JP7488466B2 - Electric rice cooker - Google Patents

Description

This invention relates to an electric rice cooker configuration that has control units on both the lid and main body, allowing them to wirelessly transmit and receive information to and from each other.

Many recent electric rice cookers have a microcomputer board (display board) equipped with an operating switch, liquid crystal panel, and microcomputer unit on the lid side, and a control board (power supply board) on the main body side that controls the output of heating means such as a work coil or heater. These microcomputer boards and control boards are generally connected to each other using a flexible flat cable (FFC) to send and receive the necessary signals (for example, see the configurations of the electric rice cookers in Patent Documents 1 and 2).

Flexible flat cables are made by arranging multiple flat conductors horizontally inside an insulator, and can be easily made multi-core. They are also thin, making them highly flexible, and relatively easy to install in places with limited mounting space or on moving parts.

Therefore, it is suitable for connecting one end to the connector on the microcomputer board inside the lid, extending the other end rearward through the gap inside the lid, and introducing it into the main body through the gap between the back of the hinge part that supports the lid so that it can be opened and closed vertically at the rear of the lid and main body, and the hinge cover that covers the hinge part, and connecting the introduction end to the connector on the control board on the main body side.

However, flexible flat cables, which are flat conductors, extend a long distance from the microcomputer board on the cover side to the control board on the main body side via the hinge section, and there is a problem that various types of noise are picked up along the way (the hinge section, which is made up of a metal hinge axis and hinge coil, is particularly prone to becoming a noise source). This intruding noise can cause the microcomputer unit to malfunction and impair the reliability of the rice cooker's control functions. In addition, flexible flat cables themselves can be a source of noise radiation, so EMI countermeasures must be considered. For this reason, shielding measures such as installing noise filters in the connector section and attaching noise suppression sheets to the cable surface are also adopted, but these are not sufficient measures.

Furthermore, even though flexible flat cables are flexible, they are still made by sandwiching a thin flat conductor between insulators, and repeated local bending at the hinge unit at the rear end of the lid inevitably limits their durability. Patent documents 1 and 2 take some kind of measure to address this issue, but do not provide a fundamental solution. In the case of Patent document 2, the length of the flexible flat cable is increased, making it more susceptible to picking up and radiating noise.

To solve these problems, electric rice cookers have been proposed that use a photocoupler system to optically couple the lid and main body, enabling optical communication between them (see the configuration of an electric rice cooker in Patent Document 3). With this configuration, at least when the lid is closed and the lid and main body are optically coupled, optical signals can be transmitted and received between the microcomputer on the lid side and the microcomputer on the main body side, making it possible to do away with the flexible flat cable. Because the transmitting and receiving parts are optically coupled, they are not affected by electromagnetic noise and do not become a source of electromagnetic noise radiation. There is also no need to consider durability, and the lid can be opened and closed smoothly.

Furthermore, in the electric rice cooker of Patent Document 3, a power receiving unit is provided on the lid side and a power supply unit is provided on the main body side, and by coupling them in an electromagnetically inductive manner when the lid is closed, it is possible to supply power wirelessly from the main body to the lid side. This means that the power cable for power supply can also be eliminated, and the lid and main body are made completely wireless.

JP 2011-239903 A JP 2019-24951 A JP 2019-154651 A

However, in the case of Patent Document 3, both the optical coupling by a photocoupler for optical communication between the microcomputer on the lid side and the microcomputer on the main body side, and the electromagnetic coupling for supplying power from the power supply part on the main body side to the power receiving part on the lid side are realized on the condition that the lid is closed. If the lid is open, the coupled state is not realized, and neither communication nor power supply is possible.

Therefore, in the case of an electric rice cooker with the same configuration, for example, if you open the lid while the rice is in the warm state and try to cancel the warm state after serving the rice in the inner pot, you cannot cancel it as it is, and you have to close the lid once to return to the warm state and press the cancel key again, which is very inconvenient to use. For this reason, it cannot be applied to electric rice cookers that allow the operation keys to be operated even when the lid is open (see, for example, JP 2017-79833 A).

The present invention has been made to solve these problems, and aims to provide an electric rice cooker that has a light-emitting section and a light-receiving section that correspond to each other on the lid and the main body, and that optically connects the light-emitting section and the light-receiving section to each other via a flexible light guide, enabling optical communication, thereby enabling proper wireless transmission and reception regardless of whether the lid is open or closed, without being affected by electromagnetic noise or static electricity.

To achieve the above objective, the present invention is configured with the following problem-solving means:

(1) Solution to the Problems of the Invention of Claim 1 The solution to the problems of the invention of Claim 1 is an electric rice cooker comprising: a rice cooker body; a lid body that is pivotally supported on the rear end side of the opening of the rice cooker body via a hinge shaft so as to be openable and closable, and that covers the opening of the rice cooker body in a closed state; a first electric board having a first microcomputer provided on the inside of the lid body; and a second electric board having a second microcomputer provided on the inside of the rice cooker body, wherein a light emitting unit and a light receiving unit are provided on the first electric board having the first microcomputer and the second electric board having the second microcomputer, respectively, and the light emitting unit and the light receiving unit are connected to each other via a flexible light guiding body so as to be capable of optical communication ,
The flexible light guide that optically connects the light emitting section and the light receiving section of each of the first electrical board having the first microcomputer and the second electrical board having the second microcomputer is characterized in that it is arranged through the back side of the hinge axis .

In this way, when a light emitting section and a light receiving section are provided on each of the first electrical board having the first microcomputer on the lid side and the second electrical board having the second microcomputer on the main body side, and the light emitting section and the light receiving section are connected to each other via a flexible light conductor so that they can optically communicate with each other, the light emitting signal (transmission signal) from the light emitting section of the first electrical board having the first microcomputer on the lid side is reliably input (received) via the flexible light conductor to the light receiving section of the second electrical board having the second microcomputer on the main body side, and the light emitting signal (transmission signal) from the light emitting section of the second electrical board having the second microcomputer on the main body side is reliably input (received) via the flexible light conductor to the light receiving section of the first electrical board having the first microcomputer on the lid side.

This forms a two-way optical communication path between the first electrical board with the first microcomputer on the cover side and the second electrical board with the second microcomputer on the main body side, enabling transmission and reception in exactly the same way as with conventional flexible flat cables. Furthermore, this two-way optical communication path consisting of the light-emitting section, light-guiding body, and light-receiving section is an optical transmission path and is not affected by electromagnetic noise or static electricity at all, so there are no problems with malfunctions due to electromagnetic noise intrusion or electromagnetic noise radiation, as occurs with flexible flat cables. This reduces the design burden for EMI countermeasures for the entire device, EMC testing, etc. Furthermore, unlike harnesses made of electrical conductors, there is no energy loss due to electrical resistance, and power consumption is reduced.

In this case, the light emitting device of the light emitting section is, for example, a light emitting diode, the light receiving device of the light receiving section is, for example, a photodiode or a phototransistor, and the light is, for example, infrared (near infrared) or visible light. Light emitting diodes have a fast response speed to drive signals and are capable of high speed blinking. Therefore, they are suitable for driving with carrier pulses at a level of tens of thousands of times per second, as described below. The response speed of the photodiode or phototransistor of the light receiving section is also similar, and they can receive a blinking light signal transmitted with a similar carrier pulse and quickly perform photoelectric conversion.

In this case, the flexible light guide only requires a short transmission distance, and it only needs to transmit the light emitted from the light emitting section when the light is turned on to the light receiving section in a waveguide-like manner. Therefore, unlike a flexible flat cable that has a multi-core structure formed by sandwiching a thin flat conductor between insulators, a light guide with a simple structure and a specified optical path diameter that corresponds to the device size, light emission angle, and light reception angle (beam angle) of the light emitting section and light receiving section is sufficient.

