JP2011098852A - Envelope for flash lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an envelope for a flash lamp without causing the deterioration of a front lens and the reduction of the light quantity of the lamp even if the flash lamp has a small size. <P>SOLUTION: The flash lamp is configured to include glass containing, by mass, 45-80% SiO<SB>2</SB>, 11-22% B<SB>2</SB>O<SB>3</SB>, 0-15% Al<SB>2</SB>O<SB>3</SB>, 9-25% Cs<SB>2</SB>O, 0.001-0.1% Fe<SB>2</SB>O<SB>3</SB>and 0-2% TiO<SB>2</SB>. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an outer casing of a flash lamp, and more particularly to an outer casing of a small flash lamp.

  A strobe device mounted on a digital camera, a mobile phone, or the like has a flash lamp and a front lens made of transparent resin, and condenses the flash emitted from the flash lamp with the front lens and projects it onto a subject. The flash lamp used is an electronic flash lamp that generates flash by discharging a high voltage from an electrode in a tube filled with high-pressure xenon gas or the like. This kind of flash lamp has a very short lighting time of about 1/1000 second. In this short time intense light is emitted with heat.

  By the way, with the recent trend of miniaturization of devices, flash lamps have also been miniaturized, and thin and thin tube glass has been adopted for the lamp envelope.

Japanese Patent Application Laid-Open No. 2004-531445 JP 2006-306721 A JP-A-7-89743

    As a result of the miniaturization of equipment, problems that have not been a problem in the past have been recognized. More specifically, the flash lamp and the front lens have become closer to each other due to the miniaturization of the strobe device, and the influence of ultraviolet rays and heat rays leaking from the lamp on the lens has increased. In other words, the intensity of ultraviolet rays and heat rays per unit area irradiated on the lens is relatively large. As a result, the lens deteriorates rapidly and turns yellow, and the luminous flux from the lamp decreases, the color tone changes, and the appearance deteriorates.

Under such circumstances, it has been proposed to add an ultraviolet absorbing component to the jacket glass. For example, Patent Documents 1 and ₂ disclose flash lamp glass in which ultraviolet leakage outside the lamp tube is suppressed by adding Fe ₂ O ₃ or the like to the glass component.
However, it has been found that when a small flash lamp is manufactured using glass to which an ultraviolet absorbing component is added, another problem of easily causing a decrease in the lamp light amount occurs.

  An object of the present invention is to provide an outer envelope for a flash lamp that does not deteriorate the front lens and does not cause a reduction in the amount of light of the lamp even if it is a small flash lamp.

    As a result of various studies, the present inventors have found that the cause of the decrease in the light amount of the lamp is a synergistic effect of downsizing the outer casing glass and imparting an ultraviolet absorbing ability. That is, the surface area of the inner surface of the container is reduced by downsizing the lamp. On the other hand, the amount of ultraviolet rays generated in the lamp tube does not change greatly even if the lamp is downsized. That is, the ultraviolet irradiation amount per unit area on the inner surface of the container is significantly increased. Moreover, since the glass contains an ultraviolet absorbing component and absorbs the irradiated ultraviolet rays, excessive ultraviolet rays are absorbed by the glass. The absorbed strong ultraviolet energy cuts the weakly bonded portions of the glass structure, causing rearrangement of the glass structure and causing the glass near the inner surface to shrink. For this reason, strong tension arises between the deep glass which has not deteriorated, and a crack is generated on the inner surface of the container. The cracks generated on the inner surface diffusely reflect light and reduce the amount of light extracted from the lamp.

Furthermore, the present inventors have found that by adding Cs ₂ O having a large ionic radius to the glass, the shrinkage of the glass can be suppressed and the occurrence of cracks can be prevented.

Patent Document 3 discloses that by adding Cs ₂ O to glass for a flash lamp, coloring of the outer casing by the evaporated electrode material can be prevented, and the life of the flash lamp can be extended. However, Patent Document 3 neither describes nor suggests various problems associated with the miniaturization of flash lamps and the crack prevention effect of Cs ₂ O.

