JP2001266800A - External electrode fluorescent lamp, and hot forming method for glass plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an external electrode fluorescent lamp, capable of freely setting light distribution in the direction of a cross section. SOLUTION: A plate glass substrate 2 and a molded glass substrate 3, molded into approximately U-shape are subjected to laser welding, to form a sealed container 10. One molded glass substrate 3 is provided with a light emission portion 5, which has a thickness t1 at the center, with a thickness which is 0.3-0.6 mm greater than a thickness t2 at both ends.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external electrode fluorescent lamp used in a document reading apparatus provided in an office automation apparatus such as a scanner or a copying machine, and a method for heat-forming a glass plate.

[0002]

2. Description of the Related Art An external electrode fluorescent lamp is used as a light source for reading a document in a document reading device provided in an OA device such as a scanner or a copying machine. As a conventional external electrode fluorescent lamp, for example, as described in JP-A-11-329366, a phosphor coating is formed on the inner surface of a glass tube having a circular cross section except for an aperture for emitting light. It is known that a pair of band-shaped electrodes is provided on the outer surface of a glass tube symmetrically with respect to the tube axis with an aperture portion interposed therebetween, and the outer periphery thereof is covered with an insulating transparent resin.

Here, if the width of the strip-shaped electrode is increased, the amount of electric charge to be stored is increased, so that the lamp generates a large amount of light. However, if the width is too large, the length of the outer periphery of the glass tube is determined, so that the aperture becomes large. Since the angle becomes narrow, the amount of light inside cannot be effectively emitted to the outside. Further, if the distance between the electrodes on the back side facing the aperture portion is too small, dielectric breakdown may occur under high-temperature and high-humidity use conditions, which is not preferable. Therefore, the width of the strip-shaped electrode, the aperture angle, and the distance between the electrodes (the aperture portion and the back surface portion) are set to appropriate values.

[0004]

However, since the aperture angle is generally restricted within the range of 60 ° to 90 °, the light distribution cannot be set on the lamp side. When the aperture angle is less than 60 °, the light beam cannot be emitted effectively,
If the angle is more than °, the electrode width becomes too narrow and electric power cannot be effectively supplied to the entire inside of the tube. In addition, since the cross section of the aperture portion is arc-shaped, the light beam emitted from the aperture portion is substantially uniformly diffused, and thus has no directivity, so that the light distribution cannot be set on the lamp side.

The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide an external electrode fluorescent lamp and glass capable of arbitrarily setting a light distribution in a sectional direction. An object of the present invention is to provide a method for heat forming a plate.

[0006]

According to a first aspect of the present invention, there is provided a closed container formed by bonding two glass members, at least one of which is a molded glass substrate.
The light emitting portion is provided on the one molded glass substrate.

According to a second aspect of the present invention, in the external electrode fluorescent lamp according to the first aspect, the light emitting portion is formed such that a thickness at a center thereof is 0.3 mm to 0.6 mm thicker than a thickness at an end portion. It was formed.

According to a third aspect of the present invention, in the external electrode fluorescent lamp according to the first or second aspect, the two glass members are bonded by laser fusion.

The invention according to claim 4 uses a forming method in which a glass plate is pressed with a convex upper mold and a concave lower mold while heating at a temperature higher than the softening point, and the molded glass plate is pressed into the concave lower mold. A concave portion is provided so that the protruding portion does not come into contact, the viscosity of the glass is maintained in a range of 10,000 poise to 20,000 poise for a predetermined time after press molding, and a different thickness portion is formed on the protruding portion of the glass plate using viscous flow. Is formed.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a sectional view of the external electrode fluorescent lamp according to the present invention, FIG. 2 is a configuration diagram of an illumination system of a document reading apparatus using the external electrode fluorescent lamp according to the present invention, and FIG. 3 is another embodiment of the present invention. FIG. 4 is a cross-sectional view of an external electrode fluorescent lamp according to an embodiment of the present invention, FIG. 4 is a configuration diagram of an illumination system of a document reading apparatus using an external electrode fluorescent lamp according to another embodiment of the present invention, and FIG. FIG. 6 is a cross-sectional view of the external electrode fluorescent lamp of FIG.

