rare gas for starting is used. In some cases, the gas is filled with argon gas or discharged to emit light. Such argon light emission is in the infrared region.

Therefore, in the image scanner shown in FIG. 7, when the fluorescent lamp 1 emits argon light due to rare gas discharge, the CCD sensor 8 having spectral sensitivity in the near-infrared region senses this and malfunctions. In other words, the CCD sensor 8 may mistakenly detect something that is not a character or figure as a character or figure.

In order to prevent such problems, conventional structures have been adopted, such as providing an infrared cut filter 9 in front of the imaging lens 70 shown in FIG. 7, or coating the surface of the imaging lens 70 with an infrared cut film. .

If the second method is adopted, the infrared cut filter 9 and the infrared cut film formed on the surface of the imaging lens 7 block near infrared rays, so that malfunction of the CCD sensor 8 can be prevented.

(Problems to be Solved by the Invention) However, the above conventional structure uses a special infrared cut filter 9, which increases the number of parts, requires time and effort to assemble, and requires space for installing the infrared cut filter 9. There is a problem with the device becoming too large.

Furthermore, forming an infrared cut film on the surface of the imaging lens 7 requires an infrared cut film formation process in addition to the lens manufacturing process, and such infrared cut film forming technology has the disadvantage of increasing costs. be.

The present invention provides a fluorescent lamp that employs a structure that does not emit infrared rays in the lamp itself, and eliminates the need for an infrared cut filter or an infrared cut film on the surface of an imaging lens when used as a light source for OA equipment. That is.

[Configuration of the Invention (Means for Solving the Problems) The first aspect of the present invention is that the glass of the glass bulb contains a near-infrared blocking substance that prevents near-infrared rays from passing through. .

The second aspect of the present invention is that on the inner or outer surface of the glass bulb,
It is characterized by forming a near-infrared blocking layer that prevents near-infrared rays from passing through.

The third aspect of the present invention is characterized in that the outer surface of the glass bulb is coated with a film containing a near-infrared blocking substance that prevents near-infrared rays from passing through.

(Function) In the present invention, the near-infrared blocking substance blocks infrared rays that are about to be emitted from the lamp, regardless of whether it is the first to third substance, so that no infrared rays are emitted outside the lamp.

(Example) The first example of the present invention will be described below with reference to FIGS. 1 and 2.
This will be explained based on the diagram.

FIG. 1 shows a straight tube fluorescent lamp used as a light source for image scanners, etc., and 10 is a bulb made of soda lime glass.

Both ends of the bulb 10 are sealed with stems 11.11, and these stems 11.11 are fitted with filament electrodes 1.
2.12 is installed.

Caps 13.13 are attached to both sides of the bulb 10, and projecting cap pins 14 connected to the electrode unit 2.12 are provided on these caps 13.13.

A phosphor coating 15 is formed on the inner surface of the bulb 10, as shown in FIG. For example, a calcium halophosphate phosphor is used as the phosphor.

The inside of the valve 10 is filled with a predetermined amount of mercury and a starting rare gas such as argon.

In this embodiment, a near-infrared blocking material 16, that is, a near-infrared absorbing material 16, is provided inside the glass constituting the bulb 10.
Or it is mixed in.

Ionized transition metals are suitable as near-infrared absorbing substances, and transition metals have the property of absorbing near-infrared rays due to the transition of their d electrons, that is, the transition from a low energy state to a high energy state.

For example, V4+ is 1100rvSF e” is 1000ni
.

Cu'' exhibits relatively strong absorption at 800 nam.

Therefore, if the near-infrared absorbing material 16 made of the transition metal ions is made into fine powder, dispersed in soda lime glass, and the bulb 10 is formed using this glass,
A near-infrared absorbing bulb, ie a fluorescent lamp, is obtained.

If such a fluorescent lamp is used as the light source of the image scanner shown in Figure 6, even if the argon sealed as a starting rare gas discharges and emits infrared light in a low temperature state, the bulb will not be close to 1°. Because it blocks infrared rays,
Near-infrared radiation is prevented.