As an example of such a light guide, for example, a light tube (light guide tube) or a light cable (light guide cable) is used. For the light tube used here, for example, a silicon rubber tube is used, which has a high cross-sectional deformation strength of the peripheral wall, and the cross-sectional shape does not change even when bent, but the tube as a whole has high flexibility and flexibility. As a result, when it is arranged behind the hinge part, it is hardly subjected to stress even if it comes into contact with the hinge axis of the hinge part, and durability is high. The inner surface of the silicon rubber tube is formed into a reflective surface with a high reflectivity that totally reflects infrared rays or visible light irradiated in the axial direction.

In this configuration, most of the light emitted by the light-emitting unit enters the optical transmission path (space inside the tube) from one end of the optical tube at a shallow entrance angle, and is efficiently transmitted to the light-receiving unit on the other end while being totally reflected by the inner reflective surface without interference. This increases the efficiency of light transmission from the light-emitting unit to the light-receiving unit, improving signal transmission and reception performance.

The optical cable may have a two-layered cable structure, consisting of a transparent core with a high refractive index and a clad with a low refractive index that covers the outer periphery of the core. In this configuration, most of the light emitted from the light-emitting section enters the core from one end of the cable at a shallow entrance angle, and is efficiently transmitted to the light-receiving section at the other end without interference, undergoing total reflection at the boundary between the core and clad. This results in high signal transmission and reception performance, similar to that of optical tubes.

In this case, too, by selecting a sufficiently flexible synthetic resin material for the core material and clad material, it is possible to easily construct a flexible light guide that can be flexibly bent in response to the opening and closing of the lid. As a result, when it is placed behind the hinge section, it is hardly subjected to stress even if it comes into contact with the hinge shaft of the hinge section, and durability is increased.

The problem-solving means of the present invention is characterized in that, based on the above-mentioned configuration, a flexible light guide that connects the light-emitting section and the light-receiving section of each of the first electrical board having the first microcomputer and the second electrical board having the second microcomputer so as to be capable of optical communication with each other is arranged through the back side of the hinge axis.

In this way, when a flexible light guide that connects the light emitting section and the light receiving section of each of the first electrical board having the first microcomputer and the second electrical board having the second microcomputer so as to enable optical communication with each other is arranged through the back side of the hinge axis, the optical tube is subjected to local bending deformation in a direction perpendicular to the axis at the hinge axis part in the middle, for example, by 90 degrees when the lid is closed and by 110 degrees when the lid is open, as in the case of conventional flexible cables.

However, the light guide has a simple tube structure as described above, and is flexible and strong, and does not have the problem of breakage that occurs with conventional flexible cables.

(2) Solution to the Problems of the Invention of Claim 2 The solution to the problems of the invention of claim 2 is an electric rice cooker comprising: a rice cooker body; a lid body that is pivotally supported on the rear end side of the opening of the rice cooker body via a hinge shaft so as to be openable and closable, and that covers the opening of the rice cooker body in the closed state; a first electric board having a first microcomputer provided on the inside of the lid body; and a second electric board having a second microcomputer provided on the inside of the rice cooker body, wherein a light emitting unit and a light receiving unit are provided on the first electric board having the first microcomputer and the second electric board having the second microcomputer, respectively, and the light emitting unit and the light receiving unit are connected to each other via a flexible light guiding body so as to be capable of optical communication,
The hinge shaft has a hollow pipe structure, and flexible light guides that optically connect the light emitting section and the light receiving section of each of the first electrical board having the first microcomputer and the second electrical board having the second microcomputer are each disposed so as to penetrate the inside of the hinge shaft having the hollow pipe structure from one end to the other end .

In this way, when a light emitting section and a light receiving section are provided on each of the first electrical board having the first microcomputer on the lid side and the second electrical board having the second microcomputer on the main body side, and the light emitting section and the light receiving section are connected to each other via a flexible light conductor so that they can optically communicate with each other, the light emitting signal (transmitted signal) from the light emitting section of the first electrical board having the first microcomputer on the lid side is reliably input (received) to the light receiving section of the second electrical board having the second microcomputer on the main body side via the flexible light conductor, and the light emitting signal (transmitted signal) from the light emitting section of the second electrical board having the second microcomputer on the main body side is reliably input (received) to the light receiving section of the first electrical board having the first microcomputer on the lid side, also via the flexible light conductor.

As a result, a bidirectional optical communication path is formed between the first electric board having the first microcomputer on the cover side and the second electric board having the second microcomputer on the main body side, enabling transmission and reception in exactly the same way as with a conventional flexible flat cable. Moreover, this bidirectional optical communication path consisting of the light emitting section, light guiding body, and light receiving section is an optical transmission path and is not affected by electromagnetic noise or static electricity at all, so there are no problems with malfunctions due to electromagnetic noise intrusion or electromagnetic noise radiation as occurs with flexible flat cables. Therefore, it is possible to reduce the design burden of EMI countermeasures for the entire device, EMC tests, etc. Also, unlike harnesses made of electrical conductors, there is no energy loss due to electrical resistance, and power consumption is reduced.

In this case, the light emitting device of the light emitting section is, for example, a light emitting diode, the light receiving device of the light receiving section is, for example, a photodiode or a phototransistor, and the light is, for example, infrared (near infrared) or visible light. Light emitting diodes have a fast response speed to a drive signal and can blink at high speed. Therefore, they are suitable for driving with carrier pulses at a level of tens of thousands of times per second as described below. The response speed of the photodiode or phototransistor of the light receiving section is also similar, and they can receive a blinking light signal transmitted by a similar carrier pulse and quickly perform photoelectric conversion.

In this case, the flexible light guide only requires a short transmission distance, and it only needs to transmit the light emitted from the light emitting section when the light is turned on to the light receiving section in a waveguide-like manner. Therefore, unlike a flexible flat cable in which a flat, thin conductor is sandwiched between insulators to form a multi-core structure, a light guide with a simple structure and a specified optical path diameter corresponding to the device size, light emission angle, and light reception angle (beam angle) of the light emitting section and light receiving section will suffice.

As an example of such a light guide, for example, a light tube (light guide tube) or a light cable (light guide cable) is used. For the light tube used here, for example, a silicon rubber tube is used, whose peripheral wall has high cross-sectional deformation strength and does not change its cross-sectional shape even when bent, but whose entire tube has high flexibility and flexibility. As a result, when the silicon rubber tube is disposed behind the hinge part, even if it comes into contact with the hinge shaft of the hinge part, it is hardly subjected to stress, and durability is high. The inner peripheral surface of the silicon rubber tube is formed into a reflective surface with high reflectivity that totally reflects infrared rays or visible light irradiated in the axial direction.

In this configuration, most of the light emitted by the light emitting section enters the optical transmission path (space inside the tube) from one end of the optical tube at a shallow entrance angle, and is efficiently transmitted to the light receiving section at the other end while being totally reflected by the inner reflective surface without interference. Therefore, the transmission efficiency of light from the light emitting section to the light receiving section is improved, and the signal transmission and reception performance is improved.

In addition, the optical cable may have a two-layer structure consisting of a transparent core with a high refractive index and a clad with a low refractive index that covers the outer periphery of the core. In this type of structure, most of the light emitted from the light emitting section enters the core from one end of the cable at a shallow entrance angle, and is efficiently transmitted to the light receiving section at the other end without interference while being totally reflected at the boundary between the core and clad. Therefore, the signal transmission and reception performance is improved, similar to the case of the optical tube.

Also in this case, by selecting a synthetic resin material having sufficient flexibility for the core material and cladding material, it is possible to easily form a flexible light guide that can be flexibly bent in response to the opening and closing of the lid.

The problem-solving means of the present invention is based on the above configuration and is further characterized in that the hinge shaft has a hollow pipe structure, and a flexible light guide that connects the light-emitting section and the light-receiving section of each of the first electrical board having the first microcomputer and the second electrical board having the second microcomputer so that they can optically communicate with each other is disposed penetrating the inside of the hinge shaft having the hollow pipe structure from one end to the other end .

