JPS6348538A - Fitting mechanism for flash discharge tube - Google Patents

Abstract

PURPOSE:To perform accurate mounting by providing a spring member which engages the flank of reflecting umbrella at the end part and contacts a flash discharge tube at the center part, and pressing the discharge tube toward the bottom part of the reflecting umbrella by a spring member and holding the discharge tube at the bottom part of the reflecting umbrella. CONSTITUTION:Projections 16b for positioning are provided atop of three legs 16a of a trigger leaf spring 16 made of a spring material and the tip parts 16 of the legs 16a serve to control the quantities of insertion of the tip parts 16c of the legs 16a into three through holes 13a provided to the reflecting umbrella 13. Further, at least the outer periphery of the spherical round surface of the discharge tube 10 is coated with a transparent conductive film for a trigger electrode and made contact the trigger leaf spring 16. Consequently, the lead wire from a trigger trigger circuit is connected to the tip part of the trigger leaf spring 16 to trigger the discharge tube 10. The discharge tube 10 and reflecting umbrella 13 are positioned by a hole 13a where a cathode terminal 4 is inserted and a hole 13c where an anode electrode terminal 5 is inserted to provide the trigger electrodes securely.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a mechanism for attaching a microflash discharge tube to a strobe unit.

<Prior art> Conventionally, flash discharge tubes for strobes have a glass tube with a circular cross section filled with a rare gas such as xenon at a predetermined pressure.
A cathode electrode and an anode electrode are provided at both ends of a cylindrical straight glass tube, and tin oxide is the main component on the outer peripheral surface of the straight glass located between the tips of the anode electrode and the cathode electrode inside the glass tube. It has a structure in which a transparent conductive coating is applied and a trigger electrode is provided, and a fine wire such as a nickel wire is wound around the part of the glass tube coated with the transparent conductive coating as the lead wire for the trigger electrode. It has become.

When configuring the flash discharge tube according to the above configuration as a strobe unit, a concave reflective shade formed almost as a rotating surface is used to efficiently (irradiate) a predetermined range of flash light with respect to the optical axis of the flash discharge tube. is provided, and the flash discharge tube is disposed near or within the focal point inside the reflective shade.

The main body structure of the reflective shade on which the flash tube is written is synthetic resin with aluminum vacuum-deposited on the surface of the main body, or
Hikari 1 is made of mirror-finished metal such as aluminum, and has a pair of long-side reflective surfaces arranged parallel to the discharge tube and a pair of reflective surfaces arranged perpendicular to the discharge tube. When such a reflective shade is used, the light distribution characteristics of the irradiated light by the short side reflective surface are usually better than the light distribution characteristics of the irradiated light by the long side reflective surface. It's worse.

That is, there is a drawback that the utilization rate (yield) of light emitted from the flash discharge tube is poor. In order to correct this drawback, there is a method of increasing the depth of the reflective shade and increasing the frontage, but this method has the drawback of increasing the size of the electronic flash device.

As a way to solve the above-mentioned problem, by using a miniature flash discharge tube instead of a straight flash discharge tube and combining it with a reflective shade with a circular opening, a compact strobe unit with uniform light distribution characteristics can be provided. However, since the overall shape and electrode positions are completely different from those of the conventional straight pipe type, it has not been possible to attach it to the reflective shade in the same way as the conventional straight pipe type.

<Purpose> The present invention aims to provide a mounting mechanism that makes it easy to mount the bulb-type flash discharge tube to a reflective shade with uniform light distribution characteristics and improved accuracy.

<Example> Fig. 1 is a perspective view showing an example of a bulb-type flash discharge tube employed in the flash discharge tube mounting mechanism according to the present invention, and Fig. 2 (a) and (b) are top views and views thereof. It is a front view. Before explaining the attachment mechanism of the present invention, the bulb-type flash discharge tube will be explained.

In FIGS. 1 and 2, reference numeral 1 denotes a circular bottom plate made of ceramic, for example, and its outer periphery is surrounded by a glass tube 6 with a spherical tip indicated by a dashed line.

Shielding plates 7 and 8 are both made of ceramic or glass material, and the shielding plate 8 has a partially cut-off circular shape, and is arranged parallel to the bottom plate 1 at a predetermined distance. Moreover, the shielding plate 7 is vertically disposed approximately at the center of the bottom plate l. By combining the shielding plates 7 and 8 in this way, the inside of the glass tube can be divided into four chambers.