Therefore, near-infrared rays do not reach the CCD sensor 8, and malfunction can be prevented.

Further, since near-infrared rays attempting to emit from the bulb 10 are blocked, heating of surrounding members such as the housing 2 and the original table 3 is prevented.

Moreover, such a configuration eliminates the need for a special infrared cut filter 9, prevents an increase in the number of parts, requires no effort to assemble, and requires no installation space for the infrared cut filter '9, which reduces the size of the equipment. It is possible to prevent the formation of

Furthermore, since there is no need to form an infrared ray cut film on the surface of the imaging lens 7, the cost is reduced.

In the manufacturing process of fluorescent lamps, there is an additional step of dispersing the near-infrared absorbing material 16 made of transition metal ions into soda lime glass, but such a step does not interfere with the lamp manufacturing process and is an important part of the lamp manufacturing process. The effort is almost the same as before.

Next, a second embodiment will be described based on FIGS. 3 and 4.

The fluorescent lamp of this embodiment is an aperture type fluorescent lamp.

That is, 20 is a straight tube-shaped bulb made of soda lime glass, and a reflective film 21 and a phosphor film 22 are formed on the inner surface at a predetermined angle in the circumferential direction. Therefore, a band-shaped transparent portion 23 is formed along the axial direction of the bulb 20, where the reflective film 21 and the phosphor coating 22 are not formed, and this band-shaped transparent portion serves as a light-transmitting slit portion 23. . For this reason, this fluorescent lamp emits light only from the slit portion 23, and has a so-called directional aperture shape.

A stem 11, an electrode 12, and a base 1 are installed at both ends of the bulb 20.
3 is provided, which is similar to the first embodiment.

A near-infrared absorbing layer 25 is formed on the outer surface (or inner surface) of the bulb 20 so as to cover the slit portion 23 .

This near-infrared absorbing layer 25 is formed of a near-infrared absorbing material made of transition metal ions.

That is, for example, a near-infrared absorbing substance made of transition metal ions such as V44 Fe"(:u") is made into fine powder, dissolved in an organic solvent to create a suspension, and this suspension is applied to the outer surface of the valve 20. The organic solvent is applied so as to cover the slit portion 23. Thereafter, the bulb 20 is heated to scatter the organic solvent to form a near-infrared absorbing material layer 25 on the outer surface of the bulb 20.

Even in an aperture-type fluorescent lamp having such a configuration, the near-infrared rays of the light emitted from the slit portion 23 are absorbed by the near-infrared absorbing layer 25, so that they are prevented from being emitted to the outside, and the visible light is only will be released.

Therefore, in this case as well, malfunction of the CCD sensor 8 can be prevented, and surrounding members such as the housing 2 and the original table 3 can be prevented from being heated.

Note that the near-infrared absorbing layer 25 is not limited to being formed of a near-infrared absorbing substance made of transition metal ions as described above, and may be formed of a multilayer optical interference film as in the third embodiment shown in FIG. It may be composed of

That is, the near-infrared blocking layer may be constructed by forming a visible light-transmitting infrared reflecting film 30 on the outer surface of the bulb 20, as shown in FIG. This visible light transmitting infrared reflecting film 30 is configured as a multilayer film having, for example, a total of 9 to 17 layers, with high refractive index layers 31 and low refractive index layers 32 stacked alternately. The high refractive index layer 31 is made of titanium oxide (T102)% tantalum oxide (TA205), zirconium oxide (ZrO2)
, zinc sulfide (ZnS), etc., and the low refractive index layer 32 is made of silicon oxide (silica-3iO2), magnesium fluoride (MgF2), etc.

The visible light transmitting infrared reflecting film 30 made of such a multilayer film can transmit a desired wavelength by selecting the material, film thickness, and number of laminated layers, but can have a light interference effect that absorbs or reflects other wavelengths. Even if the visible light transmitting infrared reflecting film 30 is formed with such a light interference film,
For example, it is possible to reflect infrared rays of 800 to 1200 ns and transmit only visible light.