As in the problem-solving means of the invention of claim 1 above , a flexible light guide that connects the light-emitting section and the light-receiving section of each of the first electrical board having the first microcomputer and the second electrical board having the second microcomputer so that they can optically communicate with each other can also be arranged through the back side of the hinge axis.

However, if you do this, local bending deformation will occur repeatedly at the hinge axis in the middle, for example 90 degrees when the lid is closed, and 110 degrees when the lid is open, in a direction perpendicular to the axis. Therefore, even though the tube structure is simple and strong, some degree of fatigue and cross-sectional deformation will occur.

In contrast, if the hinge shaft is made of a hollow pipe structure and a flexible light guide is arranged penetrating the inside of the hinge shaft from one end to the other end of the hollow pipe structure, local bending deformation in the direction perpendicular to the axis is eliminated, and fatigue and cross-sectional deformation are effectively reduced. Of course, some deformation in the axial torsional direction occurs in the tube part of the hinge shaft when the lid is opened and closed, but the length of the penetrating part of the hinge shaft is long enough in both directions to absorb the amount of deformation and prevent local deformation. Therefore, fatigue and cross-sectional deformation become almost unnecessary.

As a result of the above, the electric rice cooker of the present invention reliably eliminates the risk of electromagnetic noise entering the control unit from the electrical wiring material composed of a wire harness such as a conventional flexible flat cable, the radiation of electromagnetic noise from the electrical wiring material to the outside, and the risk of disconnection when the lid is opened and closed, greatly improving the reliability of the rice cooker's control performance.

Also, unlike the photocoupler method, bidirectional communication and control are possible regardless of whether the lid is open or closed. Furthermore, the increased communication speed achieved by optical communication can greatly improve the responsiveness of rice cooker control, resulting in a more highly functional electric rice cooker.

In addition, because the microcomputers on the lid and main body have optical communication capabilities, it is also easy to install IoT-related peripheral devices that enable optical communication with the outside world around the electrical boards on the lid and main body, making the device even more multifunctional.

In addition, the realization of a wireless communication line with no electrical resistance, known as optical communication, also reduces power consumption, wiring costs, and connection work costs.

Furthermore, if a magnetic resonance type wireless power transmission device using an LC circuit is installed in the transmitting and receiving device, a completely wireless state (harness loss state) can be achieved between the lid and the main body, completely eliminating the need to connect the harness, significantly facilitating assembly work during manufacturing.

As a result, there will be no risk of damage to the circuit board due to incorrect power cable connection.

1 is a plan view showing a configuration of a rice cooker body of an electric rice cooker according to a first embodiment of the invention of this application. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, showing the internal configuration of the rice cooker body of the electric rice cooker. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, showing the internal structure of the rice cooker body of the electric rice cooker in the lid-open state. 4 is an enlarged cross-sectional view showing the configuration of a main part of the rice cooker body of the electric rice cooker (the configuration of the part surrounded by the imaginary line in FIG. 3 ). FIG. 2 is a block diagram showing an outline of the configurations of the microcomputer board circuit on the lid side and the control board circuit on the rice cooker body side in the electric rice cooker, and the relationship of their mutual connections. FIG. This is a schematic diagram showing the configuration of a first optical transmitting/receiving means for transmitting coded information from the main microcomputer unit on the microcomputer board on the lid body side to the sub-microcomputer unit on the control board on the rice cooker body side in the electric rice cooker. 13 is a schematic diagram showing the configuration of a second optical transmitting/receiving means for transmitting coded information from the sub-microcomputer unit on the control board on the rice cooker body side to the main microcomputer unit on the microcomputer board on the lid body side in the electric rice cooker. FIG. This is an oblique view showing the configuration of the light guide (light tube) in the transmitting/receiving means part that transmits coded information from the main microcomputer unit of the microcomputer board on the lid side of the electric rice cooker to the sub-microcomputer unit of the control board on the rice cooker body side, and from the sub-microcomputer unit of the control board on the rice cooker body side to the main microcomputer unit of the microcomputer board on the lid side. 9 is an end view showing the configuration of the light guide (light tube) of FIG. 8 in the electric rice cooker. FIG. 9 is a perspective view showing the light guiding effect of the light guide (light tube) of FIG. 8 in the electric rice cooker. FIG. This is a schematic diagram showing the circuit configuration of the first optical transceiver means that transmits coded information from the main microcomputer unit on the microcomputer board on the lid side to the sub-microcomputer unit on the control board on the rice cooker body side in the electric rice cooker. This is a schematic diagram showing the circuit configuration of the second optical transmitting/receiving means that transmits coded information from the sub-microcomputer unit on the control board on the rice cooker body side to the main microcomputer unit on the microcomputer board on the lid body side in the electric rice cooker. 12A and 12B are diagrams showing the waveforms of (a) coded information (commands and various data) to be transmitted, (b) carrier pulses for transmission, and (c) modulated pulses to be transmitted, which are used in the first optical transmission/reception means of FIG. 11 and the second optical transmission/reception means of FIG. 12 in the electric rice cooker. 14 is a partially enlarged view showing the relationship between the period T of the square pulse in the modulated pulse transmitted in FIG. 13( c) and the blinking period T/2 of the light emitting portion of the electric rice cooker. FIG. 9 is a cross-sectional end view showing the configuration of a composite light tube according to a modified example in which a plurality of light guides (light tubes) of FIG. 8 in the electric rice cooker are integrated in parallel. FIG. 13 is a rear view showing the arrangement structure of a light guide (light tube) in a hinge unit of a rice cooker body of an electric rice cooker according to a second embodiment of the present invention in a lid-open state. FIG. 4 is an enlarged cross-sectional view of a main portion showing an arrangement structure of a light guide (light tube) in a hinge unit of a rice cooker body of the electric rice cooker. FIG. This is an oblique view showing the configuration of a light guide (optical cable) in the transmitting/receiving means part that transmits coded information from the main microcomputer unit of the microcomputer board on the lid side in an electric rice cooker according to the third embodiment of the invention of this application to the sub-microcomputer unit of the control board on the rice cooker body side, and from the sub-microcomputer unit of the control board on the rice cooker body side to the main microcomputer unit of the microcomputer board on the lid side. FIG. 20 is an explanatory perspective view showing the light guiding effect of the light guide (optical cable) of FIG. 18 in the electric rice cooker. 19 is a cross-sectional end view showing the configuration of a composite optical cable according to a modified example in which a plurality of light guides (optical cables) of FIG. 18 are integrated in parallel in the electric rice cooker. FIG. A block diagram showing an outline of the configurations of the lid side microcomputer board circuit and the rice cooker body side control board circuit in an electric rice cooker according to a fourth embodiment of the invention of this application, and their mutual connection relationship. FIG. 2 is a block diagram showing the configuration of a wireless power transmission system in the electric rice cooker.

The configurations and operations of the first to fourth embodiments for implementing the invention of this application will be described in detail below with reference to the attached Figures 1 to 22.

<Configuration of electric rice cooker according to the first embodiment>
First, Figures 1 to 4 show the configuration of the rice cooker body and each part of the lid of an electric rice cooker equipped with an openable and closable lid according to the first embodiment of the invention of this application, and Figure 5 shows the configuration of the control circuit part on the lid side and on the rice cooker body side of the same electric rice cooker.

That is, the electric rice cooker according to the first embodiment of the invention of this application is configured, for example, as shown in Figures 1 to 5, and its basic components are an electric rice cooker main body 1, a lid body 2 that is pivotally supported on one end side of the opening of the electric rice cooker main body 1 and covers the opening of the electric rice cooker main body 1 in an openable and closable manner, a microcomputer board (display board) 50 that is a first electric board provided on the inside of the lid body 2, a control board (power supply board) 60 that is a second electric board provided on the inside of the electric rice cooker main body 1, and the first electric board. The cover 2 is configured with a first light guide 71 that optically connects the first light emitter 52 on the microcomputer board 50 side and the first light receiver 61 on the control board 60 side, which is the second electric board, through the rear end outer surface side of the hinge unit 9, which is the pivotal support part of the cover 2, and a second light guide 72 that optically connects the second light emitter 64 on the control board 60 side, which is the second electric board, and the second light receiver 53 on the microcomputer board 50 side, which is the first electric board, through the rear end outer surface side of the hinge unit 9, which is the pivotal support part of the cover 2.

