JP2003302543A - Opto-electric circuit and opto-electric wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an opto-electric circuit whose manufacturing process can be simplified. <P>SOLUTION: The circuit has in the information transmission line thereof either of a means for conversion from an electric signal to an optical signal and a means for conversion from an optical signal to an electric signal is provided. In this circuit 1, the transmission line is formed of a material which has transmissivity of the optical signal and conductivity (e.g. ITO, ZnO, In<SB>2</SB>O<SB>3</SB>, SnO<SB>2</SB>, ITO, AZO, ATO, FZO, FIO, or FTO) and the optical signal and electric power or the optical signal and electric signal are transmitted through the transmission line at the same time. Thus, the optical signal and electric power or the electric signal can be transmitted through the transmission line at the same time, and consequently the need to form a wire for electric power supply is eliminated to simplify the manufacturing process. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit for transmitting information by light and its wiring board.

[0002]

2. Description of the Related Art In recent years, electronic circuit boards are multi-layer circuit boards in which circuits are laminated on a double-sided board having circuits formed on both sides from a single-sided board having circuits formed on only one side thereof in order to realize miniaturization and high performance. The number of substrates with advanced multi-layers is now widely used.

The manufacture of the multilayer substrate will be described below.
First of all, in the manufacturing process of a multi-layer substrate, copper foil is attached to both sides of a substrate material called prepreg which is made by impregnating glass cloth with epoxy and dried, and a dry film is laminated on this copper foil, followed by exposure, development and copper foil. The double-sided plate is formed through the steps of etching and dry film removal. Next, the double-sided plate and the prepreg are alternately laminated and integrated by heating and pressing. After that, a hole is formed at a desired position, and then the inner surface of the hole is plated to ensure electrical continuity between the layers. The holes of this circuit board are usually formed one by one by a drill or a punching machine, but high-speed holes may be processed by a laser for cost reduction.

In the laser drilling, it is necessary to set conditions such as laser wavelength, output and pulse width.
Therefore, in drilling holes such as FRP substrates that are made by compounding glass fibers such as reinforcing materials and aramid fibers with epoxy resin,
In order to secure the workability corresponding to the sub-component on the machined surface, the output, pulse width, etc. are changed to adjust the conditions, thereby improving the yield.

Further, in the step of pressing and filling the paste into the via holes or through holes which have been machined, a printing method using a filling head called a squeegee is used. In this printing method, squeegee hardness, angle, printing pressure,
Since it is necessary to set extremely many conditions such as the speed of the filling operation, and a slight difference in settings affects the quality, adjustments are made based on experience at the manufacturing site, and the yield in the paste filling process, Improving quality. In addition, in the paste filling process, squeegees have been devised, and not only squeegees such as a flat squeegee, a sword squeegee, and a squeegee with a curved contact portion with the printing surface have been devised. A heater is built into the squeegee and heated to a constant temperature to reduce the viscosity of the paste and improve the filling property. Further, since the viscosity of the paste increases in proportion to the operating time, the pastes are replaced at regular intervals or an organic solvent is added to stabilize the viscosity of the paste. In addition, in order to control the filling amount of the paste into the via hole and the through hole that have been processed with holes, the filling amount is stabilized by filling the paste up to the upper end position (substrate surface) of the hole.

Further, in the method of plating a conductor in a via hole or a through hole, wiring is not formed only on the outermost surface, but double-sided plates and prepregs are alternately laminated and integrated by heating / pressing. Further, a hole is formed at a desired position, and the inner surface of the hole is electrically plated by using the outermost copper foil. After that, holes are filled in so that the etching solution does not enter the through holes, and after that, a dry film is laminated on the surface, and the steps of exposure, development, etching, and dry film removal are completed until the completion.

A specific example of the above-described conventional method for manufacturing a circuit board will be described below with reference to FIGS.

