Patent Description:
For example, Patent Document <NUM> discloses a freezer capable of thawing foods in a frozen state. The refrigerator of Patent Document <NUM> has a high-frequency heating chamber that contains foods to be thawed and that subjects the contained foods to high-frequency heating (dielectric heating). The high-frequency heating chamber is configured so that cold air from a freezing chamber can be introduced. As a result, the high-frequency heating chamber is used as the freezing chamber when not used for thawing.

Post-published Patent Document <NUM> describes a refrigerator that includes at least one storage chamber and uses an electromagnetic wave to heat a stored object inside the storage chamber. A first electromagnetic wave shield is provided on a door of the storage chamber, and a second electromagnetic wave shield is provided on a housing part of the refrigerator that is in contact with the door while the door is closed.

Patent Document <NUM> describes a refrigerator provided with storage chambers including a refrigeration chamber, a first freezing chamber, a second freezing chamber, etc. At least one of the storage chambers is a compartmental storage chamber having, on the inside thereof, a first storage compartment in which a predetermined temperature range that has been determined for the storage chamber is maintained, and a second storage compartment having a temperature range different from the predetermined temperature range.

Patent Document <NUM> describes a refrigerator, wherein a part or all of a refrigerating chamber is formed in an electric field processing chamber, in which a flat high voltage electrode, a flat counter electrode arranged oppositely to the high voltage electrode and a high voltage power source are arranged. When a door of the chamber is opened, a limit switch is so provided as not to energize the power source. Further, a time control means is so provided as to energize the power source for a predetermined time only when storage of food is sensed by food storage sensing means.

In the case of the freezer described in Patent Document <NUM>, however, when desiring to thaw some of multiple foods preserved frozen in the high-frequency heating chamber used as the freezing chamber, foods not desired to be thawed need to be moved from the high-frequency heating chamber.

It is therefore an object of the present invention, in a refrigerator including a cooling/heating chamber capable of cooling and heating foods, to heat foods in the cooling/heating chamber without moving foods other than the foods to be heated from the cooling/heating chamber.

According to the present invention, it is possible, in the refrigerator including the cooling/heating chamber capable of cooling and heating foods, to heat foods in the cooling/heating chamber without moving foods other than the foods to be heated from the cooling/heating chamber.

These aspects and features of the present invention will become apparent from the following description related to preferred embodiments about the accompanying drawings, in which:.

According to the present invention, there is disclosed a refrigerator according to the technical features of independent claim <NUM>.

Thereby it is possible, in the refrigerator including the cooling/heating chamber capable of cooling and heating foods, to heat foods in the cooling/heating chamber without moving foods other than the foods to be heated from the cooling/heating chamber.

The refrigerator may include an operating unit that receives a user's instruction to switch from a normal operation preserving the foods at a first cooling preservation temperature to the zone heating operation heating foods placed in the heating zone. This enables only foods placed in the heating zone to be heated.

The oscillation electrode may have a cold air passage hole through which the cold air passes toward the cooling/heating chamber. This enables the oscillation electrode to be cooled.

The refrigerator may include a drawer containing the foods that retreats from and enters the cooling/heating chamber, and a presenting unit that presents to a user that a portion of the drawer arranged in the heating zone is a place where foods to be heated are placed. As a result, foods to be heated can be placed in the heating zone by the user.

The drawer may have, on at least one of a bottom part and a lateral wall part of the drawer, a through hole extending through from the interior of the drawer toward the exterior. This enables cold air in the drawer to flow out smoothly to the exterior.

The heating zone may be located in front of the refrigerator with respect to the non-heating zone. This enables foods heated in the heating zone to be removed immediately.

The refrigerator may include: a compressor that circulates a refrigerant; a cooler through which the refrigerant passes; a cooling fan that blows cold air, which is air cooled by the cooler, toward the cooling/heating chamber; a damper that is disposed on a flow passage between the cooling/heating chamber and the cooling fan, for controlling a flow rate of cold air flowing into the cooling/heating chamber by opening and closing; and a temperature sensor that measures an internal temperature of the cooling/heating chamber. During the zone heating operation, the internal temperature of the cooling/heating chamber is maintained at the first cooling preservation temperature that is the temperature in the normal operation, by executing output control of the compressor, rotation speed control of the cooling fan, and opening/closing control of the damper, based on a result of measurement by the temperature sensor. As a result, foods not to be heated can be preserved frozen.