That is, first, as shown in Figures 1 and 2, the electric rice cooker main body 1 (hereinafter simply referred to as the rice cooker main body) is composed of an inner pot 3 made of metal that can be heated by electromagnetic induction and that contains rice and water, an inner case (protective frame) 4 that is formed so that the inner pot 3 can be stored and set as desired, a coil stand 6 that is attached to the bottom side of the inner case 4 via an electromagnetic induction coil 5, a bottomed cylindrical outer case 7 that is an external housing that holds the coil stand 6 and the inner case 4, and a shoulder member 8 that connects and integrates the upper end of the outer case 7 and the upper end of the inner case 4. A lid 2 that covers the upper opening of the rice cooker main body 1 in an openable and closable manner is attached to the rear end of the shoulder member 8 via a hinge unit 9 that is a pivot support part so that it can be rotated relative to the rear end of the shoulder member 8, and is attached so that it can be opened and closed freely in the vertical direction.

The upper opening of the rice cooker body 1 is surrounded by the shoulder member 8, and the bottom wall 3a of the inner pot 3 is placed on the bottom wall 4a of the inner case 4. A center sensor insertion hole 4b is provided in the center of the bottom wall 4a of the inner case 4, and a center sensor (bottom sensor) 10 is placed from below through the center sensor insertion hole 4b so as to abut against the bottom wall 3a of the inner pot 3, thereby detecting the temperature of the inner pot 3 (the temperature of the rice).

A heater (body heater) 11, for example, that functions as a heating means during cooking and keeping warm is provided on the outer peripheral surface of the upper side of the inner case 4, and is designed to effectively and uniformly heat the side wall portion 3b of the inner pot 3 during cooking and keeping warm.

On the other hand, reference numeral 12 denotes a bottom case that closes the bottom opening of the outer case 7. An air intake grill 12a is provided at a certain width portion at the rear end of the bottom case 12 to take in cooling air into the rice cooker body, and a space for storing electrical equipment is formed above it. In this electrical equipment storage space, a control board (power supply board) 60, which is a second electrical board equipped with a work coil drive circuit including an IGBT that drives and controls the work coil 5, a heat retention heater drive circuit that drives and controls the heat retention heater 11, a rectifier circuit consisting of a diode bridge for rectifying the power supply voltage, a smoothing circuit, other electronic components 67, and heat dissipation fins 68 for cooling the IGBTs, is provided via a control board cover 66.

As shown in detail in FIG. 5 described later, the control board 60 is provided with a pair of a first light receiving unit 61 located on the upper left side thereof, which receives, via a first light conductor 71, the coded information (commands and control data) from the first light emitting unit 52 pulse-modulated by the main microcomputer unit 40A on the microcomputer board 50 side and performs photoelectric conversion, and a second light emitting unit 64 which photoelectrically converts the coded information (commands and control data) pulse-modulated by the sub-microcomputer unit 40B on the control board 60 side and transmits it to the second light receiving unit 53 on the microcomputer board 50 side via a second light conductor 72.

Between the control board cover 66 and the outer case 7 of the rice cooker main body 1, a cord reel installation space is formed that extends straight up and down (to the installation position of the hinge part of the shoulder member 8) as shown in Figures 1 and 2, and the cord reel 69 is provided at the center to the lower end.

Next, we will explain in detail the structure of the lid 2 that closes the upper opening of the rice cooker main body 1.

That is, as shown in Figs. 1 and 2, the lid body 2 is composed of an upper plate (main body cover) 21 made of synthetic resin that constitutes the upper main body surface, a lower plate (poly cover) 22 made of synthetic resin that is provided on the inside (lower side) of the upper plate 21, a metal heat sink 24 having a lid heater 23 that is polymerically fixed to the inside (lower side) of the main body part of the lower plate 22, and a metal inner lid 27 that is provided below the heat sink 24 and detachably attached to the lower plate 22 via a synthetic resin frame member 26 that has a rubber packing 25 on its outer periphery.

A synthetic resin nameplate 20 having a predetermined thickness, for example as shown in Figs. 1 and 2, is polymerized and integrated with the upper side of the top plate 21 of the lid body 2, and the front half of the nameplate 20 is provided with a hook button (lid opening/closing button) 20a, various operation switches 20b, 20c, 20d, 20e, 20f, 20g for timer, cooking, cancel, time, keep warm, menu, etc., and a liquid crystal display unit (its display surface) 20h. The hook button (lid opening button) 20a is supported so that it can be raised and lowered in the vertical direction, with its upper end operation surface facing the hook button installation hole provided in the top plate 21 from below.

In addition, the upper plate 21 of the lid body 2 is provided with an electrical equipment storage box 28 of a predetermined depth that is located below the various operation switches 20b, 20c, 20d, 20e, 20f, 20g such as the reservation, cooking, cancellation, time, keep warm, menu, etc., and the liquid crystal display unit (its display surface) 20h, and stores the various operation switches 20b, 20c, 20d, 20e, 20f, 20g such as reservation, cooking, cancellation, time, keep warm, menu, etc., the liquid crystal display unit 20h, and the microcomputer board 50, which is the first electrical board on which the main microcomputer (40A in FIG. 5) described later is mounted, and the various operation switches 20b, 20c, 20d, 20e, 20f, 20g, the liquid crystal display unit 20h (liquid crystal panel 20i), and the microcomputer board 50, which is the first electrical board on which the main microcomputer (40A in FIG. 5) described later is mounted, are stored in the electrical equipment storage box 28.

As shown in detail in FIG. 5 described later, the microcomputer board 50 is provided with a pair of a first light emitter 52 located on the left side of the rear end thereof, which photoelectrically converts coded information (commands and control data) pulse-modulated by the main microcomputer unit 40A on the microcomputer board 50 and transmits it to the first light receiver 61 on the control board 60 via the first light conductor 71, and a second light receiver 53 which photoelectrically converts and receives coded information (commands and control data) pulse-modulated by the sub-microcomputer unit 40B transmitted from the second light emitter 64 on the control board 60 via the second light conductor 72.

An inlet is provided on the left side of the rear wall of the electrical equipment storage box 28 to introduce the transmitting end of the first light guide 71 and the receiving end of the second light guide 72 to the first light emitter 52 and second light receiver 53 of the microcomputer board 50 (not shown).

The rear side of the lid 2 is provided with a steam cap storage groove that is roughly rectangular in plan view and has a relatively large area. The steam cap storage groove is provided with a steam cap 31 that is equipped with a steam hole that releases only steam to the outside while recovering sticky ingredients and adjusts the pressure inside the inner pot 3 during the rice cooking process. The symbol 31a is a steam release port of the steam cap 31, and a steam sensor 32 is provided in the steam hole upstream of the steam release port.

The hinge unit 9 that attaches the lid 2 to the rice cooker body 1 is a pivotal support that supports the rear end of the top plate 21 of the lid 2 so that it can rotate up and down, as shown in detail in Figures 2 and 3, and is composed of a hinge shaft 9a and a pair of left and right hinge shaft support members (not shown). A hinge coil 9b that urges the lid 2 to rotate in the opening direction is wound around the outer periphery of the hinge shaft 9a.