FIG. 5A schematically shows a conventional method for manufacturing a laminated circuit board. In this figure, 50 is a double-sided plate, 5
1 is wiring formed on both sides of the double-sided plate 50, 52 is prepreg, 53 is copper foil, and 54 is a part (face) that is heated and pressed by a press machine.
A prepreg 52 and a copper foil 53 are arranged on both sides of the double-sided plate 5 and the double-sided plate 50 and the like are heated and pressed by a heating / pressing portion 54 at a predetermined temperature and a predetermined time for a predetermined time.
0, the prepreg 52, and the copper foil 53 are integrated.

FIG. 5B schematically shows a method of forming a hole in the laminated circuit board, where 55 is a drill and 56 is a hole formed by the drill 55. In this process,
The drill 55 descends from above the copper foil 53 while rotating,
A through hole is sequentially formed from the copper foil 53 by a cutting edge at the tip of the drill 55 to form a through hole.

FIGS. 6 (a) and 6 (b) schematically show a conventional paste filling process. 61 is a mask, 62 is a base material for supporting the mask 61, and 63 and 64 are on the mask 61. While moving squeegee, 65 is paste, 66
Is the stage. In this filling process, the stage 6
The base material 62 is placed in contact with the top surface of the base material 6. A mask 61 is arranged above the base material 62 with a slight space left therebetween, and the paste 65 can be supplied onto the mask 61. Squeegees 63 and 64 are arranged above the mask 61, and the squeegees 63 and 64 are movable in the vertical direction and the printing direction.

In this filling operation, first, the base material 62 is placed at a predetermined position on the stage 66. Next, the position of the through hole formed in the base material 62 and the position of the hole formed in the mask 61 are aligned, and the mask 61 is set on the base material 62. Next, the paste 65 is supplied onto the mask 61, the squeegees 63 and 64 are lowered, and the substrate 62 is held in a state where a predetermined pressure is applied. Further, printing is performed by moving the squeegees 63 and 64 in the printing direction and moving the paste 65 on the mask 61, and the paste 65 is pressed into the through holes of the base material 62 to be filled.

[0012]

By the way, when a method of transmitting light as a signal instead of an electric signal is selected,
The optical-electrical conversion element is arranged at a desired position, and the optical fiber is arranged on the substrate to transmit the signal. In this case, an optical information communication circuit such as an LD, a PD, an optical amplifier, and an optical switch exists in the information transmission path, so that in addition to the information transmission wiring, a metal wiring for electric signal transmission is separately required.
As a result, metal wiring must be provided in addition to the optical wiring, which causes a problem that the manufacturing process becomes complicated.

When another signal needs to be transmitted in addition to the optical signal, for example, when the destination of the optical signal has to be switched according to the routing information, a signal wiring for the routing information or the like is required separately, For the same reason, there arises a problem that the manufacturing process becomes complicated.

Further, in the information transmission by the optical signal, there is a problem that noise is generated by the disturbance light entering the optical wiring. Furthermore, since there is an optical wiring in which a current flows near the surface layer, there arises a problem that the insulation resistance between the optical wiring and the surface must be sufficiently high.

According to the present invention, in a circuit having at least one of an electro-optical converting means and an opto-electric converting means, a wiring pattern is formed by transmitting an optical signal and power or an optical signal and an electrical signal through the same wiring. An optical / electrical circuit that can be simplified and the manufacturing process can be simplified by reducing the number of wirings. Further, the present invention provides an optical / electrical wiring board capable of reducing noise due to ambient light and having sufficiently high insulation resistance between the optical wiring and the surface.

[0016]

In order to achieve such an object, in a circuit provided with an optical signal transmission path, the optical signal transmission path is made transparent to the optical signal and conductive. It is formed of a material having the above, and transmits an optical signal and electric power or an optical signal and an electric signal at the same time through the transmission path. Note that this material is ITO, ZnO, In
₂ 0 ₃ , SnO ₂ , ITO, AZO, ATO, FZO,
It can be selected from FIO and FTO.

The optical / electrical wiring board of the present invention is an optical / electrical wiring board having the above-mentioned optical / electrical circuit, and is for transmitting the optical signal and power or the optical signal and electric signal at the same time. The transmission line is formed by an optical waveguide, and the optical waveguide is embedded in an insulating substrate.