The refrigerator may include:
a reflected wave detecting unit that detects a reflected wave returning to the oscillating unit; and a reflectance calculating unit that calculates a reflectance which is a ratio of the reflected wave to an incident wave output from the oscillating unit. In this case, at a first timing where a reflectance lower than a first threshold value is calculated, the operation is switched from the normal operation to a quenching operation that more rapidly cools the cooling/heating chamber than during the normal operation. At a second timing after the start of the quenching operation where the reflectance reaches a second threshold value that is a value lower than the first threshold value, the oscillating unit starts to intermittently apply an AC voltage to between the oscillation electrode and the counter electrode. When a predetermined time elapses from a third timing after the oscillating unit starts to intermittently apply the AC voltage where the reflectance reaches a third threshold value that is a value lower than the second threshold value, the quenching operation terminates, with the result that the normal operation is resumed and the intermittent application of the AC voltage by the oscillating unit terminates. This enables foods contained in the cooling/heating chamber to be rapidly cooled automatically.

When the compressor is operating during the normal operation, the oscillating unit may apply an AC voltage to between the oscillation electrode and the counter electrode. As a result, generation of frost can be suppressed.

The first cooling preservation temperature may be a freezing temperature.

Hereinafter, a refrigerator according to an embodiment of the present invention will be described with reference to the drawings. <FIG> is a longitudinal sectional view of the refrigerator of the present embodiment. In <FIG>, the left side is a front surface side of the refrigerator, and the right side is a back surface side of the refrigerator. Further, <FIG> is a block diagram showing a control system of the refrigerator.

As shown in <FIG>, a refrigerator <NUM> includes a main body <NUM>. The main body <NUM> is configured from outer housing <NUM> made of a metal material that constitutes an outer surface of the refrigerator <NUM>, an inner housing <NUM> made of a resin material such as ABS for example that constitutes an inner surface of the refrigerator <NUM>, and an insulation material <NUM> such as hard urethane foam that is filled in a space between the outer housing <NUM> and the inner housing <NUM>.

The main body <NUM> of the refrigerator <NUM> includes a plurality of storage chambers for storing foods (foodstuffs, processed foodstuffs, etc.). In the case of the present embodiment, the storage chambers include, from the top, a refrigerating chamber 12a, a freezing/thawing chamber 12b, a freezing chamber 12c, and a vegetable chamber 12d. Note that although not shown, an ice making chamber making ice is disposed on the right side (back side in the drawing) of the freezing/thawing chamber 12b. Further, the refrigerator <NUM> can also contain products other than foods.

The refrigerating chamber 12a is a space maintained in a temperature range where foods do not freeze, for example, in the temperature range of <NUM> to <NUM>. The freezing chamber 12c is a space maintained in a temperature range where foods freeze, for example, in the temperature range of -<NUM> to -<NUM>. The vegetable chamber 12d is a space maintained in a temperature range equal to or higher than that of the refrigerating chamber 12a, for example, in the temperature range of <NUM> to <NUM>. The freezing/thawing chamber 12b will be described later.

In the case of the present embodiment, a machine chamber 12e is disposed on top of the main body <NUM> of the refrigerator <NUM>. The machine chamber 12e houses a compressor <NUM>, etc. that make up a freezing cycle of the refrigerator <NUM> and that circulate a refrigerant for the freezing cycle. Note that alternatively, the machine chamber 12e may be disposed at the bottom of the main body <NUM> of the refrigerator <NUM>.

In the case of the present embodiment, a cooling chamber 12f is disposed on a back surface side of the freezing chamber 12c and the vegetable chamber 12d. In the cooling chamber 12f, a cooler <NUM> is arranged that makes up the freezing cycle of the refrigerator <NUM> and that allows the refrigerant to pass therethrough. Further, in the cooling chamber 12f, a cooling fan <NUM> is disposed that blows air (cold air) of the cooling chamber 12f cooled by the cooler <NUM> toward the refrigerating chamber 12a, the freezing/thawing chamber 12b, the freezing chamber 12c, and the vegetable chamber 12d. Furthermore, as shown in <FIG>, dampers 26A to 26D for controlling the flow rate of cold air flowing into the chambers 12a to 12d are arranged on flow passages between the chambers 12a to 12d and the cooling fan <NUM> (only a damper 26B is shown in <FIG>).

Moreover, as shown in <FIG>, the refrigerating chamber 12a, the freezing/thawing chamber 12b, the freezing chamber 12c, and the vegetable chamber 12d include temperature sensors 28A to 28D, respectively, that measure their internal temperatures.