The hinge shaft 9a and the hinge shaft support member are fixed on the hinge unit installation portion provided on a predetermined width portion on the inner periphery of the rear end of the shoulder member (shoulder member main body) 8. In this state, a hinge cover (rear cover) 14 is provided integrally with the outer case 7 on the rear side of the hinge shaft 9a and the hinge shaft support member. This hinge cover 14 extends from the lower end of the hinge unit installation portion to the upper position of the hinge shaft 9a and the hinge coil 9b, and its upper end side is bent forward a predetermined distance to cover the upper part of the hinge coil 9b to form a curved surface. The space between the hinge shaft 9a and the hinge shaft 9a on the inside of this curved surface is configured to be a smooth arc-shaped guide space (freely deformable space) for the first and second light guide bodies 71 and 72 described above.

The first and second light guides 71, 72 are hollow optical tubes (light guide tubes) of a predetermined diameter with an optical transmission path 70 formed inside, as shown in Figures 8 and 9, and their inner peripheral surface is formed into a reflective surface 70a that totally reflects infrared rays. For example, a silicone rubber tube is used for this hollow optical tube, whose peripheral wall has high cross-sectional deformation strength and does not change its cross-sectional shape even when bent, but has high flexibility and flexibility as a whole. The first and second light guides 71, 72 made of such highly flexible and malleable optical tubes optically connect the first light emitter 52 and second light receiver 53 of the microcomputer board 50 to the first light receiver 61 and second light emitter 64 of the control board 60, as shown in Figures 1 and 2, for example. The tube body portions of the first and second light guides 71, 72 extending rearward from the first light emitter 52 and second light receiver 53 portions of the microcomputer board 50 pass between the upper plate 21 and lower plate 22 made of synthetic resin of the cover 2, bend gently downward behind the hinge axis 9a of the hinge unit 9, pass through the space between the shoulder member 8 and the hinge cover 14, and gently wrap around the lower side of the shoulder member 8, to be optically connected to the first light receiver 61 and second light emitter 64 of the control board 60. The connection ends between the first light emitter 52 and the second light receiver 53 on the microcomputer board 50 side, and the connection ends between the first light receiver 61 and the second light emitter 64 on the control board 60 side, as well as several points along the way, are fixed with fixing members 75, 75..., 75, 75... and are held in a stable state.

However, the rear part of the hinge shaft 9a is not fixed anywhere in particular and is free, so that even when the cover 2 is closed as shown in FIG. 2, it can bend gently downward while maintaining a specified gap so as not to come into contact with the rear side of the hinge shaft 9a, and the lower side of the shoulder member 8 is also smoothly connected and fixed to the first light receiving unit 61 and the second light emitting unit 64 on the control board 60 without interfering with the lower corner portion 8a of the shoulder member 8.

When the lid 2 is open, it bends gently in an S-shape behind the hinge shaft 9a, as shown in Figures 3 and 4, and no localized bends are generated. Even in this case, there is no interference with the hinge shaft 9a, hinge coil 9b, or the lower end corner portion 8a of the shoulder member 8.

In this embodiment, the dimension a between the shoulder member 8 and the hinge cover 14 and the dimension b between the hinge shaft 9a and the upper end of the control board cover 66 are sufficient. The first light guide 71 and the second light guide 72 are optical tubes made of silicone rubber and have sufficient flexibility and pliability, so even if they interfere with the hinge shaft 9a, the hinge coil 9b, or the lower end corner portion 8a of the shoulder member 8 for some reason, they will hardly deform or be damaged. However, in order to ensure a reliable transmission form that is less susceptible to interference with optical signals, it is better for the deformation part to be as gentle as possible. In addition, this also provides higher durability against opening and closing operations. For this reason, in this embodiment, the cover 2 is configured to be in a deformation state as gentle as possible whether it is in a closed state or an open state.

Next, we will explain the details of the circuit configurations of the microcomputer board 50 on the lid 2 side and the control board 60 on the rice cooker main body 1 side, and the details of their mutual connection structure. Figure 5 shows the details of the circuit configurations of the microcomputer board 50 on the lid 2 side and the control board 60 on the rice cooker main body 1 side, and the details of their mutual connection structure.

First, the microcomputer board 50 on the lid body 2 side is controlled by a main microcomputer unit 40A for controlling the operation switches 20b to 20g, the liquid crystal panel 20i, the lid heater 23, etc., the operation switches 20b to 20g, the liquid crystal panel 20i, a lid heater drive circuit 43 controlled by the main microcomputer unit 40A and driving the lid heater 23, a control power supply circuit 37 supplied with AC power from the AC power supply circuit 33 on the control board 60 via a power cable 36, a rechargeable battery 38 supplied with a predetermined charging current rectified by the control power supply circuit 37, and the main microcomputer unit 40A. It is configured with a first light-emitting unit driving means 51, a first light-emitting unit 52 that is driven ON/OFF by the first light-emitting unit driving means 51 and inputs the light emitted when ON to a first light-receiving unit 61 on the control board 60 side via a first light guide 71, a second light-receiving unit 53 that receives and demodulates an optical signal (an optical signal modulated according to commands and control data) transmitted from a second light-emitting unit 64 on the control board 60 side via a second light guide 72, and a second encoder (encoding unit) 54 that encodes the output of the second light-receiving unit 53 and inputs it to the main microcomputer unit 40A.

Operation switches 20b-20g are, for example, touch switches, and their respective operation states are input to the main microcomputer unit 40A. The liquid crystal panel 20i is controlled by the main microcomputer unit 40A to display the operation states of operation switches 20b-20g and the rice cooking and warming states based on the operation input. A steam detection signal is input to the main microcomputer unit 40A from a steam sensor 32 installed midway through the steam passage of the lid body 2. The lid heater drive circuit 43 is operated and controlled by the main microcomputer unit 40A to heat and drive the lid heater 23 installed on the heat sink 24 of the lid body 2.

In this embodiment, the main microcomputer unit 40A incorporates, for example, a low power detection circuit, an oscillator, an EEPROM, a reset IC, a temperature sensor (room temperature sensor), a multi-power interface port, etc. Therefore, there is no need to provide a low power detection circuit, an oscillator, an EEPROM, a reset IC, a temperature sensor (room temperature sensor), a multi-power interface port, etc., around the main microcomputer unit 40A as in the conventional case, and the microcomputer board 50 itself is miniaturized and the wiring is simplified.

Next, the control board 60 includes a sub-microcomputer unit 40B for controlling the drive of the work coil 5, the heat retention heater 11, the fan 17, etc., a work coil drive circuit 41 for driving the work coil 5, a heat retention heater drive circuit 42 for driving the heat retention heater 11, a fan drive circuit 44 for driving the fan 17, an AC power supply circuit 33 to which AC power is supplied from the outside via a power cord, a control power supply circuit 34 for rectifying and smoothing the power of the AC power supply circuit 33 to provide the necessary control power for the sub-microcomputer unit 40B, etc., and a first light guiding circuit 52 on the first light emitting part 52 on the microcomputer board 50 side. The sub-microcomputer unit 40B is made up of a first light receiving unit 61 that receives and demodulates the optical signal (optical signal modulated according to commands and control data) transmitted through the body 71, a first encoder (encoding unit) 62 that encodes the output of the first light receiving unit 61 and inputs it to the sub-microcomputer unit 40B, a second light emitting unit driving means 63 controlled by the sub-microcomputer unit 40B, and a second light emitting unit 64 that is driven ON/OFF by the second light emitting unit driving means 63 and inputs the light emitted when ON through the second light guiding body 72 to the second light receiving unit on the microcomputer board 50 side. An inner pot temperature detection signal is input to the sub-microcomputer unit 40B from the center sensor 10 that detects the temperature of the inner pot 3.

The first light-emitting unit driving means 51 and the first light-emitting unit 52 on the microcomputer board 50, the first light guide 71 that optically connects the first light-emitting unit 52 on the microcomputer board 50 to the first light-receiving unit 61 on the control board 60, and the first light-receiving unit 61 and the first encoder 62 on the control board 60 form a first optical transmission means that optically transmits control signals (commands and control data) required for control from the main microcomputer unit 40A to the sub-microcomputer unit 40B.

