JPH10294539A - Wiring structure for printing board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a jumper process without using a jumper wire or lead wire. SOLUTION: The printed board 35 has copper foil patterns 55 formed on its base material 35a and solder resist is printed thereupon to form an insulating layer 56. After the insulating layer 56 is formed, a carbon conductive pattern 57 is formed by printing carbon ink. The carbon conductive pattern 57 is formed on a connection land 58 in contact with its surface, on the base material 35a at the part of a conductive part 32a for light emission selection, and on the insulating layer 56 where they are connected, and electrically insulated from the copper foil pattern 55 below it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board wiring structure.

[0002]

2. Description of the Related Art As a printed circuit board on which various electric parts are assembled to form a circuit, a paper-based copper-clad laminate,
There are various types using glass-base copper-clad laminates, and these also include single-sided copper-clad laminates with a copper plate attached to one side of the substrate and double-sided copper-clad laminates with copper plates attached to both sides. .

For example, in a strobe device of a film unit with a lens manufactured and sold by the present applicant, in order to manufacture at low cost, a paper in which a copper plate serving as a wiring pattern is adhered to one surface of a paper base solidified with phenol resin. Printed circuit boards made from phenol single-sided copper-clad laminates are used. In the flash device of the lens-fitted film unit, an electrical component with a lead terminal is used as an electrical component of the flash circuit. However, in recent years, in order to reduce the size of the film unit with lens and increase the number of electric components due to the multi-function of the strobe circuit, an electric component with a lead terminal and a chip type electric component are currently used together. The mounting density of components is increased.

[0004] Further, when two circuits of the strobe circuit cannot be connected by a wiring pattern on a printed circuit board due to an increase in mounting density or complication of the strobe circuit, it is necessary to perform a jumper process. In this jumper processing, a jumper wire that is a metal wire without insulation coating on the printed circuit board,
Conventionally, a double-sided printed circuit board made of a double-sided copper-clad laminate is used for connection using a lead wire which is a metal wire provided with an insulating coating.

[0005]

However, when jumper processing is performed using a jumper wire, the jumper wire is inserted into a component insertion hole (through hole) of a printed circuit board by an inserter in the same manner as an electric component with a lead terminal. Automatic insertion and soldering make the manufacturing process relatively simple, but bare wires are routed on the component mounting surface (the surface with no wiring pattern) of the printed circuit board, which makes it difficult to connect with other components. Short circuits need to be considered. In addition, since the jumper wires are wired in a straight line, there is a problem that the jumper wires cannot be used when electric components are arranged in the middle of the wiring.

When a lead wire is used, since the lead wire is coated with an insulating material, there is no need to consider a short circuit with another component unlike a jumper wire. But,
Due to the structure of the lead wire, it is difficult to automatically insert the lead wire into the printed circuit board by the inserter, and there is a problem that the manufacturing process is complicated. In the case of a jumper wire and a lead wire, components that are not directly related to the strobe circuit are used, and there is a problem that extra component management costs are required.

Further, when a double-sided printed board is used, an expensive glass-epoxy double-sided copper-clad laminated board or the like obtained by hardening a glass cloth with an epoxy resin or the like is used as a base material in consideration of mechanical strength and electrical characteristics. Must be used. Further, in order to electrically connect the wiring pattern on the front surface and the wiring pattern on the back surface, it is necessary to form a copper through-hole, a silver through-hole, and the like on the printed circuit board.

For example, in the case of a copper through-hole, this can be used as a through-hole (component insertion hole) for inserting a lead terminal of a metal film resistor, a diode, a transistor, or the like, so that the printed board space is reduced. Although it can be used effectively, as is well known, copper through-holes need to be formed on a printed circuit board by a tenting method, a secondary copper solder peeling method, or the like. There is a problem that led to a rise.