Further, an optical / electrical wiring board according to another embodiment of the present invention uses, as a material of the board, a material which absorbs or reflects light of a wavelength range used for transmitting the optical signal. is there.

[0019]

DETAILED DESCRIPTION OF THE INVENTION First Embodiment FIG. 1 shows an optical / electrical circuit 1 according to the first embodiment. This optical / electric circuit 1
Has three light emitting elements 2a, 2b, 2c. These 3
As the two light emitting elements 2a, 2b, 2c, those which emit lights of different wavelengths λ1, λ2, λ3 are used.
Each of the light emitting elements 2a, 2b, 2c has a power source 3a, 3b, 3c.
Are connected to the switches 4a, 4b, 4c, and the light emitting elements 2a, 2b, 2c can be individually turned on / off by turning on / off the switches 4a, 4b, 4c. The light emitting elements 2a, 2b, 2c also include a light guide path 5a,
Lights emitted from the light emitting elements 2a, 2b, and 2c are respectively connected to the light combiner 6 via the light guide elements 5a, 5b, and 5c and are collected and combined in the light combiner 6. Is done.

The circuit board 7 includes, in addition to the above-described photosynthesizer 6,
A channel type in which three photodiodes 8a, 8b, 8c and light emitted from the photo-combiner 6 are transmitted to the first photodiode 8a, then the second photodiode 8b, and then to the third photodiode 8c. The waveguide (transmission path) 9 is supported. First photodiode 8a
Is equipped with a first optical filter 10a at the connection with the waveguide 9. The first optical filter 10a has a function of selectively transmitting only the light of the first wavelength λ1. Similarly, the second photodiode 8b includes a second optical filter 10b at the connection portion with the waveguide 9. The second optical filter 10b has a function of selectively transmitting only the light of the second wavelength λ2.

Among the optical / electrical circuits 1 described above,
In particular, the waveguide 9 will be described in detail with reference to FIG. 2. The waveguide 9 is formed on the circuit board 7 by using, for example, a well-known etching technique as shown in FIG. It is covered by 11. Board 7
It is preferable to use a material that does not transmit the light of the wavelength used in the optical / electrical circuit 1. The material forming the waveguide 9 is
A material having not only translucency but also conductivity is used, and in particular, it is preferable to use a material having a sufficiently small loss with respect to the wiring length in the wavelength range of light used for signal transmission. For example, as a suitable material having translucency and conductivity, ITO, ZnO, In ₂ O ₃ , SnO ₂ , ITO,
There are AZO, ATO, FZO, FIO, FTO and the like. The cladding layer 11 is made of, for example, SiO ₂ .

Returning to FIG. 1, the first to third photodiodes 8a, 8b and 8c are connected to the corresponding light bulb lighting circuits 12a, 12b and 12c, respectively. The light bulb lighting circuits 12a, 12b, 12c respectively include the light bulbs 13a, 1
3b, 13c and switching transistors 14a, 14b, 14c serially connected thereto are provided, and are connected to a power supply 15 via a conductive waveguide 9. First
~ The third photodiodes 8a, 8b, 8c are also the bases of the transistors 14a, 14b, 14c and the power source 1 included in the corresponding light bulb lighting circuits 12a, 12b, 12c.
5 and is connected through the waveguide 9 to the wavelength λ1,
When light of λ2 and λ3 is incident, a predetermined current is applied to the bases of the corresponding transistors 14a, 14b, 14c.

In the optical / electrical circuit having such a structure, the light emitted from the three light emitting elements 2a, 2b, 2c (lights of wavelengths λ1, λ2, λ3) is corresponding to the light guide path 5.
It is transmitted to the optical combiner 6 via a, 5b, and 5c, and is combined there. The combined light is transmitted to the first to third photodiodes 8a, 8b, 8c through the waveguide 9, and the light having the first wavelength λ1 is transmitted by the first photodiode 8a in the transmission process. The detected light having the second wavelength λ2 is detected by the second photodiode 8b, and the light having the third wavelength λ3 is detected by the third photodiode 8c. Then, the photodiodes 8a, 8b, 8c that have detected the light are associated with the corresponding bulb lighting circuit 12
transistors 14a, 1 included in a, 12b, 12c
4b and 14c are turned on. As a result, the transistor 14
a, 14b, 14c through the light bulb 13a, 13b, 13
An electric current flows through c, and the light bulbs 13a, 13b, 13c are turned on.