The second light-emitting unit driving means 63 and the second light-emitting unit 64 on the control board 60 side, the second light-guiding body 72 that optically connects the second light-emitting unit 64 on the control board 60 side and the second light-receiving unit 53 on the microcomputer board 50 side, and the second light-receiving unit 53 and the second encoder 54 on the microcomputer board 50 side form a second optical transmission means that optically transmits control signals (commands and control data) required for control from the sub-microcomputer unit 40B to the main microcomputer unit 40A.

In other words, the main microcomputer unit 40A and the sub-microcomputer unit 40B are connected to each other so that they can transmit and receive signals bidirectionally via these first and second optical transmission means.

The first light-emitting unit driving means 51 and the first light-emitting unit 52 on the microcomputer board 50, the first light guide 71 optically connecting the first light-emitting unit 52 on the microcomputer board 50 and the first light-receiving unit 61 on the control board 60, and the first light-receiving unit 61 and the first encoder 62 on the control board 60 are configured, for example, as shown in Figures 6 and 11.

That is, as shown in FIG. 6, the first light emitter 52 on the microcomputer board 50 side is configured with, for example, a first infrared light emitting diode 52a, while the first light receiver 61 on the control board 60 side is configured with a first photodiode 61a, and the first infrared light emitting diode 52a and the first photodiode 61a are connected to each other in a state where they form an optical transmission path by the first light guide 71.

The first light guide 71 is a hollow optical tube of a predetermined diameter with an optical transmission path 70 formed inside as shown in Figures 8 and 9, and its inner peripheral surface is formed into a reflective surface 70a that totally reflects infrared light. The first light guide 71 of the same configuration is connected at both ends to the spherical lens portions of the first infrared light emitting diode 52a and the first photodiode 61a so that no light leaks.

In this configuration, the infrared light emitted in the axial direction from the first infrared light emitting diode 52a enters the transmission path 70 at a shallow angle of incidence from one end of the first light guide 71 made of the optical tube, as shown in FIG. 10, and is efficiently transmitted to the first photodiode 61a without interference while being totally reflected by the reflecting surface 70a. Of course, there is no intrusion of external electromagnetic noise during this time, and no radiation of electromagnetic noise to the outside.

In this case, the light tube is made of, for example, silicone rubber and has a sufficiently flexible tube structure, and is configured as a pliable light guide 71 that can be flexibly bent in response to the opening and closing of the lid 2. As a result, when the light tube is arranged behind the hinge unit 9 as described above, even if it comes into contact with the hinge shaft 9a or hinge coil 9b, it is hardly subjected to stress and has high durability.

More specifically, the first light-emitting unit 52 and the first light-receiving unit 61 shown in FIG. 6 are configured as shown in FIG. 11.

That is, when optical communication is performed between the main microcomputer 40A and the sub-microcomputer 40B described above, it is necessary to superimpose coded information such as commands and various data to be transmitted onto a specified carrier wave. A square pulse wave is generally used as the carrier wave, and methods for superimposing coded information onto the same pulse wave include pulse width modulation (PWM), in which the H (high) time of the carrier pulse on the time axis changes depending on the input signal (coded information), and pulse position modulation (PPM), in which the position of the carrier pulse on the time axis changes depending on the input signal (coded information).

This embodiment is configured using pulse position modulation (PPM), in which the position of the carrier pulse on the time axis changes depending on the input signal (encoded information). Pulse position modulation (PPM) can change the number of slots depending on the number of bits sent at one time, and assigns information depending on which slot the pulse is in (whether the slot is ON). For example, when configured as a binary digital communication means, two slots are prepared, and if the first slot is H (high), it indicates information [0], and if the second slot is H (high), it indicates information [1]. And if four slots are prepared, it becomes a four-value PPM, and four types of information can be sent with one symbol.

The carrier pulse used here is a square carrier pulse (FIG. 13(b)) that drives the first infrared light emitting diode 52a of the first light emitting unit 52 to blink at least tens of thousands of times per second, and is formed by the main microcomputer unit 40A functioning as a transmission control means. The carrier pulse (FIG. 13(b)) formed by the main microcomputer 40A is pulse position modulated according to the coded information to be transmitted (FIG. 13(a)), and the first infrared light emitting diode 52a of the first light emitting unit 52 is driven to blink based on the modulated carrier pulse (FIG. 13(c)), which is then transmitted to the first photodiode 61a of the first light receiving unit 61 as a digital optical signal. FIG. 14 shows the relationship between the blinking time of the light emitting diode 52a in the modulated carrier pulse (FIG. 13(c)) and the period T.

The first light-emitting unit driving means 51, which drives the first infrared light-emitting diode 52a of the first light-emitting unit 52 to blink, is composed of a switching transistor, for example, as shown in FIG. 11, and is controlled to be turned on and off by the modulated pulse shown in FIG. 13(c) supplied from the main microcomputer unit 40A, which is the transmission control means. The first infrared light-emitting diode 52a lights up and emits infrared light when the switching transistor is ON.

Meanwhile, in the same state, the sub-microcomputer unit 40B on the control board 60 side functions as a receiving control means, and receives the digital optical signal transmitted from the first infrared light emitting diode 52a of the first light emitting unit 52 using the above-mentioned modulated pulse (Fig. 13(c)) by the first photodiode 61a of the first light receiving unit 61, converts it photoelectrically, and then demodulates, amplifies, and shapes it by the calculation control unit 61b. The demodulated, amplified, and shaped signal is then input to the first encoder 62, and encoded based on a predetermined rule, thereby detecting the finally transmitted coded information (Fig. 13(a)). Then, based on this detected information, the work coil 5, the heater 11, the fan 17, etc. are controlled.

These configurations and operations are exactly the same when encoded information is transmitted from the second light-emitting unit 64 (second infrared light-emitting diode 64a) on the sub-microcomputer 40B side to the second light-receiving unit 53 (second photodiode 53a) on the main microcomputer 40A side via the second light guide 72, as shown in Figures 7 and 12. The only difference is that the transmission and reception directions are reversed. The second light guide 72 is also an optical tube of a predetermined diameter with an optical transmission path 70 formed on the inside, as shown in Figures 8 and 9.

This enables proper bidirectional control by the main microcomputer unit 40A on the microcomputer board 50 and the sub-microcomputer unit 40B on the control board 60. This control also eliminates the risk of malfunction due to the intrusion of external noise, and the high-speed digital optical communication improves control responsiveness, resulting in highly functional rice cooker control.

The first light receiving section 61 on the sub-microcomputer unit 40B side and the second light receiving section 53 on the main microcomputer unit 40A side can also be configured with only a photodiode (or phototransistor). In that case, however, they can only receive the transmission signal modulated by the carrier pulse and perform photoelectric conversion, and separate circuits must be provided for demodulation, amplification, and shaping, resulting in a complex circuit configuration and increased component costs.

In this embodiment, as shown in Figures 6, 11, 7 and 12, these circuits are modularized as operational control units 61b, 53b using operational amplifiers, forming integrated light receiving units 61, 53 including photodiodes 61a, 53a. This allows the light receiving units 61, 53 to achieve photoelectric conversion, demodulation, amplification and shaping functions as a single unit.

As a result of the above, the configuration of this embodiment eliminates the risk of electromagnetic noise entering the control unit from the electrical wiring material configured as a wire harness such as a conventional flexible flat cable, the generation of radiated noise from the electrical wiring material to the outside, and the risk of wire breakage due to the opening and closing of the lid, thereby greatly improving the reliability of the control function.

Also, unlike the photocoupler method, bidirectional communication and control are possible regardless of whether the lid is open or closed. Furthermore, the increased communication speed achieved by optical communication can greatly improve control responsiveness, resulting in a highly functional electric rice cooker.

In addition, since the microcomputers on the lid and main body have optical communication capabilities, it will be easier to install IoT-related peripheral devices that enable optical communication with the outside world around the electrical boards on the lid and main body, making it possible to increase functionality. Furthermore, the realization of a wireless communication line with no electrical resistance, known as optical communication, will also reduce power consumption, wiring costs, and connection work costs.