Envelope flash lamp of the present invention, _SiO 2 45 to _80% in mass _{percentage, B 2 O 3 11~22%,} Al 2 O 3 0~15%, Cs 2 O 9~25%, Fe 2 O 3 It is characterized by being made of glass containing 0.001 to 0.1% and TiO ₂ 0 to 2%.

In the present invention, the glass is further _{CeO 2,} WO 3, _ZnS, preferably contains from 0.001 to 1% in total of one or more selected from MoO _3, V 2 _{O 5.}

  According to the said structure, the ultraviolet-ray absorption performance of glass increases further and the effect which suppresses deterioration of resin peripheral members, such as a front lens, becomes large.

In the present invention, the glass is further in percentage by mass of Li ₂ O 0-5%, Na ₂ O 0-5%, K ₂ O 0-5%, MgO 0-10%, CaO 0-10%, SrO 0-. It is preferable to contain 10%, BaO 0 to 10%, and ZnO 0 to 10%.

  In the present invention, the container is preferably made of a tube glass having an outer diameter of 2 mm or less.

  According to the above configuration, it is necessary to increase the ultraviolet absorption performance to prevent the deterioration of the resin peripheral member, and accordingly, the glass is likely to be cracked. Therefore, the merit of applying the present invention is great. .

  In the present invention, the thickness of the container is preferably 0.5 mm or less.

  According to the above configuration, it is necessary to increase the ultraviolet absorption performance to prevent the deterioration of the resin peripheral member, and accordingly, the glass is likely to be cracked. Therefore, the merit of applying the present invention is great. .

  If the outer casing for the flash lamp of the present invention is used, even if it is a small strobe device in which the front lens and the flash lamp are installed close together, the front lens is hardly deteriorated because there is little ultraviolet light leaking outside the lamp tube. . In addition, although the amount of ultraviolet rays absorbed per unit area is large, the occurrence of cracks on the inner surface of the container can be effectively suppressed, so that it is difficult to cause a reduction in the light amount of the lamp.

The outer casing for the flash lamp of the present invention is made of SiO ₂ —B ₂ O ₃ glass containing Cs ₂ O and Fe ₂ O ₃ . The reason for limiting the glass composition as described above will be described below. In the following description, “%” means “mass%” unless otherwise specified.

SiO ₂ is a main component of glass, and its content is 45% or more, preferably 50% or more, and 80% or less, preferably 75% or less. If the content of SiO ₂ is 45% or more, it is possible to adapt the thermal expansion coefficient even if the electrode material is tungsten with low expansion. If it is 50% or more, high reliability in the market with respect to weather resistance can be obtained. On the other hand, if SiO ₂ is 80% or less, the glass is easily melted industrially, and if it is 75% or less, SiO ₂ -based crystals are likely to precipitate, which is preferable.

B ₂ O ₃ is a component that improves the weather resistance as well as the effect of lowering the thermal expansion coefficient of the glass. It is. If B ₂ O ₃ is 11% or more, the above effect can be obtained. On the other hand, if B ₂ O ₃ is 22% or less, the melting property of the glass is hardly deteriorated, and if it is 19% or less, it is difficult to volatilize even if the glass is reheated, which is advantageous when performing heat processing.

Al ₂ O ₃ has the effect of increasing the weather resistance of the glass and suppressing phase separation. However, it has the effect of increasing the high temperature viscosity. Al ₂ O ₃ is not an essential component but is preferably contained in an amount of 0.1% or more, particularly 1% or more, and more preferably 2% or more. If Al ₂ O ₃ is contained in an amount of 1% or more, phase separation is effectively suppressed to make it difficult to precipitate crystals, and if it is 2% or more, it is easy to stably perform thermal processing. On the other hand, if Al ₂ O ₃ is 15% or less, the risk that feldspar crystals precipitate on the glass can be reduced, and if it is 6% or less, the glass is easily melted.