On the other hand, in the case of a silver through-hole, the number of manufacturing steps is smaller than that of a copper through-hole, so that the manufacturing cost can be reduced accordingly. However, this silver through-hole can be used as a component insertion hole. Can not. Therefore, it is necessary to separately provide a silver through hole and a component insertion hole, which is disadvantageous in terms of space.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and can reduce the management cost of components to be assembled on a printed circuit board, improve the efficiency of assembling the components, and manufacture a printed circuit board. It is an object of the present invention to provide a printed circuit board wiring structure that does not reduce efficiency.

[0011]

In order to achieve the above object, according to the first aspect of the present invention, a carbon conductive pattern is formed on the surface of a printed circuit board as a part of circuit wiring, and the carbon conductive pattern is At least a portion of the wiring pattern to be electrically insulated is formed on the insulating layer, and a portion of the wiring pattern to be electrically connected is formed on the surface of the wiring pattern. According to a second aspect of the present invention, the insulating layer is made of a solder resist. In a third aspect of the present invention, the carbon conductive pattern is formed by printing after forming the insulating layer.

[0012]

FIG. 2 shows an appearance of a film unit with a lens according to the present invention. The lens-fitted film unit 10 includes a unit body 11 containing a simple photographing mechanism and an unexposed photographic film, and a label 12 covering a part of the unit body 11. Label 12
Is a photographing lens 13, a finder 14, and a winding knob 1.
5, the shutter button 16, the strobe light emitting section 17, and the like are wound so as to be exposed.

On the right side of the front of the unit body 11, a strobe light emitting section 17 is provided, and below it, a light emitting selection button 18 and a charging button 19 are provided. By pressing the charge button 19, the main capacitor 30 (see FIG. 3) is charged. In the film unit 10 with the lens, if the charging button 19 is pressed once, the charging is continued until the main capacitor 30 reaches the specified charging voltage even if the pressing of the charging button 19 is released immediately thereafter. Is recharged every time Therefore, it is not necessary to operate the charge button 19 for each photographing, and the charge button 19 is pressed only when the charge voltage of the main condenser 30 is low.

Further, in a state where the main condenser 30 is charged, by pressing the shutter button 16 while pressing the light emission selection button 18 to perform shooting, it is possible to perform flash shooting with strobe light emission. If the photographing is performed without pressing the light emission selection button 18, even if the main condenser 30 is charged, the photographing can be performed without firing the strobe light.

As shown in FIG. 3, the unit body 11 comprises:
The cartridge 20a of the film cartridge 20 and the photographic film 2 pulled out from the cartridge 20a
0b, and the main body base 21
An exposure unit 22 and a strobe device 23 mounted on the front of the exposure unit 2 and an exposure unit 2 mounted on the front of the main body base 21.
2 and a front cover 24 for covering the strobe device 23; a rear cover 25 attached to the back side of the main body base 21 for optically storing the photo film 20b between the main body base 21; and a power source for the strobe device 23. And a battery 26 and the like.

The exposure unit 22 includes a counter mechanism for displaying the number of frames that can be photographed, a shutter mechanism, a one-frame feed mechanism for feeding a photographic film one frame at a time, and a photographic lens 1.
3, and the finder 14 are unitized.

The main body 21 has a cartridge chamber 21a in which the cartridge 20a is loaded and a cartridge chamber 21a.
a, a film storage chamber 21b for storing a roll of unexposed photographic film 20b drawn out of a. These bottom surfaces are openings, and are closed by bottom covers 25a and 25b formed on the rear cover 25. The bottom lid 25a of the cartridge chamber 21a is openable and closable by engagement of a claw. After the photographing of all the frames of the photographic film 20b is completed, a bottom cover for taking out the cartridge 20a containing the photographed photographic film 20b is provided. Become.

A winding knob 15 is rotatably disposed above the cartridge chamber 21a. This winding knob 1
5 is rotated in the counterclockwise direction in the drawing, the photographed photo film 20b is taken in the cartridge 20a, and the unexposed portion is pulled out of the film storage chamber 21b, and set behind the aperture 21c. Is done.