As shown in FIG. 1, an external electrode fluorescent lamp 1 according to the present invention forms a tubular member 4 by fusing a plate glass substrate 2 and a molded glass substrate 3 with a laser. A phosphor coating 6 is formed on the inner surface except for a light emitting portion 5 that emits light, and the molded glass substrate 3 is sandwiched between the light emitting portions 5.
A pair of strip-shaped electrodes 7 and 8 are provided on the outer surface in a tube axis symmetrical manner, and the entire outer periphery thereof is covered with an insulating light-transmitting resin film 9. In addition, side members (not shown) forming the closed container 10 together with the tubular member 4 are fused to both ends of the tubular member 4 by laser.

The molded glass substrate 3 is formed in a substantially U-shape, and a light emitting portion 5 is provided at a central portion thereof. The light emitting portion 5 has an inner surface formed by a curved surface having a radius of curvature (r1) of 4.3 mm and an outer surface formed by a curved surface having a radius of curvature (r2) of 3.0 mm. Than,
0.3 mm to 0.6 mm thick (0.3 mm ≦ t
1−t2 ≦ 0.6 mm), and functions as a convex lens. Also,
The aperture angle θ of the light emitting section 5 is 90 °.

Here, as the thickness difference (t1−t2) between the center thickness t1 and the end thickness t2 increases, the light condensing effect increases. However, when the thickness difference (t1−t2) exceeds 0.6 mm, the directivity appears on the light beam.
When -t2) is less than 0.3 mm, the effect of the thickness difference is not obtained. Therefore, the range of 0.3 mm ≦ t1−t2 ≦ 0.6 mm is effective for improving the diffusion. It is preferable that the light emitting portion 5 is transparent to prevent unnecessary diffusion.

The width of each of the strip electrodes 7 and 8 is
Can be set arbitrarily without being restricted by the radii of curvature r1 and r2 of the inner and outer surfaces of. However, if the width of the strip electrodes 7 and 8 is too large and the distance between the strip electrodes 7 and 8 becomes small,
It is necessary to consider dielectric breakdown under high temperature and high humidity.

In the external electrode fluorescent lamp 1 according to the present invention, the inner and outer diameters (radius of curvature r1, r2) of the light emitting portion 5 can be finely adjusted, and the inner and outer diameters (curvature radii r1, r2) can be arbitrarily set. Can be set. Also, for example, even when a high-power lamp is used for the illumination system of the document reading apparatus, the inner and outer diameters (curvature radii r1, Adjustment of r2) is possible.

A sheet glass substrate 2 and a molded glass substrate 3
The sealing of the sealed portion of the hermetically sealed container 10 composed of the side member (not shown) and the side member (not shown) was performed by a laser fusion method. In the method, first, the entire closed container 10 is kept at a temperature of the softening point, and then the sealing portion between the sheet glass substrate 2 and the molded glass substrate 3 and the sealing portion between the tubular member 4 and the side member (not shown) are This is a method in which each is heated to about 1000 ° C. by a carbon dioxide laser and fused.

Conventionally, sealing between glass substrates has been performed by bonding with low melting point glass. For example, low melting glass LS-0118 manufactured by Nippon Electric Glass Co., Ltd. was liquefied with a solvent such as tarpinol, applied to a sealing portion, and bonded by baking at 450 ° C. in air. However, since low-melting glass contains lead, lead-free is being studied recently as a measure to reduce substances of concern. Thus, in the present invention, the above-described fusion method using a laser is employed as a measure against lead-free.

[0018] By adopting the fusion method using a laser, as an effect other than lead-free, a slow leak phenomenon in which micro peeling occurs at the interface between the low-melting glass and the glass substrate has been a concern in the past. In the case of fusion, there was no such phenomenon.

The external electrode fluorescent lamp 1 thus configured has, for example, a width w of 19.0 mm and a height h of 9.5 mm.
A pair of strip-shaped electrodes 7, 8 and a phosphor coating 6 generate light in a sealed container 10, and the generated light is transmitted from a light emitting portion 5 serving as a convex lens to a desired light flux width. Out.