In the second and third embodiments, an aperture-type fluorescent lamp has been described, but the near-infrared absorbing layer 25 and the visible light-transmitting infrared-reflecting film 30 made of a multilayer laminated film can be applied to an aperture-type fluorescent lamp. However, it can also be applied to lamps that emit light in all directions.

Next, a fourth embodiment will be explained based on FIG. 6.

In this embodiment, a film 41 is attached to the outer surface of a bulb 40, and a near-infrared absorbing substance (not shown) is mixed into this film 41 and dispersed therein. The film 41 may be a transparent resin film, but in this embodiment, a heat-shrinkable resin film such as polyamide resin is used, and the polyamide resin is coated with the V"Fe2"
A near-infrared absorbing substance made of transition metal ions such as Cu'' is mixed into fine powder.

If the resin film 41 is heat-shrinkable, when it is placed over the bulb 40 and heated, it will adhere tightly to the outer surface of the bulb 40, so it can be coated easily without using an adhesive, and wrinkles are less likely to occur.

Even in a fluorescent lamp with such a configuration, the bulb 40
Of the light that is about to be emitted, the near-infrared rays are absorbed by the near-infrared absorbing material mixed in the film 41, so that they are blocked from being emitted to the outside, and only visible light is emitted.

When such a film 41 is used, it can also be applied to the aperture type fluorescent lamp described above.

Note that the present invention is not limited to the above embodiments.

That is, the fluorescent lamp is not limited to a straight tube shape, but may be a ring-shaped, U-shaped, W-shaped, or other fluorescent lamp.

The electrode is not limited to a hot cathode made of a filament, but may be a cold cathode.

Furthermore, the lamp is not limited to being used as a light source for office automation equipment such as an 0CR1 image scanner or facsimile, and may be used as a fluorescent lamp for general illumination.

[Effects of the Invention] As explained above, in any of the first to third aspects of the present invention, the near-infrared blocking material blocks the emission of near-infrared rays, so the lamp itself no longer emits infrared rays, making it easier for office automation equipment, etc. When used as a light source, there is no need for an infrared cut filter or an infrared cut film on the surface of the imaging lens, and even in normal use, heat emission is reduced so that surrounding members are not heated.

[Brief explanation of drawings]

1 and 2 show a first embodiment of the present invention, in which FIG. 1 is a perspective view of a straight tube fluorescent lamp, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 3 and 4 are the second embodiments of the present invention.
3 is a perspective view of an aperture type fluorescent lamp, FIG. 4 is a sectional view taken along the line IV-mV in FIG. 3, and FIG.
The figure is a cross-sectional view showing the structure of a visible light transmitting infrared reflective film showing a third embodiment of the present invention, FIG. 6 is a cross-sectional view of a fluorescent lamp showing a fourth embodiment of the present invention, and FIG. FIG. 1 is a configuration diagram of an image scanner shown to explain a conventional technique. DESCRIPTION OF SYMBOLS 10... Bulb, U2... Electrode, 15... Fluorescent coating, 16... Near-infrared absorption material, 20... Bulb, 21... Reflective film, 22... Fluorescent light body capsule, 2
B, -. Slit portion, 25...Near-infrared absorbing film, 30. . Visible light transmitting infrared reflective film, 40... Bulb, 41...
・Heat shrinkable film.

Claims (3)

[Claims] (1) A glass bulb having an electrode at the end and a phosphor coating formed on the inner surface contains a near-infrared blocking substance that blocks the transmission of near-infrared rays in the glass of the glass bulb. light lamp. (2) A fluorescent lamp characterized in that a near-infrared blocking layer is formed on the inner or outer surface of a glass bulb having an electrode at the end and a phosphor coating formed on the inner surface to prevent near-infrared rays from transmitting. lamp. (3) The outer surface of the glass bulb, which has an electrode at the end and a phosphor coating formed on the inner surface, is coated with a film containing a near-infrared blocking substance that prevents near-infrared rays from passing through. Fluorescent lamp.