JP2003121909A - Strobe substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a strobe device from getting faulty due to dielectric breakdown. SOLUTION: A waterproof and insulating protection layer 42 is formed on a strobe substrate 23 to which circuit parts such as a capacitor to be charged with a high voltage for light emission of a strobe are soldered. The protection layer 42 covers a resist film on a wiring pattern which has a high voltage at the time of charging the strobe, terminals of soldered circuit parts, and all the soldered parts to prevent dust, oil, and water stuck on the strobe substrate 23 from sticking to the terminals of the soldered circuit parts and the soldered parts and to prevent water from penetrating the resist film to reach the wiring pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strobe substrate having an insulating and waterproof protective layer in a high voltage region.

[0002]

2. Description of the Related Art A single-use type lens-fitted photo film unit in which an unexposed photo film is pre-loaded has been widely used. The lens-fitted film unit makes it easy to take pictures even if you are unfamiliar with the camera, and because it is compact and inexpensive, you can easily carry it around. Such a lens-fitted film unit generally has a built-in strobe device so that photographing can be performed at night or indoors.

A strobe device uses a substrate on one side of which a wiring pattern is formed and which is covered with a resist film. On this substrate, strobe circuit parts are assembled. The strobe substrate has a plurality of holes into which terminals of circuit components for strobes are inserted, and a wiring pattern is exposed in the periphery of the holes from a portion where the resist film is not formed. When the strobe circuit component is attached from the back side of the surface on which the wiring pattern is formed, it is soldered to the wiring pattern exposed around the terminal hole on the front side, electrically connected and fixed.

[0004]

However, in such a strobe board, the terminals of the circuit components soldered to the strobe board and the raised portions after soldering are exposed on the front side of the wiring pattern forming surface. If dust in the air, oil, or water adheres to it, dielectric breakdown is likely to occur. Further, in the portion to which a high voltage is applied, it is necessary to have a certain terminal spacing between components because dielectric breakdown is likely to occur, but the recent miniaturization of electronic components has made the terminal spacing between components insufficient. Therefore, there is a problem that creeping discharge is likely to occur.

The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a strobe substrate in which the strobe device is prevented from malfunctioning due to dielectric breakdown.

[0006]

In order to achieve the above object, the present invention provides at least a strobe substrate on which circuit components constituting a strobe circuit are mounted and which is provided with a wiring pattern and a resist film covering the wiring pattern. The resist film on the wiring pattern to which a high voltage is applied is covered with an insulating and waterproof protective layer. The protective layer is formed of silicon rubber or a curable resin and includes a wiring pattern to which a high voltage is applied, a wiring pattern around the wiring pattern and terminals of soldered circuit parts and soldered portions. By forming it in the region, it is possible to ensure the insulation and waterproof of the high voltage region.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a front perspective view of a lens-fitted film unit embodying the present invention. The taking lens 2 and the finder 3 are exposed on the front surface of the unit body. The strobe charging knob 4 is operated when performing stroboscopic photography and is provided to be slidable up and down.
When the strobe charge is completed, the light emitting diode is turned on inside, and the photographer can confirm this through the charge completion display window 5. When the shutter button 6 is pressed after the charging is completed, strobe light is emitted from the strobe light emitting section 7 at the same time as the shutter is operated.

A camera body 10 shown in FIG. 2 is housed inside the lens-fitted film unit 1. As is well known, the camera body 10 includes a shutter blade 11
A shutter mechanism for performing exposure by kicking the shutter blade, a shutter charge mechanism for generating a kicking force for kicking the shutter blade 11, and the like are provided.

The camera body 10 has a cartridge storage chamber 12 in which a cartridge from which a photographic film is drawn is stored.
A film roll storage chamber 13 for accommodating the drawn photographic film in a roll is integrally formed. The winding knob 14 engages with the spool of the cartridge at its lower end, and when the winding knob 14 is rotated for each photographing, the exposed film frame is moved toward the cartridge. In addition, the shutter charge is performed in accordance with this rotating operation, and the next shooting preparation is performed.

On the back surface of the shutter blade 11, a photographing opening 1 is provided.
A dark box in which 5 is formed is provided. At the rear of the dark box, an aperture that defines the exposure range of the subject light incident from the photographing opening 15 is formed, and the photographic film facing this is exposed. One end of the return spring 16 engages with the shutter blade 11, and the other end engages with the camera body 10. The shutter blades 11 are urged by a return spring 16 to a closed position that covers the photographing opening 15. On the front surface of the shutter blade 11, a lens holder 17, a taking lens 2, and a lens retainer 18 are sequentially arranged.