As shown in FIG. 2, the illumination system of the original reading apparatus using the external electrode fluorescent lamp 1 has an original surface glass 12 as an original table on which an original 11 is placed, and a lower surface of the original surface glass 12 as shown in FIG. An external electrode fluorescent lamp 1 and a reflecting mirror 13 for reflecting light emitted from the external electrode fluorescent lamp 1 are provided. Reference numeral 14 denotes a reflecting mirror for reflecting the contents of the document 11, and reference numeral 15 denotes a CCD image pickup device as an image pickup device.

The document reading apparatus reads the contents of the document 11 by moving the illumination system at a predetermined speed in a state where the document 11 is fixed to the document surface glass 12, and reads the contents of the document 11 in a state where the illumination system is fixed. 11 is a document surface glass 12 at a predetermined speed.
There is a method of reading the contents of the document 11 by moving it upward.

The light distribution P on the document surface has a width of 4 mm to 6 mm around the optical axis C. Digital scanners and copiers have a CCD light-receiving surface,
The reading width on the document surface is about 70 μm. Therefore, although the ideal light distribution is a line, the actual desired light distribution is actually varied due to variations in the position of the illumination system such as the lamp 1 and the reflecting mirror 13 and variations in reading of the CCD optical system. It is in the above range.

The radius of curvature (r) of the inner surface of the light emitting portion 5
1) 4.3 mm and the radius of curvature (r2) of the outer surface are 3 mm, the thickness t3 of the original glass 12 is 3 mm to 4 mm, and the distance d1 between the original glass 12 and the external electrode fluorescent lamp 1 is 2 m.
m, the distance d2 between the external electrode fluorescent lamp 1 and the optical axis C is 2 m
m, the light distribution P has a width of 4 mm to 6 around the optical axis C.
mm. The reason that the distance d1 between the original surface glass 12 and the external electrode fluorescent lamp 1 is set to 2 mm is to leave a space of 2 mm or more in consideration of the heat cracking of the original surface glass 12 due to the heat generated by the external electrode fluorescent lamp 1 and the bending of the glass. It is necessary.

Further, the reflecting mirror 13 for reflecting the light emitted from the external electrode fluorescent lamp 1 is not always necessary. This is because a desired light distribution P can be obtained by increasing the light condensing effect of the light emitting section 5 by the convex lens function.

FIG. 3 shows an external electrode fluorescent lamp 21 according to another embodiment of the present invention. This external electrode fluorescent lamp 21
Forms a tubular member 24 by fusing a plate glass substrate 22 and a formed glass substrate 23 with a laser, and forms a phosphor coating 26 on the inner surface of the tubular member 24 except for a light emitting portion 25 that emits light. A pair of strip-shaped electrodes 27 and 28 are provided on the outer surface of the molded glass substrate 23 symmetrically with respect to the tube axis with the light emitting portion 25 interposed therebetween.
9. In addition, a side member (not shown) that forms the sealed container 30 together with the tubular member 24 is fused to both ends of the tubular member 24 by laser.

The molded glass substrate 23 is formed into a substantially M-shaped concave surface, and a light emitting portion 25 is provided at the center thereof.
The light emitting section 25 has two light emitting surfaces 25a and 25b. Other configurations are almost the same as those of the external electrode fluorescent lamp 1 shown in FIG.

FIG. 4 shows an illumination system of a document reading apparatus using the external electrode fluorescent lamp 21. This illumination system includes a document surface glass 32 as a document table on which a document 31 is placed.
And an external electrode fluorescent lamp 21 disposed opposite to the lower surface of the original surface glass 32, a reflecting mirror 33 for reflecting the light emitted from the external electrode fluorescent lamp 21, and the like. Note that 34
Is a reflecting mirror for reflecting the contents of the document 31, 35 is a CCD image pickup device as an image pickup device, and 36 is an optical axis.

Light from one emission surface 25a of the light emission part 25 is reflected by the reflecting mirror 33 and proceeds to the original surface glass 32.
Light from the other exit surface 25b is directly transmitted to the original surface glass 32.
To form a light distribution P about the optical axis C on the original surface with the reflected light and the direct light. Therefore, the reflecting mirror 33 is an essential component for reflecting light from the emission surface 25a. The external electrode fluorescent lamp 21 has a feature that the emission surfaces 25a and 25b are farther from the original surface glass 32 but are not diffused as compared with the external electrode fluorescent lamp 1 shown in FIG.