As shown in <FIG>, based on the results of measurement of the plural temperature sensors 28A to 28D, a control unit <NUM> of the refrigerator <NUM> executes cooling control, that is, executes output control of the compressor <NUM>, rotation speed control of the cooling fan <NUM>, and opening/closing control of each of the dampers 26Ato 26D, whereby the temperatures within the refrigerating chamber 12a, the freezing/thawing chamber 12b, the freezing chamber 12c, and the vegetable chamber 12d are properly kept. The control unit <NUM> is a substrate including a processor such as a CPU for example, a storage device storing programs, etc., and a circuit, and the processor controls the compressor <NUM>, the cooling fan <NUM>, and the dampers 26A to 26D in accordance with the programs stored in the storage device.

As shown in <FIG>, in the case of the present embodiment, since the refrigerator <NUM> is operated by the user, the refrigerator <NUM> includes an operating unit <NUM> for operation thereof and particularly of the freezing/thawing chamber 12b. Note that the operating unit <NUM> may be a touch panel incorporated in the refrigerator <NUM> and/or a user's mobile terminal. In the case where the operating unit <NUM> is the mobile terminal, software (an application) for operating the refrigerator <NUM> is installed in the mobile terminal. Hereinafter, details of the freezing/thawing chamber 12b will be described.

<FIG> is an enlarged sectional view of the freezing/thawing chamber <NUM>. Further, <FIG> is an enlarged sectional view of the freezing/thawing chamber showing the flow of cold air. Note that the flow of cold air is indicated by an alternate long and short dashed line.

As shown in <FIG>, in the case of the present embodiment, the freezing/thawing chamber 12b is configured by a heating module <NUM> incorporated in the main body <NUM> of the refrigerator <NUM>.

<FIG> is a sectional view of the heating module and <FIG> is a sectional view of part of the main body of the refrigerator before incorporating the heating module. <FIG> is an exploded sectional view of the heating module. <FIG> is a sectional view of the heating module taken along line A-A of <FIG>.

As shown in <FIG> and <FIG>, the heating module <NUM> has a rectangular parallelepiped shape and is a double-walled structure including an inner case <NUM> and a shield case <NUM> containing the inner case <NUM>. The shield case <NUM> functions as a housing of the heating module <NUM>. The inner case <NUM> defines a containing chamber for containing foods, that is, the freezing/thawing chamber 12b.

The inner case <NUM> is made of an insulating material such as resin and has a box shape having an opening on the front side. The shield case <NUM> is configured of a material containing metal and is made of e.g. a metal material such as aluminum. Further, the shield case <NUM> has an opening on the front side and is in the shape of a box storing the inner case <NUM>.

In the case of the present embodiment, as shown in <FIG>, the heating module <NUM> includes a drawer <NUM> for containing foods that retreats from and enters the freezing/thawing chamber 12b. Specifically, the drawer <NUM> includes a containing part 46a for containing foods and a door part 46b disposed on the front side of the containing part 46a that opens and closes the freezing/thawing chamber 12b. The containing part 46a is made of a resin material. Further, metal rails <NUM> guiding the drawer <NUM> when sliding in and out are disposed on the inner wall surface of the inner case <NUM>. Such a drawer <NUM> makes it easier to put/remove foods into/from the freezing/thawing chamber 12b.

In the case of the present embodiment, as shown in <FIG> and <FIG>, the heating module <NUM> has cold air inlet holes for introducing cold air (dashed line) into the freezing/thawing chamber 12b disposed thereinside and cold air outlet holes for discharging cold air in the freezing/thawing chamber 12b. Specifically, the cold air inlet holes of the heating module <NUM> include a plurality of through holes 44a formed on a ceiling part of the shield case <NUM> and a plurality of through holes 42a formed on a ceiling part of the inner case <NUM>. These through holes 42a and 44a enable cold air blown from the cooling fan <NUM>, passing through the damper 26B, and flowing through a flow passage <NUM> to be introduced into the interior of the freezing/thawing chamber 12b.

The cold air outlet holes of the heating module <NUM> include a plurality of through holes 42b formed on a bottom part of the inner case <NUM> and a plurality of through holes 44b formed on a bottom part of the shield case <NUM>. These through holes 42b and 44b enable cold air in the freezing/thawing chamber 12b to return the cooling chamber 12f.

Note that in the case of the present embodiment, cold air flowing out from the through holes 42b and 44b as the cold air outlet holes returns via the freezing chamber 12c to the cooling chamber 12f. For that reason, as shown in <FIG>, on a partition part 12j of the main body <NUM> of the refrigerator <NUM> that partitions a space <NUM> in which the freezing/thawing chamber 12b is incorporated and the freezing chamber 12c, a through hole <NUM> is disposed that allows the space <NUM> and the freezing chamber 12c to communicate with each other.