The release button 16 is integrally formed on the upper surface of the front cover 24. Also, the front cover 24
An opening for exposing the photographing lens 13, the finder 14, and the strobe light emitting unit 1 is formed on the front surface of the camera, and a light emission selection button 18 and a charge button 19 are integrally formed.

As shown in FIG. 4, the strobe device 23 comprises
A strobe light emitting unit 17, electric components such as a main capacitor 30 constituting a strobe circuit, a battery 26, a pair of electrode plates 29a and 29b for holding the battery 26 and connecting to the strobe circuit, a synchro switch 31, a light emission selection. Switch 32 and charge switch 33
It is the one that is assembled.

As the printed circuit board 35, in order to manufacture the film unit 10 with a lens at low cost, a paper phenol obtained by attaching a copper plate to one surface (surface) of a base material 35a (see FIG. 1) obtained by solidifying a paper material with a phenol resin is used. Manufactured using single-sided copper-clad laminates. By etching a copper plate on the surface side of the printed circuit board 35, a copper foil pattern as a wiring pattern to be a wiring of a strobe circuit is formed, and a conductive carbon is printed by printing carbon ink. A conductive pattern is formed.

The strobe light emitting section 17 is provided with a printed circuit board 35.
A plastic holding member 17a attached to the
A reflector (not shown) incorporated in and held by the holding member 17a, a strobe discharge tube 17b, and a trigger electrode 1
7c (see FIG. 6) and a diffusion plate 17d for diffusing the strobe light from the strobe discharge tube 17b.

The sync switch 31 is connected to the printed circuit board 3.
5, the upper metal piece 31a of the two metal pieces 31a and 31b arranged at an appropriate interval vertically is elastically deformed when the shutter blade is fully opened, It is turned ON by contacting the lower metal piece 31b.

The charging switch 33 includes charging conductive portions 33a and 33b formed on the surface of the printed circuit board 35, and a charging metal contact 33c disposed behind the charging button 19. When the charging button 19 is depressed, the charging switch 33 is elastically deformed and the charging metal contact piece 33c comes into contact with the charging conductive portions 33a and 33b, and is electrically connected to turn on. Becomes

As shown in FIG. 5, the light emitting selection switch 32 includes a light emitting selecting conductive portion 32a formed on the surface of the printed circuit board 35, and a light emitting selecting metal contact piece 32b having elasticity.
Consists of One end of the light emitting selection metal contact piece 32b is inserted into the component insertion hole 36, and the light emitting selection land 3
2c (copper foil pattern), and the other end is disposed at an appropriate distance from the light emitting selection conductive portion 32a. The other end of the light-emitting selection metal contact 32b is pressed by the light-emission selection button 18 so that the other end thereof is turned on.
Touch 2a. As a result, the light emission selection switch 33 is turned ON.

FIG. 6 shows a circuit configuration of the strobe device 23. The oscillating transistor 40 and the oscillating transformer 41 constitute a known blocking oscillating circuit, convert the low voltage of the battery 26 to a high voltage, for example, 300 V, and charge the main capacitor 30 with this high voltage. Once the oscillating transistor 40 is activated, the latching transistor 42 is turned on to supply a feedback current to the oscillating transistor 40, so that the oscillating transistor 40 continues to oscillate even when the charging switch 32 is turned off. Continue charging.

When the main capacitor 30 is charged to a specified charging voltage, for example, 300 V, the Zener diode 43 supplies a Zener current to turn on the stop transistor 44.
To When the stop transistor 44 is turned on, the input terminals (base terminal and emitter terminal) of the oscillation transistor 40 are short-circuited, and the operation of the oscillation transistor 40 stops. Further, with the stop of the operation of the oscillation transistor 40, the latch transistor 42 is turned off.
Thereby, the charging is stopped when the main capacitor 30 is charged to the specified charging voltage.