FIG. 5 shows an external electrode fluorescent lamp 41 according to another embodiment of the present invention. The external electrode fluorescent lamp 41 forms a tubular member 44 by fusing a molded glass substrate 42 and a molded glass substrate 43 with a laser, and excludes a light emitting portion 45 that emits light to the inner surface of the tubular member 44. A phosphor film 46 is formed, a pair of strip-shaped electrodes 47 and 48 are provided on the outer surface of the molded glass substrate 43 symmetrically with respect to the tube axis with the light emitting portion 45 interposed therebetween, and the entire outer periphery thereof is coated with an insulating translucent resin film 49. Coated. In addition, side members (not shown) forming the closed container 50 together with the tubular member 44 are fused to both ends of the tubular member 44 by laser.

The formed glass substrate 42 is formed in an arc shape. The molded glass substrate 43 is formed in a substantially U-shape, and a light emitting portion 45 is provided at the center thereof. For other configurations, the external electrode fluorescent lamp 1 shown in FIG.
Is the same as

Next, the method of heat-forming a glass sheet according to the present invention will be described. The method of heat forming this glass sheet
As shown in FIG. 6, a glass plate 50 is compressed and molded by a convex upper mold 51 and a concave lower mold 52, and a molding method utilizing the fluidity of glass softened after press molding and its movement in the direction of gravity. is there.

In order to form a half of a tubular member,
The convex upper mold 51 is formed with a peak, and the concave lower mold 52 is formed with a valley matching the peak of the convex upper mold 51. Further, a space is formed in the concave lower mold 52 so that the projecting portion 53 of the formed glass plate 50 does not contact the concave lower mold 52 even when the convex upper mold 51 comes into contact with the concave lower mold 52. A recess 54 to be formed is provided.

In the heat forming method of the glass plate, first, as shown in FIG. 6A, the glass plate 50 is heated above the softening point in a state of being placed on the concave lower mold 52 as shown in FIG.

Next, as a second step, as shown in FIG. 6 (b), the convex plate 51 presses the glass plate 50 while heating it above the softening point.

Next, as a third step, as shown in FIG. 6C, the convex upper mold 51 is brought into contact with the concave lower mold 52 while heating to a temperature higher than the softening point. Then, even after press molding, a different thickness portion is gradually formed in the protruding portion 53 by its own weight.

In the fourth step, as shown in FIG. 6D, when the viscosity of the glass is maintained in the range of 10,000 poise to 20,000 poise for a predetermined time (several minutes), the flow of the softened glass is reduced. The molded glass substrate 55 in which a different thickness portion having a desired thickness difference (for example, 0.3 mm to 0.6 mm) is formed in the protruding portion 53 by the property and the movement in the gravity direction is manufactured.

Since the inner surface 53a and the outer surface 53b of the projection 53 do not come into contact with the convex upper mold 51 and the concave lower mold 52 during the molding process in the fourth step, the projection 53 is molded in a transparent state. The translucency of 53 is maintained. On the other hand, the inclined portion 56 where the convex upper mold 51 and the concave lower mold 52 come into contact is formed in an opaque state. Therefore, since the inner surface 53a and the outer surface 53b of the protruding portion 53 can be molded transparently, finishing work such as polishing after molding is not required, which contributes to a reduction in man-hours.

Further, when the glass viscosity becomes less than 30,000 poise, the fluidity becomes active and the glass starts to move in the direction of gravity. However, if the thickness is less than 8,000 poise, the movement is considerably large, so that a minute control with a thickness difference of 0.6 mm or less cannot be performed. As a result, the range of 10,000 poise to 20,000 poise (in terms of temperature, 1000 ° C. to 110
0 ° C, 950 ° C to 1030 for PPG Pure Site
C.) for a few minutes, a thickness difference of 0.3 mm to 0.6 mm is formed.

Since the speed at which the glass moves in the direction of gravity differs depending on the magnitude of the inclination angle α of the formed glass substrate 25, the holding time for keeping the viscosity in the range of 10,000 poise to 20,000 poise is determined by the inclination angle α. It takes about 2 minutes at 60 ° and about 9 minutes at 45 °.

