JPH02309550A - Aperture type low pressure discharge lamp - Google Patents

Abstract

PURPOSE:To improve the bond strength of a shading member and prevent flickering of the irradiated light by irregularly forming a surface of a valve on which the shading member is to be provided. CONSTITUTION:All of the surface of a valve 2 of a low pressure discharge lamp, in which inside a fluorescent material film is coated, is covered with a shading film 8 except for a long and narrow light transmitting slit part 9 along the axial direction. The surface of the valve 2 to be covered with the shading film 8, including the slit part 9, is formed in the irregular structure by forming the crape surface or the like with frosting process or the like. The shading film 8 is thereby bonded to the surface of the valve 2 strongly, and while flickering of the light transmitted through the crape surface is reduced.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field)
The present invention relates to an aperture-type low-pressure discharge lamp in which a groove-shaped light transmitting portion is formed.

(Prior Art) Recently, attempts have been made to use low-pressure discharge lamps as direct display indicators on display panels of automobile meters, electrical equipment, and the like.

That is, a low-pressure discharge lamp such as a xenon glow discharge tube is shaped into an extremely thin hollow needle with an inner bulb diameter of about 21 to 3 mm, one end of this discharge lamp is attached to the rotating pointer shaft of the meter, and this rotating pointer is When the shaft rotates, the discharge lamp is also rotated together. According to this device, the discharge lamp functions as a pointer, and when the discharge lamp is turned on, it emits light itself and illuminates the display scale, so there are advantages such as no special illumination is required.

The discharge lamp used as the pointer of such a meter desirably has a light emitting part in the shape of an extremely thin needle. For this reason, this type of discharge lamp not only reduces the bulb diameter, but also forms a light transmitting part (hereinafter referred to as slit part) that is thinner than the bulb diameter along the bulb axis, creating a so-called aperture-shaped discharge lamp. It consists of This device emits light only from the light transmission slit portion along the bulb axis, and this light emitting portion is thinner than the diameter of the elongated bulb, so it has an extremely thin needle-shaped light emitting shape.

This type of discharge lamp has an internal electrode at one end of the bulb, and a band-shaped external electrode along the axial direction on the outer surface of the bulb, and high-frequency power is applied between these internal electrodes and the external electrode. is configured to generate a glow discharge within the bulb. Furthermore, xenon gas is sealed inside the valve.

(Problem to be Solved by the Invention) However, in the case of conventional discharge lamps of this type, the external electrode is provided along the bulb axis direction, so the distance from the internal electrode gradually changes, and therefore the potential gradient changes. Since the emission intensity is not uniform, flickering may occur in the light emitted from the light transmission slit section.

Further, in order to form the elongated light transmitting slit portion, a light shielding film made of synthetic resin or the like is formed on either the outer surface or the inner surface of the bulb.

In this case, the light-shielding coating is formed in direct contact with the surface of the bulb, but since the surface of the bulb is smooth, the coating has low adhesion strength and tends to peel off easily.

The present invention aims to provide an aperture-type low-pressure discharge lamp in which flickering of light emitted from a light-transmitting slit is prevented and the adhesion strength of a light shielding member is improved.

[Structure of the Invention] (Means for Solving the Problems) The present invention is characterized in that the surface of the bulb on which the light shielding member is provided is formed into an uneven surface such as a matte surface, and a light transmitting part is left in a long and narrow manner on this uneven surface. It is characterized by having a light shielding member attached thereto.

(Function) According to the present invention, since the surface of the bulb is made uneven, the light emitted to the outside from the light transmission slit is diffused and transmitted when passing through the bulb, thereby eliminating uneven brightness and flickering. Further, since the light shielding member is adhered to the uneven surface of the bulb, the contact area is increased, the adhesion strength is increased, and peeling of the light shielding member is prevented.

(Example) The present invention will be described below based on a first example shown in FIGS. 1 to 3.

In the figure, l indicates a low-pressure discharge lamp used as a pointer for an automobile speedometer or the like, and the discharge lamp 1 of this embodiment is a cold cathode discharge lamp. This discharge lamp 1 includes a glass bulb 2 in the shape of an elongated hollow rod, and the glass bulb 2 is formed into a needle shape, for example, with an outer diameter of 2.5 mm and a total length of about 60 mm.