As described above, according to the optical / electrical circuit of the first embodiment, the waveguide, which is a transmission path for transmitting light, functions as a transmission path for transmitting electric power to the light bulb and the photodiode. Therefore, since the electric power is also supplied to the electric bulb lighting circuit through the waveguide, it is not necessary to separately form a metal wiring for supplying electric power on the substrate. Therefore, the manufacture of the substrate is significantly simplified.

II. Second Embodiment: FIG. 3 shows an optical / electrical circuit 21 according to a second embodiment. The optical / electrical circuit 21 has one light emitting element 22. The light emitting element 22 is connected to a power source 23 and a switch 24, and the switch 24
By turning on and off, the light emitting element 22 can be turned on and off. On the other hand, the circuit board 25 includes two photodiodes 26 a, 2 in addition to the light emitting element 22 described above.
6b, the light emitting element 22 and the photodiode 26 at one end
It supports three channel type waveguides (transmission lines) 27, 28a and 28b which are respectively connected to a and 26b.
Further, the waveguides 27, 28a, 28b can be formed in the same manner as in the first embodiment, but as shown in FIG. 4, they are embedded in the substrate 25 to prevent disturbance light from entering the optical waveguide. To this end, the periphery is covered with the cladding layer 29. The materials forming the substrate 25, the waveguide, and the clad layer are the same as those in the first embodiment.

Returning to FIG. 3, the substrate 25 is provided with a movable mirror type optical path switching device 30. The switching device 30 includes a first waveguide 27, second and third waveguides (branch paths) 28a,
The other end of 28b is connected. The switching device 30 also includes a movable mirror 31, which is the first mirror.
The first position (solid line position) for guiding the light sent from the second waveguide 27 to the second waveguide 28a, and the light sent from the first waveguide 27 to the third waveguide 28b. The second position (dotted line position) can be moved. The movable mirror 31 moves between the first position and the second position according to the signal input to the switching device 30. Therefore, the switching device 30 uses the conductive waveguide 27 to
It is connected to a power source 32 and a switch 33. As shown in the figure, the movable mirror 31 is set to the first position with the switch 33 turned off, and the switch 33 is turned on to apply a predetermined voltage to the switching device 30. Then the movable mirror 31 becomes the second
The position can be switched to.

The photodiodes 26a and 26b are connected to the corresponding light bulb lighting circuits 34a and 34b, respectively. Each of the light bulb lighting circuits 34a and 34b includes light bulbs 35a and 35b, switching transistors 36a and 36b, and power supplies 37a and 37b connected in series. The photodiodes 26a and 26b also include the transistors 3 included in the corresponding light bulb lighting circuits 34a and 34b.
It is connected between the bases of 6a and 36b and the power sources 37a and 37b, and when light is incident through the waveguides 28a and 28b, a predetermined current is applied to the bases of the corresponding transistors 36a and 36b. It is configured.

In the optical / electrical circuit having such a structure, the light emitted from the light emitting element 22 is transmitted to the switching device 30 via the waveguide 27. Now, when the switch 33 is turned off and the movable mirror 31 is in the first position, the light emitted from the waveguide 27 is reflected by the movable mirror 31 and is reflected by the first mirror.
Is transmitted to the waveguide 28a. On the other hand, when the switch 33 is turned on and the movable mirror 31 is in the second position, the light emitted from the waveguide 27 is reflected by the movable mirror 31 and is reflected by the second mirror.
Is transmitted to the waveguide 28b. Waveguide 28a or 28b
The light emitted from the photodiode 26a or 26b
Detected in. The photodiode 26a or 26b that has detected the light applies a predetermined current to the base of the transistor 36a or 36b included in the corresponding light bulb lighting circuit 34a or 34b. As a result, a current flows through the light bulb 35a or 35b via the transistor 36a or 36b, and the light bulb 35a or 35b is turned on.