Various circuit components are attached to the back side of the strobe board 23 to form the strobe circuit shown in FIG. Each circuit component is soldered to a wiring pattern formed on the front surface side of the strobe board 23 to be electrically connected. On the front surface of the substrate, the wiring pattern other than the connection points of the circuit components is covered with a resist film to protect the wiring pattern.

The strobe device built in the lens-fitted photo film unit 1 will be described below with reference to FIGS. 3 and 4. Dry battery 24 to be the power source for the strobe
Are connected to the positive electrode side battery contact piece 25 and the negative electrode side battery contact piece 26.

Oscillation transistor 27 and oscillation transformer 28
The blocking oscillating circuit composed of is a boosting circuit that receives power from the dry cell 24 and generates a high voltage pulse, and charges the main capacitor 29 and the trigger capacitor 30 with a high voltage of about 300V. Oscillation transformer 2
8 is composed of a primary coil 28a, a secondary coil 28b, and a tertiary coil 28c.

A rectifying diode 31 is provided between the two capacitors 29 and 30 and the oscillating transformer 28 to prevent the reverse flow of the charging current. The magnitude of the current flowing through the main capacitor 29 and the trigger capacitor 30, respectively,
It is determined by the electric resistance value of the resistor 32.

The charging switch 33 is turned on when the strobe charging knob 4 is slid upward. When the charging switch 33 is turned on, the blocking oscillation circuit described above operates and the charging process is started. The light emitting diode 36 is connected to the dry cell 24 in parallel with the oscillation transformer 28 via the resistor 34 and the resistor 35. The light emitting diode 36 lights up when the charging process is close to completion, and this light is confirmed from the charging completion display window 5.

After the charging process, if the shutter button 6 is pressed while the charging switch 33 is in the ON state, stroboscopic photography can be performed. If the strobe charging knob 4 is slid downward and the charging switch 33 is turned off, normal shooting can be performed without the strobe lighting.

When the shutter button 6 is pressed for flash photography, the shutter blades 11 are kicked and rotated,
The photographing aperture 15 faces the photographing lens 2. At the same time, the head portion 11a of the shutter blade 11 turns on the synchro switch 37. When the synchro switch 37 is turned on, the electric charge stored in the trigger capacitor 30 is discharged, and as a result, a high voltage trigger voltage is generated in the trigger transformer 38. The trigger voltage excites the strobe light emitting tube 39, and the electric charge of the main capacitor 29 is discharged to the strobe light emitting tube 39.

When the strobe light emitting tube 39 is discharged from the main condenser 29, strobe light is emitted from the strobe light emitting section 7. The protection diode 41, which is connected to the base side and the emitter side of the oscillation transistor 27 with the resistor 40 interposed therebetween, protects the oscillation transistor 27 from discharge noise generated when the main capacitor 29 is discharged, and prevents performance deterioration and destruction. .

As shown in FIGS. 4 and 5, on the strobe substrate 23, a thick protective layer 42 is formed on the resist film 45. For the protective layer 42, for example, insulating and waterproof silicone rubber can be used. As shown by the shaded area in FIG.
It is provided on a resist film covering a wiring pattern connecting the high voltage end of No. 8 and the trigger capacitor 30, the trigger transformer 38, the main capacitor 29 and the stroboscopic arc tube 39. That is, at least between the secondary coil 28b and the trigger capacitor 30, between the secondary coil 28b and the trigger transformer 38, between the secondary coil 28b and the strobe arc tube 39, and between the secondary coil 28b and the main capacitor 29, Since the voltage becomes high during strobe charging, it must be waterproof and insulative. Further, the protective layer 42 is formed so as to cover not only the wiring pattern having a high voltage, but also the resist film on the wiring pattern around the wiring pattern and the terminals and soldered portions of the soldered circuit components. ing.