<Modification>
In the above embodiment, the first light guide 71 and the second light guide 72 are each formed of one light tube.

However, in reality, the number of communication paths is insufficient with only one bidirectional communication path each. In such cases, a composite optical tube (integrally molded) is used in which multiple optical tubes are arranged side by side and integrated, as shown in Figure 15.

At first glance, the composite optical tube in Figure 15 looks like a flexible flat cable, but it is merely a light guide and not a wire harness that picks up electromagnetic noise or is a source of electromagnetic noise. Also, there are no breaks in the wire like with conductive bands.

<Configuration of electric rice cooker according to the second embodiment>
Next, Figs. 16 and 17 show the arrangement structure of a light guide in an electric rice cooker according to a second embodiment of the invention of this application.

The electric rice cooker according to the second embodiment is characterized in that the first and second light guides 71, 72 made of light tubes in the configuration of the electric rice cooker according to the first embodiment described above are disposed not behind the hinge unit 9 but in a manner that they penetrate through the hinge shaft 9a of the hinge unit 9. For this reason, the hinge shaft 9a of the hinge unit 9 is formed into a hollow pipe structure with a diameter sufficient to allow the first and second light guides 71, 72 made of light tubes to pass through, as shown in detail in Fig. 17, for example.
In the second embodiment, the first and second light guides 71, 72 are arranged in parallel and close to each other, passing through the hinge shaft 9a having a hollow structure, as shown in Figures 16 and 17, for example.

The first and second light guides 71, 72 that optically connect the first light emitter 52 and the first light receiver 61, and the second light emitter 64 and the second light receiver 53 of the microcomputer board 50 having the main microcomputer unit 40A and the control board 60 having the sub-microcomputer unit 40B to each other can also be arranged through the back side of the hinge unit 9 (hinge shaft 9a) as in the first embodiment above.

However, if this is done, local bending deformation is repeated at the hinge axis 9a in the middle, for example by 90 degrees (see Figure 2) when the lid 2 is closed, and by about 110 degrees (see Figure 3) when the lid 2 is open, in a direction perpendicular to the axis. As a result, even though the silicone rubber optical tube (Figures 8 to 10) has a simple tube structure with no electrically conductive parts and is sufficiently strong, it still experiences a certain degree of fatigue and cross-sectional deformation.

In contrast, as shown in Figure 17, if the hinge shaft 9a is made of a hollow pipe structure and the first and second light guides 71, 72 made of silicone rubber light tubes are arranged from one end side to the other end of the hinge shaft 9a of the hollow pipe structure, penetrating its inside, local bending deformation in the direction perpendicular to the axis is eliminated, and fatigue and cross-sectional deformation are more effectively reduced.

Of course, even in this case, some deformation in the axial torsional direction occurs in the tube portion inside the hinge shaft 9a when the cover 2 is opened and closed, but since the length of the portion penetrating inside the hinge shaft 9a is long enough in both directions, the amount of deformation is fully absorbed by that length and it is unlikely to become a localized deformation. Therefore, fatigue and cross-sectional deformation are hardly an issue. As a result, durability is improved and stable optical communication functions can be maintained.

<Configuration of the light guide of the electric rice cooker according to the third embodiment>
Next, FIGS. 18 to 20 show the configuration of a light guide in an electric rice cooker according to a third embodiment of the invention of this application.

The electric rice cooker according to the third embodiment is characterized in that the first and second light guides 71, 72 in the electric rice cooker according to the first and second embodiments described above have been changed from hollow optical tubes with total reflection surfaces to two-layer optical cables made of a transparent core member 75 with a high refractive index for infrared rays and a cladding member 76 with a low refractive index for infrared rays that covers the outer periphery of the core member 75. The configuration of the other parts is exactly the same as that of the first and second embodiments described above.

In the case of such a configuration, as shown in FIG. 19, for example, infrared light irradiated in the axial direction from the first light emitter 52 on the microcomputer board 50 side and the second light emitter 64 on the control board 60 side enters the core member 75 from one end of the optical cable at a shallow entrance angle, and while being totally reflected at the boundary surface between the core member 75 and the cladding member 76, it is efficiently propagated to the first light receiver 61 on the control board 60 side and the second light receiver 53 on the microcomputer board 50 side without interference. Therefore, the signal transmission and reception performance is improved as in the case of the optical tube described above. Of course, there is no intrusion of electromagnetic external noise, and no radiation of electromagnetic noise to the outside.

In this case, too, by selecting a synthetic resin material with sufficient flexibility and suppleness for the core member 75 and cladding member 76, it is possible to easily construct flexible light guides 71, 72 that can be flexibly bent in response to the opening and closing of the lid 2. As a result, even if they come into contact with the hinge shaft 9a when arranged behind the hinge unit 9, they are hardly subjected to stress, and durability is increased. Also, unlike the case of an optical tube in which the transmission path is simply a hollow space, the transparent core member 75 does not deform the cross-sectional shape of the transmission path, allowing for more stable transmission and reception. Strength is also improved.

<Modification>
In the above embodiment, the first light guide 71 and the second light guide 72 are each formed of one optical cable.

However, in reality, the number of communication paths is insufficient with only one bidirectional communication path each. In such cases, a composite optical cable is used in which multiple optical cables are arranged side by side and integrated, as shown in Figure 20.

In this case, unlike the optical tube of FIG. 15, multiple optical cables of FIG. 18 described above are arranged in parallel and covered in a flat state. In this case, the synthetic resin material of the covering portion 77 is naturally selected to have sufficient flexibility and pliability similar to that of the cable portion.

At first glance, the composite optical cable in Figure 20 looks like a flexible flat cable, but it is merely a light guide and not a wire harness that picks up electromagnetic noise or is a source of electromagnetic noise. Also, there are no breaks like with conductive bands.

<Configuration of electric rice cooker according to the fourth embodiment>
Next, Figs. 21 and 22 show the configuration of an electric rice cooker according to a fourth embodiment of the invention of this application.

The block diagram in FIG. 21 corresponds to the block diagram in FIG. 5 of the first embodiment described above, and in the case of the electric rice cooker according to the fourth embodiment of the invention of this application, the power cable 36 and the connector 65 on the control board 60 side and the connector 55 on the microcomputer board 50 side corresponding to the power cable 36 in the configuration of the electric rice cooker of the first embodiment described above are eliminated, and instead, a power transmission unit (wireless power transmission unit) 31 is provided on the control board 60 side, and a corresponding power receiving unit (wireless power receiving unit) 56 and AC power circuit 57 are provided on the microcomputer board 50 side, making it a completely wireless structure (electrically conductorless structure) including the communication unit and power supply unit.

That is, in this fourth embodiment, the power of the AC power supply circuit 33 on the control board 60 side is wirelessly transmitted to the power receiving unit 56 on the microcomputer board 50 side via the power transmission unit 35, and is then supplied from the power receiving unit 56 to the AC power supply circuit 57 on the control board 60 side. The power from the AC power supply circuit 57 is supplied as a driving source for the lid heater 23 as in the case of the power cable 36 (power supply wiring is not shown), and is also distributed via the control power supply circuit (rectifier circuit/constant voltage power supply circuit) 37 as an operating power supply for driving the main microcomputer unit 40A, an operating power supply for driving the liquid crystal panel 20i, and a power supply for charging the rechargeable battery 38 for backup and other control purposes, etc.

In this embodiment, the power transmission unit 35 on the control board 60 side and the power receiving unit 56 on the microcomputer board 50 side, which perform the wireless power transmission, form a magnetic resonance type wireless power transmission system that employs LC circuits in the power transmission device 35C and the power receiving device 56A, respectively, as shown in FIG. 22, and transmits power efficiently by resonating with the high frequency power supply circuit 35A.