The trigger capacitor 45 is charged by the above-described blocking oscillation circuit or the charged main capacitor 30 when the light emission selection switch 32 is ON. The trigger capacitor 45 discharges when the sync switch 31 is turned on while the light emission selection switch 33 is turned on, and causes the discharge current to flow as the primary current of the trigger coil 46.

When the primary current flows, the trigger coil 46 generates a trigger voltage of, for example, 4 KV in the secondary coil.
This trigger voltage is applied to the strobe discharge tube 17b via the trigger electrode 17c. By applying this trigger voltage,
The electric charges charged in the main capacitor 30 are discharged in the strobe discharge tube 17b, and strobe light emission is performed.

In the neon tube 47, the main capacitor 30 is charged to the specified charging voltage, and the light emission selection switch 33 is turned on.
Lights when N is set. The light from the neon tube 47 passes through a finder 14 through a light guide (not shown).
The photographer can check that the neon tube 47 is lit in the viewfinder 14 to know that strobe light emission is ready.

Reference numeral 48 denotes a rectifying diode for rectifying the secondary current of the oscillation transformer 41 and supplying power to the main capacitor 302. Reference numeral 49 denotes a capacitor that discharges after the strobe light is emitted and automatically restarts the oscillation transistor.

In the strobe device 23 having the above circuit configuration, as shown in FIG. 7, a latching transistor 42, a zener diode 43, a stopping transistor 44, various resistors,
A chip component 50 such as a capacitor is directly soldered to a chip land 51 (see FIG. 8) provided on the surface side of the printed circuit board 36, so that it is surface-mounted.

The main capacitor 30, the oscillation transistor 40, the oscillation transformer 41, the trigger capacitor 45, the trigger coil 46, the neon tube 47, and the rectifier diode 48
The electric component with lead terminal 52 is disposed on the back surface of the printed circuit board 35. Each of the components 52 with lead terminals has its lead terminal passed through a component insertion hole 53 formed in the printed circuit board 35, and a lead terminal land 54 (formed around the component insertion hole 53 on the surface of the printed circuit board 35). (See FIG. 8).

Further, on the front side of the printed circuit board 35,
A cyclo switch 31, a light-emitting selection metal contact piece 32b, and a negative electrode plate 29b are mounted on the back surface, and a positive electrode plate 29a is mounted on the back surface, and are soldered to corresponding lands. The strobe light emitting unit 17 is attached from the side of the printed circuit board 35, and both terminals of the strobe discharge tube 17b and the trigger electrode 17c are connected to circuits on the printed circuit board 35 using lead wires or metal pieces.

FIG. 8 shows the surface of the printed circuit board 35. In FIG. 8, different types of hatching are drawn on the portion where the insulating layer is not formed and on the portion where printing with carbon ink is performed.

The printed circuit board 35 includes an insulating base material 35.
A large number of copper foil patterns 55 based on the strobe circuit shown in FIG. 6 are formed on a. These copper foil patterns 5
On the surfaces of the substrate 5 and the base material 35a, an undercoat is applied in the same manner as a conventional printed circuit board, and then a solder resist is printed to form an insulating layer 56 (see FIG. 1). In addition, the insulating layer 56 is not formed in portions such as the chip lands 51 and the lead terminal lands 54 formed in the copper foil pattern 55, and the copper foil pattern 55 is exposed, so that each chip component 50 and each Electrical component with lead terminal 5
The two lead terminals can be soldered.

The copper foil pattern 55 of the printed circuit board 35
Since the pattern of the light emission selection switch 32 is added by slightly changing the pattern of the conventional strobe device, the trigger capacitor 45 and the neon tube 47 are subjected to a jumper process, and the light emission selection conductive The part 32a and the copper foil pattern 55 must be connected. For this reason, a conductive carbon conductive pattern 57 is formed on the surface of the printed board 35 to perform a jumper process. This carbon conductive pattern is formed by printing using, for example, a carbon paste having high conductivity.