As shown in FIG. 3, the outer surface of the bulb 2 is formed with an uneven surface 3 in the shape of a matte finish by frosting or other means.

A cold cathode 4 is sealed at one end of the bulb 2 as an internal electrode.
The cold cathode 4 is connected to a lead wire 5 that passes through the sealed end of the bulb 2 in an airtight manner.

A phosphor film 6 shown in FIG. 3 is formed on the inner surface of the bulb 2, and a discharge gas containing xenon as a main ingredient and at least one of neon, argon, and krypton is injected into the bulb 2 in parentheses. The pressure is 5 to 90 torr, preferably about 20 torr.

An external electrode 7 is provided on the outer surface of the bulb 2 in the form of a band along the axial direction. The external electrode 7 is constructed by applying a paste such as carbon phenol or silver epoxy in the form of a strip to a predetermined length of the bulb 2, and firing the paste.

The bulb 2 has a first power receiving terminal 10 formed in the form of a film on the outer surface of the end portion where the internal electrode 4 is sealed. The first power receiving terminal 10 is connected to a lead wire 4 that passes through the sealed end of the bulb 2 in an airtight manner, and is connected to the cold cathode 3 inside.

Further, on the outer surface of the bulb 2, the first power receiving terminal 10 is provided.
A second power receiving terminal 11 is formed at a position spaced apart from each other in the axial direction. The second power receiving terminal 11 is also made of a conductive paste such as silver epoxy, and is formed circumferentially spaced apart from the first power receiving terminal IO in the axial direction and having a predetermined width. This second power receiving terminal 11 is formed so as to avoid a slit portion 9 of a light shielding film 8, which will be described later, and is connected to an external electrode B.

A light-shielding coating 8 is formed on the outer surface of the bulb 2.

The light-shielding film 8 is applied to the outside of the uneven surface 3 of the bulb 2 by applying a solution consisting of carbon, epoxy resin, and adhesive and baking the solution.

This light-shielding coating 8 has a band-shaped opening extending in the axial direction, that is, a light-transmitting slit 9, located on the opposite side to the surface on which the external electrode 7 is provided. For this reason,
The light emitted from the bulb 2 is emitted to the outside only through the light transmitting slit 9 formed in the light-shielding coating 8, so that the cold cathode fluorescent lamp l has an aperture shape.

Note that the light shielding coating 8 has no coating formed on the portion facing the second power receiving terminal 1.1, and the second power receiving terminal 11 is directly exposed to the outside.

The cold cathode discharge lamp 1 configured in this way has a lamp holder 2.
Attached to 0.

The lamp holder 20 is made of an electrically insulating material and has a U-shaped cross section, and has first and second power supply terminal tongues 21 and 22 fixed thereto at a distance from each other in the longitudinal direction. These power supply terminal tongue pieces 21 and 22 are made by bending conductive leaf springs such as phosphor bronze into a substantially U shape, and the valve 2 is held by the clamping pieces 23a123b facing each other as shown by the imaginary lines in FIG. It is something to hold.

The lamp holder 20 is fixed to a pointer shaft 25 of the meter, and rotates integrally with the pointer shaft 25 when the pointer shaft 25 rotates.

Note that the pointer shaft 25 of this embodiment is constituted by a hollow shaft (not shown), and two covered cords (not shown) are inserted into this hollow pointer shaft 25, and one end of each of these covered cords is connected to the 1 and the second power supply terminal tongue piece 2], 2
2, and the other end is connected to a high frequency power source.

The cold cathode discharge lamp 1 is adapted to be attached to the lamp holder 20 at the end thereof where the internal electrode 4 is sealed. That is, the first power receiving terminal IO and the second power receiving terminal 11 formed on the outer surface of the bulb 2 are connected to the lamp holder 20.
The first power supply terminal tongue piece 21 and the second power supply terminal tongue piece 2 on the side
2 and push the lamp l from the opening side of the lamp holder 20, the first and second power supply terminal tongue pieces 2
1.22 clamping pieces 23a and 23b, respectively, clamp the first power receiving terminal IO and the second power receiving terminal 11 to mechanically support the valve 2. Therefore, the cold-shade discharge lamp 1 is fixed to the lamp holder 20. In this case, the first and second
Since the power supply terminal tongue pieces 2122 are in electrical contact with the first power receiving terminal 10 and the second power receiving terminal 11, respectively, the inner electrode 4 and the outer electrode 7 are Connected to high frequency power supply.