That is, in the case of the same configuration, the power transmission unit 35 on the control board 60 side described above is composed of a high-frequency power supply circuit 35A, a first matching circuit (first impedance matching circuit) 35B, and a power transmission device 35C. The AC power from the AC power supply circuit 33 is converted into a predetermined high-frequency power supply through the high-frequency power supply circuit 35A, and the change in the magnetic field caused by this high-frequency power supply is transmitted from the power transmission coil L1 of the power transmission device 35C to the power receiving coil L2 of the power receiving device 56A on the power receiving unit 56 side. The frequency of the high-frequency power supplied from the high-frequency power supply circuit 35A to the power transmission coil L1 of the power transmission device 35C is adjusted by the capacitance C1 of the LC circuit constituting the power transmission device 35C. This power supply frequency is adjusted so that the mutual resonant frequencies (self-resonant frequencies) always match, taking into account the optimal distance (distance at which the transmission efficiency is highest) between the power transmission device 35C and the power receiving device 56A. The power transmission coil L1 and the power receiving coil L2 are each formed, for example, by an air-core coil. The first matching circuit (first impedance matching circuit) 35B has an impedance matching function at the power supply point of the power transmission coil L1, and by achieving this matching, highly efficient high-frequency transmission of the power transmission coil L1 is realized.

The magnetic resonance type wireless power transmission system is a magnetic field coupling type power transmission system similar to the electromagnetic induction type wireless power transmission system, but if the power transmission coil L1 of the power transmission device 35C and the power receiving coil L2 of the power receiving device 56A are placed at the same optimal resonance distance, it is not affected by the magnetic field coupling coefficient as in the electromagnetic induction type, and even if the center positions of the power transmission coil L1 and the power receiving coil L2 are shifted, the transmission efficiency does not decrease significantly, and the maximum transmission efficiency due to LC resonance can be obtained.

The power receiving unit 56 is composed of a power receiving device 56A consisting of an LC resonant circuit (L2, C2) corresponding to the LC resonant circuit (L1, C1) of the transmitting device 35C, a second matching circuit (second impedance matching circuit) 56B, and a power conversion circuit 56C that converts the received high-frequency power to a normal AC power. The AC power transmitted at a high frequency from the power transmitting device 35C in a resonant state is received by the power receiving device 56A, and after the impedance at the power receiving point (load end) is matched by the second matching circuit 56B, it is input to the power conversion circuit 56C, efficiently converted back to a normal AC power, and then supplied to the AC power circuit 57 on the microcomputer board 50 side described above.

Wireless power transmission (WPT) methods include radiative types that use laser light, microwaves, and ultrasound, as well as non-radiative types that use electromagnetic induction, magnetic field resonance, and annular solenoids. With radiative types, the power transmission effect can be increased even if the power supply unit and the power receiving unit are not in close proximity, and there is no need to worry about misalignment between the power transmitting and receiving units. In addition, the power transmission distance is large. However, with current technology, the power transmission loss is large and it is not practical.

On the other hand, in the case of magnetic field coupling types other than the magnetic field resonance type, such as electromagnetic induction types and annular solenoid types, the power transmission effect cannot be increased unless the power transmission unit and the power receiving unit are in close proximity, and they are vulnerable to misalignment between the power transmission and power receiving units, and if there is a misalignment, the transmission efficiency drops significantly. Therefore, as already mentioned, in the case of electric rice cookers, there is a problem that they only function when the lid 2 is completely closed.

However, even in the case of the magnetic field coupling method, in the case of the magnetic field resonance method described above (power transmission device in FIG. 22), the power energy supplied from the power transmission device 35C is transmitted through the magnetic resonance space only to the power receiving device 56A that is resonating at the same frequency, making it possible to transmit power with high efficiency even if the relative positions of the power transmitting and receiving devices 35C and 56A are misaligned. Also, even if there is a metal object between the power transmitting and receiving devices 35C and 56A inside the lid 2, it will not be heated, so it is safe.

In addition, in the configuration of FIG. 22, if a repeater device (relay device) consisting of an LC circuit that resonates at the same frequency as the power transmitting and receiving devices 35C and 56A is provided between the power transmitting and receiving devices 35C and 56A, it becomes possible to further extend the power transmission distance. In the case of the configuration of FIG. 22, a power transmission distance of about 50 to 80 cm is fully possible, and a power transmission efficiency of about 80 to 90% can be achieved.

In the case of the electric rice cooker of the present invention, the repeater device (relay device) can be easily installed, for example, on the inside rear end of the lid body 2.

Therefore, with this configuration, even when the lid 2 is open, the power required for the first microcomputer unit 40A, the operation switches 20b to 20g, the liquid crystal panel 20i, and the rechargeable battery 38 on the lid 2 side can be supplied wirelessly. As a result, even when the lid 2 is open, the liquid crystal panel 20i and the various operation switches 20b to 20g, such as the keep warm cancel switch 20d, can function.

In addition, by adopting this configuration, the lid 2 and the rice cooker main body 1 can be made completely wireless (wireless), completely eliminating the need for electrical connections, making assembly during manufacturing significantly easier. As a result, there is no risk of damage to the circuit board due to incorrect power cable connections.

<Other embodiments>
In addition, charging of the rechargeable battery 38 in the above-mentioned fourth embodiment can be achieved not only by the above-mentioned wireless power transmission, but also by providing a solar panel on the side of the lid body 2 or by providing a temperature difference power generation device utilizing the Seebeck effect inside the lid body 2.

In addition, in the above description of the fourth embodiment, a magnetic resonance type wireless power transmission system that can be fully realized and implemented with current technology is used, but it goes without saying that depending on the progress of technological development, the invention of this application may also be configured to use a radiation type wireless power transmission system that uses laser light, microwaves, etc.

1: Rice cooker body 2: Lid 3: Inner pot 5: Electromagnetic induction coil 9: Hinge unit 9a: Hinge shaft 20: Nameplate 40A: Main microcomputer unit 40B: Sub-microcomputer unit 50: Microcomputer board 51: First light-emitting unit drive means 52: First light-emitting unit 53: Second light-receiving unit 54: Second encoder 60: Control board 61: First light-receiving unit 62: First encoder 63: Second light-emitting unit drive means 64: Second light-emitting unit 71: First light guide 72: Second light guide

Claims (2)

an electric rice cooker comprising: a rice cooker body; a lid body that is pivotally supported on the rear end side of an opening of the rice cooker body via a hinge shaft so as to be openable and closable, and that covers the opening of the rice cooker body in a closed state; a first electric board having a first microcomputer provided on the inside of the lid body; and a second electric board having a second microcomputer provided on the inside of the rice cooker body, wherein a light-emitting unit and a light-receiving unit are provided on the first electric board having the first microcomputer and the second electric board having the second microcomputer , respectively, and the light-emitting unit and the light-receiving unit are connected to each other via a flexible light guide so as to be capable of optical communication ;
An electric rice cooker characterized in that a flexible light guide that optically connects the light emitting section and the light receiving section of each of the first electrical board having the first microcomputer and the second electrical board having the second microcomputer is arranged through the back side of the hinge axis . an electric rice cooker comprising: a rice cooker body; a lid body that is pivotally supported on the rear end side of an opening of the rice cooker body via a hinge shaft so as to be openable and closable, and that covers the opening of the rice cooker body in a closed state; a first electric board having a first microcomputer provided on the inside of the lid body; and a second electric board having a second microcomputer provided on the inside of the rice cooker body, wherein a light-emitting unit and a light-receiving unit are provided on the first electric board having the first microcomputer and the second electric board having the second microcomputer, respectively, and the light-emitting unit and the light-receiving unit are connected to each other via a flexible light guide so as to be capable of optical communication;
the hinge shaft has a hollow pipe structure, and flexible light guides for optically connecting the light emitting section and the light receiving section of the first electric board having the first microcomputer and the second electric board having the second microcomputer are disposed penetrating the inside of the hinge shaft having the hollow pipe structure from one end side to the other end side.

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