Further, a cathode electrode 4 and an anode electrode 5 penetrate through the bottom plate l, and a sintered electrode 4a of the cathode electrode is provided inside the glass tube 6.

Furthermore, a transparent conductive film containing tin oxide as a main component is coated on the outer peripheral surface of the glass tube 6 and acts as a trigger electrode. A rare gas such as xenon is sealed in the glass tube 6,
By applying a high voltage between the cathode electrode 4 and the anode electrode 5 and applying a trigger voltage to the trigger electrode, electrons are emitted along the path A-B-C in the figure to cause arc discharge and flash light emission.

FIG. 3 is an exploded perspective view showing one embodiment of a device mechanism for a reflecting shade for the bulb-type discharge tube shown in FIGS. 1 and 2, according to the present invention, and FIG. FIG.

In the figure, reference numeral 10 denotes a bulb-type discharge tube shown in the first diagram, which has a cathode electrode terminal 4 and an anode electrode terminal 5.

13 is a reflective shade made of synthetic resin, and aluminum 14 is vacuum-deposited on its inner surface. 15 is a protector placed on the front. 16 is a trigger leaf spring made of spring material, and has three legs 16a. A positioning protrusion 16b is provided at the tip of each leg 16a, and the tip 16c of each leg 16a is attached to the reflective shade 13.
It serves as a restriction for the inserter when inserted into the three through holes 13a provided in the.

The central portion of the trigger plate spring 16 is ring-shaped, and its inner peripheral hole 16d is fitted into the outer periphery of the spherical R surface at the tip of the discharge tube 10. Here, the diameter of the inner circumferential hole 16d is the diameter of the discharge tube 10.
It is made slightly smaller than the diameter of the Also, discharge tube 10
A transparent conductive film for a trigger electrode is coated on at least the outer periphery of the R surface of the sphere, and is brought into contact with the trigger plate spring 16 here. This makes it possible to trigger the discharge tube 10 by connecting a lead wire (not shown) from the strobe trigger circuit to the tip of the trigger plate spring 16. Further, a cylindrical portion 13d is provided below the reflective shade 13, and a hole 1 into which the cathode electrode terminal 4 is inserted.
3b and a hole 13c into which the anode electrode terminal 5 is inserted, and the discharge tube 10 and the reflective shade I3 are positioned by these two holes 13b and 13c. The trigger plate spring 16 regulates the position of the distal end of the discharge tube 10, thereby preventing the discharge tube 10 from wobbling due to vibration or the like.

<Effects> As explained above, the present invention provides a strobe unit using a bulb-type strobe discharge tube, in which the trigger electrode terminal is composed of a leaf spring and a transparent coating is applied to the outer wall of the rounded surface of the bulb at the tip of the discharge tube. As the leaf spring comes into contact with the conductive coating,
Since a biasing force is always applied in the direction of pressing the discharge tube against the reflector shade, the discharge tube can be stably held on the reflector shade with an extremely simple structure, and a reliable trigger electrode can be easily provided. It has the following.

Although multiple discharge tubes are shown in the embodiments, it goes without saying that any bulb-type discharge tube can be applied to the present invention.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a flash discharge tube used in the flash discharge tube attachment mechanism according to the present invention, FIG. 2(a),
(b) is a top view and a front view of the discharge tube shown in the first drawing, FIG. 3 is an exploded perspective view showing one embodiment of a strobe unit having the attachment mechanism of the present invention, and FIG. 4 is a strobe unit shown in the third drawing. FIG. 2 is a cross-sectional view of the assembled state. 10...Discharge tube, 13...Reflector shade, 16...Trigger plate spring. Patent applicant: Canon Co., Ltd.

Claims (1)

[Claims] A mounting mechanism for attaching a light-transmitting envelope having an opening at one end, a sealing plate that seals the opening of the envelope, and a flash discharge tube with cathode and anode electrode terminals arranged on the sealing plate to a reflective shade. A spring member is provided whose end portion engages the side surface of the reflective shade and whose center portion contacts the flash discharge tube, and the spring member presses the discharge tube toward the bottom of the reflective shade, A flash discharge tube attachment mechanism, characterized in that the discharge tube is held in the discharge tube insertion portion of the flash discharge tube.