Cs ₂ O is a component that has a large ionic radius and suppresses shrinkage of the glass to prevent the occurrence of cracks on the inner surface, and its content is 9% or more, preferably 12% or more, more preferably 10% or more, Moreover, it is 25% or less, Preferably it is 20% or less, More preferably, it is 17% or less. If the amount of Cs ₂ O is too small, the above effect cannot be obtained. Therefore, if sufficient ultraviolet absorptivity is to be obtained, cracks are generated on the inner surface of the container and the light quantity of the lamp is reduced. On the other hand, if it is too much, crystals will form in the glass.

Fe ₂ O ₃ is a component that imparts ultraviolet absorptivity to glass and prevents leakage of ultraviolet rays to the outside of the lamp tube, and its content is 0.001% or more, preferably 0.01% or more, more preferably 0. 0.02% or more, optimally 0.03% or more. If the amount of Fe ₂ O ₃ is too small, the above-mentioned effect cannot be obtained, so that a resin-made peripheral member such as a front lens deteriorates in a small strobe device. On the other hand, since Fe ₂ O ₃ causes the coloring of the glass, the content is preferably 0.1% or less, particularly 0.05% or less. The ultraviolet absorbent Fe ₂ O ₃ is changed by the redox of the glass. From the viewpoint of increasing the ultraviolet absorptivity, it is preferable to adjust the glass to the oxidation side. More specifically, it is desirable to control the Fe ²⁺ / total Fe amount to 0.7 or less.

TiO ₂ is a component having excellent ultraviolet absorption characteristics. On the other hand, when it coexists with Fe ₂ O ₃ or CeO _2, it tends to cause coloring. The crack of the inner surface and the TiO ₂ is too large tends to occur. TiO ₂ is an optional component, but when introduced into glass, it is preferably 0.001% or more, 0.01% or more, 0.02% or more, and most preferably 0.03% or more. Further, the upper limit is 2% or less, preferably 1% or less, more preferably 0.1% or less, and 0.03% or less is desirable for severely suppressing coloring.

The glass in the present invention preferably further contains at least one selected from CeO ₂ , WO ₃ , ZnS, MoO ₃ and V ₂ O ₅ as an ultraviolet absorbing component. When these components are contained, the total amount is 0.001% or more, preferably 0.01% or more, more preferably 0.02% or more, optimally 0.03% or more, and 5% or less. Preferably it is 3% or less, More preferably, it is 1% or less. If the total amount of these components is too small, there will be no effect of improving ultraviolet absorption. On the other hand, if the total amount of these components is too large, ultraviolet rays are absorbed too much, and even if a large amount of Cs ₂ O is added, generation of cracks cannot be suppressed. Moreover, it becomes easy to color glass.

CeO _{2 is} also a component having excellent ultraviolet absorption characteristics. When CeO ₂ is introduced, it is 0.001% or more, preferably 0.01% or more, particularly 1% or less. Crack the inner surface is likely to occur and CeO ₂ is too large.

When WO ₃ is introduced, its content is 0.001% or more, preferably 0.01% or more, and 5% or less, preferably 1% or less. If the amount of WO ₃ is too large, phase separation tends to occur, which is not preferable.

  ZnS is a component having excellent ultraviolet absorption characteristics. When ZnS is introduced, it is 0.001% or more, preferably 0.01% or more, and 1% or less, preferably 0.5% or less. If there is too much ZnS, phase separation tends to occur, which is not preferable.

When V ₂ O ₅ is introduced, its content is 0.001% or more, preferably 0.01% or more, and 1% or less, preferably 0.5% or less. Crack the inner surface is likely to occur and V ₂ O ₅ is too large.

When MoO ₃ is introduced, its content is 0.001% or more, preferably 0.01% or more, and 2% or less, preferably 0.5% or less. MoO ₃ is too large, the phase separation easily made by undesirable.

The glass in the present invention can further contain Li ₂ O, Na ₂ O, K ₂ O, MgO, CaO, SrO, BaO, ZnO and the like for various purposes.

Li ₂ O, Na ₂ O, and K ₂ O are components that have an effect of cutting the glass network, and are added to improve the meltability of the glass and adjust the thermal expansion coefficient. In the present invention, since it contains 9% or more of Cs ₂ O which is a kind of alkali metal oxide, when it is not necessary to increase the thermal expansion coefficient (for example, when sealing tungsten), these components are contained. It does not have to be. However, from the viewpoint of improving the initial solubility, it is preferable to contain Li ₂ O, Na ₂ O, and K ₂ O in a total amount of 0.1% or more. The total amount of these components is preferably 7% or less, particularly preferably 6% or less.