According to such a configuration, the cold cathode discharge lamp 1 is connected to the internal electrode 4 and the external electrode 7 from the first power receiving terminal 10 and the second power receiving terminal 11 via the first power feeding terminal tongue piece 21 and the second power feeding terminal piece 22. Since high frequency power is supplied to the bulb 2, a glow discharge is generated between the internal electrode 4 and the external electrode 7 within the bulb 2.

This glow discharge excites the xenon gas and causes it to emit ultraviolet light, and this ultraviolet light excites the phosphor wave film 5 to emit visible light. This light is originally emitted from the entire circumference of the bulb 2, but since the bulb 2 is covered with a light-shielding coating 8, a light-transmitting slit portion 9 formed in the light-shielding coating 8 is used.
It is only released to the outside.

Therefore, in addition to the bulb 2 being originally thin, the slit portion 9 exhibits an even narrower band of light, making this discharge lamp 1 suitable for indicating a display scale as a needle. Moreover, since it shines by itself, there is no need for any other special light source.

The lamp holder 20 is fixed to a pointer shaft 25, and when the pointer shaft 25 rotates, the lamp holder 20 is also rotated together, so the discharge lamp 1 attached to the lamp holder 20 is also rotated together. Therefore, the vehicle speed scale can be indicated by turning and moving to a position corresponding to the vehicle speed.

In this embodiment, since the uneven surface 3 is formed on the outer surface of the bulb 2, when the light emitted to the outside from the light transmitting slit section 9 passes through the bulb 2, it is diffused. This diffusion effect equalizes the areas with extremely high brightness and evens out flickering.

Further, since the light-shielding coating 8 adheres to the uneven surface 3 of the bulb 2, the contact area increases, the adhesion strength of the light-shielding coating 8 to the bulb 2 increases, and peeling of the light-shielding coating 8 is prevented.

Note that the present invention is not limited to the configuration of the first embodiment.

That is, in the first embodiment, the uneven surface 3 is formed on the outer surface of the bulb 2, and the light shielding film 8 is applied to the uneven surface 3 on the outer surface. As in the second embodiment shown in cross section, an uneven surface 3a may be formed on the inner surface of the bulb 2, and a light-shielding coating 8 may be applied between the uneven surface 3a and the phosphor coating.

Further, the light-shielding film 8 may be formed of a light-shielding tube 30 instead of a coating film, as in the third embodiment shown in FIGS. 5 to 8. This light-shielding tube 30
is made of synthetic resin or the like and has a tube shape with one end open, and is placed over the tip of the bulb 2 to cover almost the entire bulb 2. This light-shielding tube 30 has a band-shaped opening extending in the axial direction, that is, a light-transmitting slit 31 formed in advance. Therefore, the light from the bulb 2 is emitted to the outside only through the light-transmitting slit 31 formed in the light-shielding tube 30, and therefore the cold cathode fluorescent lamp 1 also has an aperture shape.

In this embodiment as well, the uneven surface 3 is formed on the outer surface of the bulb 2, and when the light emitted to the outside from the light transmission slit section 31 passes through the bulb 2, it is diffused. This diffusion effect equalizes extremely high brightness areas and also prevents flickering.

Moreover, since the light-shielding tube 30 is placed over the uneven surface 3 of the bulb 2, the contact area is increased, and the adhesion strength of the light-shielding tube 30 to the bulb 2 is increased.

Further, in the above embodiment, a cold cathode type rare gas discharge lamp used as a meter pointer has been described, but the present invention is not limited to this, and the present invention is not limited to a cold cathode type, but may also be a hot cathode type. A low pressure mercury fluorescent lamp may be used.

And it is also not limited to those that use external electrodes,
A pair of electrodes facing each other may be sealed at the end of the bulb.

If necessary, it may be a fluorescent lamp used for general illumination or OA equipment, as in the fourth embodiment shown in FIGS. 9 to 11.

In the case of the fourth embodiment shown in FIGS. 9 to 11 above,
Filament electrodes 51.51 at both ends of the linear bulb 50
are provided, and caps 52 and 52 are attached to the outside of both ends thereof. A cap bottle 53 protruding from each cap 52.52
．． 53 is connected to electrode 51.51.