One end of the carbon conductive pattern 57 is a conductive portion 32a for light emission selection. The connection land in the copper foil pattern 55 to which the trigger capacitor 45 and the neon tube 47 are connected from the conductive portion 32a for light emission selection. The connection conductive portion 57a extends on the top surface 58 and has the other end in close contact with the surface of the connection land 57 and is electrically connected thereto.

The insulating layer 56 is not formed in the lower layer (the upper layer of the base material 35a) of the light emitting selection conductive portion 32a and the lower layer (the upper layer of the connection land 58) of the connection conductive portion 57a. The portion of the carbon conductive pattern 57 between the light emitting selection conductive portion 32a and the connection conductive portion 57a is
Are formed so as to pass through the copper foil pattern 55 indicated by the broken line in the figure, avoiding the chip lands 51 and the lead terminal lands 54 where no lands are formed. In order to electrically insulate the carbon conductive pattern 57 from the copper foil pattern 55 through which the carbon conductive pattern 57 passes, the carbon conductive pattern 57
Is formed on the insulating layer 56 (surface). In addition,
The light emitting selection conductive portion 32a may be formed on the insulating layer 56.

FIG. 1 schematically shows the layer structure of the printed circuit board 35 between the light emitting selection conductive portion 32a and the connection conductive portion 58a. The connection conductive portion 57a is formed in close contact with the surface of the connection land 58, and the light emission selection conductive portion 32a is formed as a part of the carbon conductive pattern 57 on the surface of the base material 35a. These connection conductive portions 57
a and the light-emitting selection conductive portion 32a are connected to the base material 35a
And on the insulating layer 56 formed on the copper foil pattern 55.

As a result, the carbon conductive pattern 57
Electrically connects the copper foil pattern 55 formed therebelow, the connection lands 58, that is, the trigger condenser 45 and the neon tube 47, and the light emitting selection conductive portion 32a in an electrically insulated state. ing. Therefore, this carbon conductive pattern 57 constitutes a wiring surrounded by a broken line of the strobe circuit in FIG.

As described above, since the jumper process is performed by the carbon conductive pattern 57, the conventionally used jumper wires and lead wires can be reduced, and the parts management cost can be reduced. Therefore, the cost of the film unit with lens 10 can be reduced. Further, since the number of component insertion holes and lands for jumper wires and lead wires can be reduced, the degree of freedom in pattern design of the copper foil pattern 55 increases, and the pattern itself can be simplified. This is advantageous in reducing the size of the resulting strobe device 23.

In the film unit 10 with a lens, as shown in FIG. 8, the charging conductive portions 33a and 33b of the charging switch 33 are also formed by printing carbon ink on the surface of the copper foil pattern 55. But,
The charging conductive portions 33a and 33b may be formed by exposing the copper foil pattern 55.

When flash photography is performed in the film unit with lens 10 configured as described above,
The charge button 19 is pressed to prepare for shooting. The pressing operation of the charging button 19 may be immediately released. When the charging button 19 is pressed, the charging metal contact piece 33c of the charging switch 33 disposed behind the charging button 19 is
5 is in contact with each of the charging conductive portions 33a and 33b. Thereby, the charging metal contact piece 33c and the charging conductive part 33a,
The respective copper foil patterns 55 in the lower layers of the charging conductive portions 33a and 33b are electrically connected via 33b, and the charging switch 32 is turned on.

When the charging switch 33 is turned on, the oscillation transistor 40 starts operating and oscillates by the feedback action of the oscillation transformer 41. Due to the oscillation, a high voltage is generated on the secondary side of the oscillation transformer 41, and the main capacitor 30 is charged with the secondary current flowing by the high voltage. The oscillating transistor 40 oscillates continuously even after the charging switch 33 is turned off since the latching transistor 42 is turned on in response to the start of the operation.

When the main capacitor 30 is charged to the specified charging voltage, a zener current flows through the zener diode 43 and the stop transistor 44 is turned on. When the stop transistor 44 is turned on, the oscillation transistor 40 stops, and accordingly, the latch transistor 4
2 becomes OFF. Thereby, charging stops.