Li ₂ O has an effect of lowering the high temperature viscosity, and if it contains 2% or more of Al ₂ O ₃ and the high temperature viscosity tends to be high, it is preferable to contain 0.1% or more. The upper limit of Li ₂ O is 5%, preferably 3% or less.

The content of Na ₂ O is 0 to 5%, preferably 0 to 3%. Na ₂ O is too large, the weather resistance is impaired.

The content of K ₂ O is 0 to 5%, preferably 0 to 4%. K 2 _O is too large, the weather resistance is impaired.

  MgO and CaO are components that help melt the glass and increase the weather resistance, and their content is preferably 0 to 10%, particularly preferably 0 to 5%. When MgO or CaO exceeds 10%, the crystal tendency increases.

  SrO and BaO are components that lower the melting point of the glass and suppress the phase separation to stabilize the glass, and their contents are each preferably 0 to 10%, particularly preferably 0 to 5%. When SrO or BaO exceeds 10%, the crystal tendency becomes large.

  ZnO is a component that helps the glass melt and suppresses phase separation to stabilize the glass, and its content is preferably 0 to 10%, particularly preferably 0 to 5%. If ZnO exceeds 10%, the phase separation tendency increases and it becomes difficult to obtain glass with excellent dimensional accuracy.

Sb ₂ O ₃ is a component having an effect of reducing the coloring of Fe ₂ O ₃ . However, since it promotes internal cracks, its content is preferably 0 to 0.5%, particularly 0 to 0.1%, and more preferably 0 to 0.01%.

As ₂ O _{3 is} also a component having an effect of reducing the coloring of Fe ₂ O ₃ . However, the content is preferably 0 to 0.1%, particularly preferably 0 to 0.01% because it promotes internal cracks and is an environmentally undesirable substance.

  Cl is a component that can be effectively used as a fining agent. It is preferable to add 1% or less of Cl as a chloride to the raw material. The residual amount on the glass is about 0.01 to 0.3%.

SO ₃ is a component that provides a high clarification effect when used in combination with other clarifiers. It is preferable to add 0.003 to 0.5% of SO _{3 as} a sulfate to the raw material. Note that the remaining amount on the glass is about 0.0003 to 0.1%.

  The flash lamp envelope of the present invention is a tube glass having an outer diameter of 2 mm or less, particularly 1.1 to 1.8 mm, and a container thickness of 0.5 mm or less, particularly 0.25 to 0.5 mm. Is preferred. Along with the miniaturization of the lamp, the outer container is also required to be thinner and thinner. If the outer diameter and the wall thickness of the container are within the above ranges, it is possible to satisfy the demand for miniaturization of the lamp. The length of the outer container is not particularly limited, but is preferably about 5 to 7 mm, for example.

  Next, the flash lamp envelope of the present invention will be described.

  First, a glass raw material is prepared so as to obtain a glass having a desired composition, and a batch is produced. The batch is then melted at 1500-1650 ° C. and vitrified. In melting, glass may be clarified using a clarifier, but reduction clarification may be performed by adding carbon, metal aluminum powder, or the like to the batch. Subsequently, the molten glass is formed into a tubular shape using a downdraw method, a Dunner method, or the like, and cut into a predetermined length. In this way, the flash lamp envelope of the present invention can be obtained.

  Hereinafter, the present invention will be described using examples. Tables 1 and 2 show Examples (Sample Nos. 1 to 9) and Comparative Examples (Sample Nos. 10 to 12) of the present invention.

  First, glass raw materials were prepared so as to have the compositions shown in Tables 1 and 2, and batches were prepared. Silica powder, boric acid, alumina, sodium carbonate, cesium carbonate, magnesium oxide, calcium carbonate, salt, ferric oxide, titanium oxide, tungsten oxide, cerium oxide, zinc sulfide, vanadium pentoxide, arsenic trioxide Antimony oxide was used. In addition, the kind of raw material is not restricted to these, What is necessary is just to select suitably in consideration of the oxidation reduction state of glass, moisture content, etc. Moreover, content shown by a composition is a converted value, and is not limited to the title oxide valence.