A phosphor coating 54 is formed on the inner surface of the bulb 50, and mercury and argon gas are sealed inside the bulb 50.

An uneven surface 55 such as a frosted surface is formed on the outer surface of the valve 50.

A light-shielding tube 5B is provided on the outer surface of this bulb 50.
is covered. This light-shielding tube 56 is made of elastic synthetic resin, rubber, or the like, and has a light-transmitting slit portion 57 formed along the axial direction.

The light-shielding tube 56 of this embodiment has cutting lines 58 and 58 extending from the light-transmitting slit portion 57 to the end.

Therefore, both ends of the light-shielding tube 56 are opened at these cutting lines 58 and 58 as shown by imaginary lines in FIG. 9, and in this state it is attached to the outer surface of the bulb 50.

In this embodiment as well, an uneven surface 55 is provided on the outer surface of the valve 50.
When the light emitted to the outside from the light transmission slit portion 57 passes through the bulb 2, the light is diffused. This diffusion effect equalizes extremely high brightness areas and also prevents flickering.

Furthermore, since the light-shielding tube 56 is placed over the uneven surface 55 of the bulb 50, the contact area is increased, and the strength of the adhesion of the light-shielding tube 56 to the bulb 50 is increased.

Furthermore, if a reflective surface such as a light-reflecting coating is formed on the light-shielding coating or the inner surface of the tube in each embodiment, the light will be reflected by the reflective surface, thereby improving the light emission efficiency.

Further, in the discharge lamp of the present invention, the bulb is not limited to a straight shape, but may be curved.

[Effects of the Invention] As explained above, according to the present invention, since the uneven surface is formed on the outer surface or the inner surface of the bulb, when the light emitted to the outside from the light transmission slit portion passes through the bulb, The light is diffused by the uneven surface. This diffusion effect equalizes extremely high brightness areas and also prevents flickering. Furthermore, since the light-shielding coating or the light-shielding tube is adhered to the uneven surface of the bulb, the contact area increases, and the adhesion strength of the light-shielding coating or the light-shielding tube to the bulb is increased, reducing peeling and the like.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the present invention, FIG. 1 is an exploded perspective view of a discharge lamp used as a meter pointer and a lamp holder, and FIG. 2 is a plan view of the discharge lamp. 3 is a sectional view taken along the line ■-■ in FIG. 2, FIG. 4 is a sectional view showing a second embodiment of the present invention, and FIGS. For example, Figure 5 is an exploded perspective view of the discharge lamp, Figure 6 is an exploded perspective view of the discharge lamp and lamp holder, Figure 7 is a plan view of the discharge lamp, and Figure 8 is the middle of Figure 7. 9 to 11 show a fourth embodiment of the present invention, FIG. 9 is an exploded perspective view of the fluorescent lamp, FIG. 10 is an assembled perspective view, Figure 11 is the X in Figure 10.
It is a sectional view taken along line I-XI. ■... Cold cathode discharge lamp, 2... Bulb, 3... Uneven surface, 4... Internal electrode, 6... Fluorescent wave membrane, 7...
- External electrode, 8... Light-shielding coating, 9... Slit part,
3a... uneven surface, 30... light-shielding tube, 31.
...Slit part 50...Bulb, 51...Electrode, 5
5... Uneven surface, 56... Light-shielding tube, 57...
・Slit part. Applicant's representative Patent attorney Takehiko Suzue, Figure 1 Figure 2 Figure 4 L Figure 7 Figure 8 Figure 9 Figure 10 Figure 11

Claims (1)

[Claims] A bulb having a phosphor film formed on its inner surface is provided with electrodes, a luminescent substance is sealed inside the bulb, and a long and narrow light beam is provided on the inner or outer surface of the bulb along the axial direction of the bulb. In an aperture-type low-pressure discharge lamp in which a light-shielding member is provided leaving a light-transmitting part, and light is emitted to the outside from the light-transmitting part, the surface of the bulb on which the light-shielding member is provided is formed into an uneven surface, and the elongated light is formed on this uneven surface. An aperture-type low-pressure discharge lamp characterized in that a light-shielding member is coated with a transparent portion remaining.