After the start of charging, the light emission selection button 18
Is pressed. When the light emission selection button 18 is pressed, the light emission selection metal contact piece 32b whose one end is connected to the ground (minus side of the battery 26) via the copper foil pattern 55
Is in contact with the conductive portion 32a for light emission selection of the carbon conductive pattern 57.

As a result, the light emission selection button 32 is turned on. The carbon conductive pattern 57 is
a, through the connection land 58, through the trigger capacitor 45,
Since it is electrically connected to one end of the neon tube 47, the trigger capacitor 45 and one end of the neon tube 47 are grounded when the light-emitting selection metal contact piece 32b comes into contact with the light-emitting selection conductive portion 32a. 45 is charged, and the charging voltage of the main capacitor 30 is applied to the neon tube 47. If the light emission selection switch 32 is turned on while the main capacitor 30 is being charged, the trigger capacitor 45 is charged by the charging voltage of the main capacitor 30 and the high voltage generated by the oscillation transformer 41, and is turned on after the charging is completed. Then, the battery is charged with the charging voltage of the main capacitor 30.

As described above, the light emission selection switch 32
When the main capacitor 30 is charged to the specified charging voltage in a state where is turned ON, the neon tube 47 is turned on. The light of the neon tube 47 is guided into the finder 14 through a light guide. Then, after confirming the lighting of the neon tube 47 in the finder 14, the shutter release is performed by pressing the release button 16 while pressing the light emission selection button 18.

When the shutter is released, the shutter blades provided in the exposure unit 22 swing. When the shutter blades are fully opened, the synchro switch 31 is turned on, and at this moment the trigger capacitor 45 is discharged, and the trigger voltage generated in the trigger coil 46 by this discharge is applied to the strobe discharge tube 17b via the trigger electrode 17c. Is done. As a result, the electric charges charged in the main capacitor 30 are discharged in the strobe discharge tube 17b, and the strobe discharge tube 17b emits light. This strobe discharge tube 17b
Is diffused by the diffusion plate 17d and irradiated toward the subject.

After the strobe light is emitted, even if the charging switch 32 is not turned on, the oscillation transistor 40 starts to operate by discharging the capacitor 49, and the main capacitor is charged 30 in the same manner as described above. When flash photography is not performed, the release button 16 may be pressed without pressing the light emission selection button 18. As described above, if the light emission selection button 18 is not pressed, the light emission selection switch 32 is turned off. Therefore, even if the synchro switch 31 is turned on, the trigger capacitor 45 does not discharge, so that no strobe light emission is performed.

Next, the operation of the above configuration will be briefly described. The film unit with lens 10 is
During the transportation of the unit body, the exposure unit 22, the strobe device 23, the film cartridge 20 and the like manufactured on different manufacturing lines are assembled to the main body base 21, and the front cover 24 and the rear cover 25 are further attached. 11 is completed. Then, the label 12 is wound around the unit main body 11, whereby the film unit with lens 10 is completed.

In manufacturing the printed circuit board 35 of the strobe device 23, an etching resist printing step, an etching step, a resist removing step, a solder resist printing step, a carbon printing step, and an outer shape processing step are sequentially performed.

First, in the etching resist printing step, a single sheet of paper phenol single-sided copper-clad laminate serving as a base for a plurality of printed boards 35 whose copper plates have been flattened should be formed on the surface of the printed board 35. Various lands 51,5
An etching resist is printed on each copper foil pattern 55 including 4, 57a. Then, in the paper phenol single-sided copper-clad laminate on which the etching resist is printed, portions other than the portion on which the etching resist is printed are removed by an etching process in the etching process, and a predetermined copper foil pattern 55 is formed on the base material 35a. It is formed.