  Next, the prepared batch was put into a melting furnace and melted at 1500 to 1650 ° C., and the tube was drawn by a down draw method. Thus, a tubular mantle container sample having a size of an outer diameter of 2.0 mm, a wall thickness of 0.3 mm, and a length of 20 mm was obtained, and the resin deterioration preventing property and crack preventing property were evaluated.

  Further, a batch was prepared in the same manner as described above, put into a platinum crucible, and melted at 1580 ° C. for 8 hours. Next, the glass melt was formed into a predetermined shape, and further subjected to necessary processing, and then the thermal expansion coefficient and ultraviolet absorption were evaluated. The results are shown in Tables 1 and 2.

As is apparent from Tables 1 and 2, sample No. which is an example of the present invention. Nos. 1 to 8 were excellent in ultraviolet absorptivity and excellent in resin deterioration prevention properties. Furthermore, since it contains Cs ₂ O, it is possible to produce a lamp that has good crack prevention properties and does not reduce the amount of light. No. 9 is sample No. Although it is slightly inferior in ultraviolet absorptivity as compared with 1 to 8, it has excellent anti-cracking properties and can be used sufficiently when combined with a resin with good UV resistance.

  In addition, a thermal expansion coefficient was measured with the thermal expansion measuring apparatus, and showed the average value of 30-380 degreeC.

  The ultraviolet absorptivity was evaluated as follows. First, a plate-like sample having a thickness of 0.4 mm whose both surfaces were optically polished was prepared, and the transmittance at a wavelength of 260 nm was measured with a transmittance measuring device (manufactured by Shimadzu Corporation). Samples having a transmittance of 20% or less at this wavelength were indicated by “◎”, samples exceeding 20%, “◯” indicating samples of 50% or less, and “x” indicating samples exceeding 50%.

  Resin deterioration prevention and crack prevention were evaluated as follows. First, an electronic flash lamp produced using an outer container sample (outer diameter 2.0 mm, wall thickness 0.3 mm, length 20 mm) was prepared. This flash lamp was set in a reflective case, and an acrylic plate was installed so that the distance from the flash lamp was 2 mm. Next, after the flash lamp was made to emit light 5000 times at 14 Ws, changes in the acrylic plate and the flash lamp mantle tube were observed. For the acrylic plate, “も の” indicates that no change was observed, “◯” indicates that the color was slightly changed to yellow, and “×” indicates that a strong color change was observed. For the outer container, “◎” indicates that no change was observed, “◯” indicates that some cracks were observed, and “×” indicates deterioration that caused internal peeling.

  The outer casing for a flash lamp of the present invention is suitable as an outer casing used for manufacturing a flash lamp, particularly a small flash lamp.

Claims (5)

_SiO 2 45 to _80% in mass _{percentage, B 2 O 3 11~22%,} Al 2 O 3 0~15%, Cs 2 O 9~25%, Fe 2 O 3 0.001~0.1, TiO 2 An outer casing for a flash lamp, characterized by comprising glass containing 0 to 2%. _2. The flash lamp according to claim 1, wherein the glass further contains 0.001 to 1% in total of at least one selected from CeO ₂ , WO ₃ , ZnS, MoO ₃ , and V ₂ O ₅ . A mantle container. Glass further by mass percentage _{Li 2 O 0~5%, Na 2} O 0~5%, K 2 O 0~5%, 0~10% MgO, CaO 0~10%, SrO 0~10%, BaO 0 The outer cover container for flash lamps according to claim 1 or 2, characterized by containing 10 to 10% and 0 to 10% of ZnO.   The outer casing of the flash lamp according to any one of claims 1 to 3, wherein the outer diameter of the container is made of a tube glass having a diameter of 2 mm or less.   The envelope for a flash lamp according to any one of claims 1 to 4, wherein the thickness of the container is 0.5 mm or less.