In addition, there is a difference in the holding time for maintaining the viscosity in the range of 10,000 poise to 20,000 poise even in the size of the formed glass substrate 25 to be manufactured. When the inclination angle α is 45 °, A4
It takes about 6 minutes for the size and about 9 minutes for the A3 size.

The thickness of the center of the protruding portion 53 is larger than the thickness of the end portion by 0.1 mm by the method of hot-forming a glass sheet according to the present invention.
The molded glass substrate 3 used for the external electrode fluorescent lamp 1 shown in FIG. 1 and the molded glass substrate 42 used for the external electrode fluorescent lamp 41 shown in FIG. can do.

In the embodiment of the glass sheet heat forming method according to the present invention, as shown in FIG.
As the molded glass substrate 55 to be molded, a half of a tubular member such as the molded glass substrate 3 shown in FIG. 1 has been described. However, according to this method of heating and molding a glass plate, by changing the shapes of the convex upper mold 51 and the concave lower mold 52, even a half of a spherical member such as a head of a light bulb has a different thickness in the protruding portion. And can be molded.

[0043]

As described above, according to the first aspect of the present invention, the shape of the light exit surface can be arbitrarily determined, and the light distribution can be set on the lamp side.

According to the second aspect of the present invention, since the convex lens is formed at the light emitting portion, the light condensing characteristics are improved, a desired light distribution can be obtained, and the illumination system of the document reading apparatus can be used. When applied, it is possible to omit a reflecting mirror for transmitting light to the original surface glass.

According to the third aspect of the present invention, since the glass itself is heat-sealed, there is no occurrence of micro-peeling and there is no slow leak phenomenon.

According to the fourth aspect of the present invention, since the inner surface and the outer surface of the projecting portion do not come into contact with the upper and lower molds during the molding process, they are molded in a transparent state and are transparent. Light properties are maintained. Further, since the inner surface and the outer surface of the protruding portion can be formed transparently, finishing work such as polishing after forming is not required, which contributes to reduction in the number of steps.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an external electrode fluorescent lamp according to the present invention.

FIG. 2 is a configuration diagram of an illumination system of a document reading apparatus using an external electrode fluorescent lamp according to the present invention.

FIG. 3 is a sectional view of an external electrode fluorescent lamp according to another embodiment of the present invention.

FIG. 4 is a configuration diagram of an illumination system of a document reading apparatus using an external electrode fluorescent lamp according to another embodiment of the present invention.

FIG. 5 is a sectional view of an external electrode fluorescent lamp according to another embodiment of the present invention.

FIG. 6 is an explanatory view of a method for heat-forming a glass sheet according to the present invention.

[Explanation of symbols]

1,21,41 ... external electrode fluorescent lamp, 2,22 ... plate glass substrate, 3,23,42,43 ... molded glass substrate,
4, 24, 44 ... tubular member, 5, 25, 45 ... light emitting portion, 6, 26, 46 ... phosphor coating, 7, 8, 27,
28, 47, 48: band-shaped electrode, 9, 29, 49: translucent resin film, 10, 30, 50: sealed container, 50: glass plate, 51: convex upper type, 52: concave lower type, 53: projection Department,
54 ... recess.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C012 EE02 EE08 5C043 AA02 AA04 AA14 BB03 CC09 CC16 CD01 CD13 DD01 EA01 EB15 EC02

Claims (4)

[Claims] 1. An external electrode fluorescent lamp comprising two glass members, at least one of which is a molded glass substrate, bonded together to form a sealed container, and said one of the molded glass substrates is provided with a light emitting portion. 2. The external electrode fluorescent lamp according to claim 1, wherein the light emitting portion is formed such that a thickness at a center thereof is 0.3 mm to 0.6 mm thicker than a thickness at an end portion. 3. The external electrode fluorescent lamp according to claim 1, wherein said two glass members are bonded by laser fusion. 4. A molding method in which a glass plate is pressed with a convex upper mold and a concave lower mold while being heated to a temperature higher than a softening point, and a projected portion of the formed glass plate is not brought into contact with the concave lower mold. A concave portion is provided, and after the press molding, the viscosity of the glass is maintained in a range of 10,000 poise to 20,000 poise for a predetermined time, and a different thickness portion is formed on the protruding portion of the glass plate using viscous flow. Heat forming method for a glass plate.