The strobe board 23 is built in with the wiring pattern 47 facing the front side of the lens-fitted film unit 1. For this reason, dust and oil in the air can be easily discharged from the gap between the strobe charging knob 4 and the strobe light emitting portion 7.
Although water easily enters and adheres to the strobe substrate 23, since the insulating and waterproof protective layer 42 is formed on the strobe substrate 23, the pinholes 46 on the resist film 45 and the resist film 45 have different thicknesses. The thin wiring pattern 47 does not penetrate from the vicinity of the edge 48 to the inside. Further, since the protective layer 42 covers the resist film on the high-voltage wiring pattern, the resist film on the wiring pattern around the high-voltage wiring pattern, and the terminals and soldered portions of the soldered circuit components, the protective layer 42 is charged by strobe charging. The high-voltage wiring pattern 47 is reliably protected from dust, oil, and water in the air adhering to the substrate, and creeping discharge between terminals is also prevented.

FIG. 6 shows an example of a method of forming the protective layer 42. In the strobe device, the strobe light emitting section 7 is assembled to the strobe board 23 at the final stage of its manufacture, and the strobe light emitting tube 39 and a required part of the strobe board 23 are electrically connected. Before assembling, the strobe substrate 23 is partially dipped in the solution 51 in which silicon rubber is melted in the posture shown in FIG. At this time, the tape 53 is attached to the land portion 52 that is electrically connected to the strobe light emitting unit 7. As shown in FIG. 6, the strobe substrate 23 is dipped in a solution, silicon rubber is attached to the high pressure generation portion of the strobe substrate 23, and then the strobe substrate 23 is pulled up and dried to perform the above-mentioned protection layer 4.
2 is obtained. Then, after the tape 53 is peeled off, the strobe light emitting section 7 may be assembled and electrically connected.

Before assembling not only the stroboscopic light emitting section 7 but also the positive electrode side battery contact piece 25 and the negative electrode side battery contact piece 26 of the dry battery, the charge switch 33 and the synchro switch 37 to the strobe board 23, each of the required parts is required. If the tape 53 is attached, the entire strobe substrate 23 can be dipped in the solution 51 to cover the entire strobe substrate 23 with the protective layer,
Moreover, positioning is not necessary when the strobe substrate 23 is dipped in the solution 51, and the manufacturing process is simplified. Then, the protective layer is dried, the tape 53 is peeled off, and the above-mentioned parts may be assembled.

The present invention has been described above according to the illustrated embodiment.
Other than silicone rubber, for example, an ultraviolet curable resin or a two-component curable resin (epoxy resin such as Araldite) can be used as long as it has waterproofness. Also, when forming the protective layer, coating,
Techniques such as spraying can be used. further,
The present invention can be widely applied not only to a lens-fitted film unit, but also to a normal photo camera, an instant camera, a digital camera, and the like.

[0024]

As described above, according to the strobe substrate of the present invention, the resist film on the wiring pattern to which a high voltage is applied by strobe charging and the terminals of the soldered circuit parts and the entire soldered part are provided. Since it is covered with a waterproof and insulating protective layer, even if dust, oil, or water in the air adheres to the substrate, the strobe device is prevented from malfunctioning or an electric leakage accident is prevented.

[Brief description of drawings]

FIG. 1 is an external perspective view of a film unit with a lens.

FIG. 2 is an exploded perspective view of a camera body.

FIG. 3 is a circuit diagram of a strobe device.

FIG. 4 is a front view showing the strobe board after mounting circuit components.

FIG. 5 is a sectional view of a strobe substrate.

FIG. 6 is a diagram showing a method for forming a protective layer.

[Explanation of symbols]

7 Strobe emission part 23 Strobe board 27 oscillation transistor 28 Oscillation transformer 29 Main capacitor 30 Trigger capacitor 38 Trigger transformer 39 Strobe arc tube 42 Protective layer 45 Resist film 47 wiring pattern 49 Circuit component terminals 50 Soldered part 51 solution 53 tapes

Claims (3)

[Claims] 1. A strobe substrate on which circuit components constituting a strobe circuit are mounted, and a wiring pattern and a resist film for covering the strobe circuit are provided. At least a resist film on a wiring pattern to which a high voltage is applied is insulated and waterproofed. A stroboscopic substrate characterized by being covered with a protective layer of a conductive property. 2. The protective layer is formed in a region including a wiring pattern to which a high voltage is applied, a wiring pattern around the wiring pattern, and a terminal and a soldered portion of a soldered circuit component. The strobe substrate according to claim 1. 3. The strobe substrate according to claim 1, wherein the protective layer is formed of silicon rubber or a curable resin.