As described above, according to the optical / electrical circuit of the second embodiment, the waveguide, which is a transmission line for transmitting light, functions as a transmission line for transmitting an electric signal to the switching device. Therefore, it is not necessary to separately form a metal wiring for supplying an electric signal on the substrate. Therefore, the manufacture of the substrate is significantly simplified. In addition, since the substrate is formed of a material that does not transmit the light of the wavelength range used for optical signal transmission, it is possible to reduce noise caused by incident ambient light on the optical waveguide.

The optical / electrical circuit and the optical / electrical wiring board according to the present invention are not limited to the above-mentioned embodiments, and are equally applicable to circuits and boards which require wiring for transmitting light and electricity. .

[0031]

As described above, according to the present invention, since the transmission line having the light transmitting property also has the conductivity, it is possible to simultaneously transmit the optical signal and the electric power or the electric signal using this transmission line. it can. Therefore, it is not necessary to form the power supply wiring, and the manufacturing process is simplified. Further, by embedding the optical transmission line in the substrate, the insulation resistance between the optical wiring and the surface can be sufficiently increased. Further, by using a material that absorbs or reflects light in the wavelength range used for the transmission of an optical signal as the substrate material, it is possible to reduce noise caused by incident ambient light on the optical waveguide.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an optical / electrical circuit according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a cross-sectional structure of the optical waveguide used in the first embodiment.

FIG. 3 is a schematic diagram of an optical / electrical circuit according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram showing a cross-sectional structure of the optical waveguide used in the second embodiment.

FIG. 5 is a schematic view showing a conventional method for manufacturing a circuit board.

FIG. 6 is a schematic view showing a method and an apparatus for manufacturing a circuit board in a paste filling process of a conventional technique.

[Explanation of symbols]

1: Optical / electrical circuit 2a, 2b, 2c: light emitting element 7: Circuit board 8a, 8b, 8c: Photodiodes 9, 27, 28a, 28b: Waveguide 10a, 10b: Optical filter

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takafumi Okuma             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Kenichi Yamamoto             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Takaaki Higashida             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Munekazu Nishihara             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 2H047 KA04 KA05 LA09 LA18 MA07                       PA04 PA05 PA12 PA14 PA24                       QA04 RA08 TA05 TA41                 4E351 BB01 DD31 DD35 GG20                 5E338 AA03 BB80 CC01 CC10 CD12                       EE32

Claims (7)

[Claims] 1. A circuit provided with an optical signal transmission line,
The transmission path of the optical signal has a translucency for the optical signal,
An optical / electrical circuit, which is formed of a material having electrical conductivity. 2. The material is ITO, ZnO, In ₂ 0
₃ , SnO ₂ , ITO, AZO, ATO, FZO, FI
The optical / electrical circuit according to claim 1, comprising at least one selected from O and FTO. 3. The light according to claim 1, wherein electric power is transmitted through the transmission line.
electric circuit. 4. The optical / electrical circuit according to claim 1, wherein an electric signal is transmitted through the transmission line. 5. An optical / electrical wiring board having the optical / electrical circuit according to claim 3, wherein the transmission path for simultaneously transmitting the optical signal and the electric power is formed by an optical waveguide, An optical / electrical wiring board, in which an optical waveguide is embedded in an insulating board. 6. An optical / electrical wiring board having the optical / electrical circuit according to claim 4, wherein the transmission path for simultaneously transmitting the optical signal and the electrical signal is formed by an optical waveguide, An optical / electrical wiring substrate, wherein the optical waveguide is embedded in an insulating substrate. 7. The light according to claim 5, wherein a material that absorbs or reflects light having a wavelength used for transmitting the optical signal is used as a material of the substrate. -Electrical wiring board.