In the paper phenol single-sided copper-clad laminate on which the copper foil pattern 55 is formed, all the etching resist on the copper foil pattern 55 is removed in a resist removing step.
After the copper foil pattern 55 is exposed, it is sent to a solder resist printing step. In the solder resist printing step, an undercode agent is applied to the paper phenol single-sided copper-clad laminate on which the copper foil pattern 55 is exposed, and then a solder resist for preventing the solder from adhering is printed. Of course, in this solder resist printing,
The copper foil pattern 55 is printed on the entire surface of the copper foil pattern 55 and the surface of the base material 35a except for the lands 51, 54, 57a and the conductive portions 32a, 33a, 33b. By the printing of the solder resist, the insulating layer 56 is formed in a portion where the solder resist is printed. The paper phenol single-sided copper-clad laminate on which the insulating layer 56 is formed in this manner is sent to a carbon printing process.

The paper phenol single-sided copper-clad laminate sent to the carbon printing step is printed with the carbon conductive pattern 57 and the charging conductive portions 33a and 33b using a carbon paste. By the printing of the carbon conductive pattern 57, the conductive portion 32a for light emission selection is formed on the surface of the base material 35a, and the conductive portion 57a for connection is formed on the surface of the land 58 for connection. 57a
Are electrically connected by the carbon conductive pattern 57 formed therebetween.

Of course, the carbon conductive pattern 57
Each land 51, 5 where the insulating layer 56 is not formed on the surface
4 and the copper foil pattern 55 to be electrically insulated is formed on the surface of the insulating layer 56, so that the carbon conductive pattern 57 is formed on the copper foil pattern 55 other than the connection lands 58. It is not electrically connected to

In the outer shape processing step after the completion of the carbon printing, the printed circuit boards 35 are punched out one by one from the paper phenol single-sided copper-clad laminate using a mold, and the component insertion holes 36, 53 and Various holes such as mounting holes for attaching the strobe device 23 to the main body base 21 are drilled at predetermined positions, and the printed circuit board 35 is completed.

By the way, there are many restrictions on the processing of a die punch for forming the component insertion hole 53. For this reason, the position of the component insertion hole 53 of the printed circuit board 35 is restricted. However, since the component insertion hole for the jumper is unnecessary, the degree of freedom of the position of the component insertion hole 53 can be increased. Further, since the number of holes formed in the printed board 35 is reduced, there is an advantage that the strength of the printed board 35 is increased. Furthermore, the die for punching can be manufactured at a low cost because there is no need to provide a component insertion hole for a jumper.

Further, the printed circuit board 35 manufactured as described above requires only half the number of manufacturing steps as a double-sided printed circuit board, and it is not necessary to form copper through holes and silver through holes. This is advantageous in that the manufacturing cost is reduced. As a result, the printed circuit board 35 requires a process for printing the carbon conductive pattern 57, but since this process itself is relatively simple, it can be manufactured efficiently.

As described above, the completed printed circuit board 35 is sent to a component assembling step. In the component assembling step, first, a chip component 50 such as a latch transistor 42, a zener diode 43, a stopping transistor 44, a resistor and a capacitor is mounted on a chip land 51 formed on the surface of the printed circuit board 35 by using a predetermined adhesive. Temporarily attached. Next, the main capacitor 30 and the oscillation transformer 4
1, electrical components 52 with lead terminals, such as the trigger condenser 46 and the trigger transformer 46, are temporarily mounted by passing the lead terminals through the component mounting holes 53 from the back side of the printed circuit board 35.

The printed circuit board 35 on which the chip parts 50 and the electric parts 52 with lead terminals are temporarily mounted is soldered to the chip lands 51 and the lead terminal lands 54 by a known flow soldering method (dip method) or the like. Attached. At this time, although the solder does not adhere to the carbon conductive pattern, there is no problem if the solder adheres. Thereafter, a synchro switch 31, a strobe light emitting unit 17, a pair of electrode plates 2
9a, 29b and the metal contact piece 32b for light emission selection are mounted and soldered, and the strobe device 23 is completed. of course,
Since the jumper processing is performed by printing a carbon conductive pattern, a step of soldering a champer wire or a lead wire is unnecessary. Therefore, the strobe device 23
Can be assembled efficiently.

The completed strobe device 23 is supplied to the assembly line of the unit main body 11 after inspecting soldering, and is attached to the front surface of the main body base 21. Most of the mounting failures of the components of the printed circuit board are soldering failures. However, since it is not necessary to solder the champer wires and the lead wires, the mounting failures are reduced.

In the above embodiment, the conductive portion for light emission selection, which is in contact with the metal contact piece for light emission selection, was formed of carbon ink. However, this conductive portion for light emission selection was formed as a copper foil pattern on which no insulating layer was formed. It is also possible to configure so that the carbon conductive pattern is connected to a part of the copper foil pattern.

In the above embodiment, an example was described in which only one end of the carbon conductive pattern was connected to the land (copper foil pattern). However, the carbon conductive pattern can be used as another wiring for jumper processing. . For example, a carbon conductive pattern can be used as a wire for permanent connection between two points (two copper foil patterns) of a strobe circuit.

In the above embodiment, the film unit with a lens has been described. However, the present invention can be applied to a printed circuit board of a strobe device such as a camera, and the present invention can be applied to other printed circuit boards of a strobe device. be able to.

[0067]

As described above, according to the present invention,
A carbon conductive pattern is formed on a printed circuit board by printing carbon ink, and a portion of the carbon conductive pattern that is to be electrically insulated from the wiring pattern is formed on an insulating layer, and the wiring to be electrically connected is formed. Since the carbon conductive pattern is formed as a part of the wiring of the circuit in the portion on the pattern formed on the surface of the wiring pattern, jumper processing can be performed without using a jumper wire or a lead wire. Further, since it is not necessary to form copper and silver through holes unlike a double-sided printed board, the manufacturing efficiency of the printed board is not reduced. Further, it is possible to reduce the number of components to be mounted on the printed circuit board and to reduce the component management cost. At the same time, it is possible to improve the efficiency of mounting components to the printed circuit board by reducing the number of components.

[Brief description of the drawings]

FIG. 1 shows a layer structure of a printed circuit board embodying the present invention.

FIG. 2 is a perspective view showing an appearance of a film unit with a lens.

FIG. 3 is an exploded perspective view showing the unit main body in an exploded manner.

FIG. 4 is a perspective view showing a strobe device.

FIG. 5 is a perspective view showing a light emission selection switch.

FIG. 6 is a circuit diagram showing a circuit configuration of a strobe device.

FIG. 7 is an exploded perspective view showing an exploded flash device.

FIG. 8 is an explanatory diagram showing a surface of a printed circuit board of the strobe device.

[Explanation of symbols]

 Reference Signs List 23 Strobe device 32 Light emission selection switch 32a Light emission selection conductive part 32b Light emission selection metal contact piece 35 Printed circuit board 35a Base material 51, 54 Land 53 Component insertion hole 55 Copper foil pattern 56 Insulating layer 57 Carbon conductive pattern 57a Connection conductive part 58 Connection Land

Claims (3)

[Claims] An insulating base material, a plurality of conductive wiring patterns formed on the surface of the base material, and an insulating layer formed in a predetermined pattern on the surface of the base material and the wiring pattern. A printed circuit board using the wiring pattern as a circuit wiring, wherein a carbon conductive pattern is formed on a surface of the printed board as a part of the circuit wiring, and at least the carbon conductive pattern should be electrically insulated. Forming a portion of the wiring pattern on the insulating layer;
The wiring structure of a printed circuit board, wherein a portion of the wiring pattern to be electrically connected is formed on a surface of the wiring pattern. 2. The wiring structure according to claim 1, wherein the insulating layer is a solder resist. 3. The wiring structure of a printed circuit board according to claim 1, wherein the carbon conductive pattern is formed by printing after forming the insulating layer.