Further, as shown in <FIG> and <FIG>, to ensure a smooth flow of cold air in the drawer <NUM> to the cooling chamber 12f (i.e. the freezing chamber 12c), it is preferred that the containing part 46a of the drawer <NUM> have, at least one of its bottom part and its lateral wall part, through holes 46c extending through from the inside of the drawer <NUM> toward the outside. In the case of the present embodiment, disposed as the through holes 41c are a plurality of slit holes 46c extending in the top-bottom direction on a back-side lateral wall part of the drawer <NUM> and juxtaposed in the left-right direction.

To thaw a food in a frozen state within the freezing/thawing chamber 12b, as shown in <FIG>, the heating module <NUM> includes a heating unit <NUM>.

<FIG> is a block diagram showing a control system of the heating unit of the heating module.

As shown in <FIG>, the heating module <NUM> includes, as components of the heating unit <NUM>, an oscillation electrode <NUM> and a counter electrode (counter electrode unit) <NUM> facing the oscillation electrode <NUM>.

In the case of the present embodiment, the oscillation electrode <NUM> is a flat electrode made of a metal material as shown in <FIG> and is arranged in a space between the ceiling part of the inner case <NUM> and the ceiling part of the shield case <NUM> as shown in <FIG>. Further, the oscillation electrode <NUM> has a plurality of cold air passage holes 52a through which cold air passes. By virtue of these cold air passage holes 52a, it is possible to cool the oscillation electrode <NUM> by cold air and to introduce cold air also into the region of the freezing/thawing chamber 12b located below the oscillation electrode <NUM>.

In the case of the present embodiment, the counter electrode <NUM> is a portion 44c of the bottom part of the shield case <NUM>. Further, the counter electrode <NUM> (portion 44c) faces the oscillation electrode <NUM> in the top-bottom direction with the inner case <NUM>, i.e. the freezing/thawing chamber 12b in between. The oscillating electrode and the counter electrode need not have the same area.

The heating unit <NUM> includes, as shown in <FIG>, an oscillating circuit (oscillating unit) <NUM> that is controlled by the control unit <NUM> to apply an AC voltage of a predetermined VHF band frequency e.g. of <NUM> to between the oscillation electrode <NUM> and the counter electrode <NUM>. Specifically, the oscillating circuit <NUM> is a circuit formed on a substrate and is electrically connected to the oscillation electrode <NUM> and the counter electrode <NUM>. Further, the oscillating circuit <NUM> converts an AC voltage from a power supply unit <NUM> of the refrigerator <NUM> connected to a commercial power supply and applies the converted AC voltage to between the oscillation electrode <NUM> and the counter electrode <NUM>.

When the AC voltage is applied, an alternating electric field occurs between the oscillating electrode <NUM> and the counter electrode <NUM>. By this alternating electric field, a food placed between these electrodes <NUM> and <NUM> i.e. a food contained in the drawer <NUM> in the freezing/thawing chamber 12b is dielectrically heated. As a result, the food in the frozen state is thawed.

Note that in the case of the present embodiment, as shown in <FIG> and <FIG>, the oscillation electrode <NUM> and the counter electrode <NUM> are arranged so as to face each other with part of the freezing/thawing chamber 12b in between, instead of facing each other with the whole thereof in between. In consequence, the freezing/thawing chamber 12b is divided into a thawing zone (heating zone) DZ (region indicated by a broken line cross-hatching) that is a space where foods to be thawed (to be heated) are placed and a non-thawing zone (non-heating zone) NDZ that is a space continuous with the thawing zone DZ where foods not to be thawed (not to be heated) are placed. That is, between the oscillating electrode <NUM> and the counter electrode <NUM>, the thawing zone DZ exists but the non-thawing zone NDZ does not exist.

By dividing the freezing/thawing chamber 12b into the thawing zone DZ and the non-thawing zone NDZ in this manner, only some of a plurality of foods contained in the freezing/thawing chamber 12b can be thawed. For this reason, when thawing, foods not desired to be thawed need not be moved from the freezing/thawing chamber <NUM>, for example, to the freezing chamber 12c. Further, in the case where the operating unit <NUM> is configured so that the start time of thawing can be reserved, a food placed in the thawing zone DZ is kept frozen until thawing is started, and thereafter is automatically thawed as it is.

Further, in the case of the present embodiment, the thawing zone DZ lies on the front side of the refrigerator <NUM> with respect to the non-thawing zone NDZ. Therefore, the food thawed in the thawing zone DZ can be taken out immediately.

To indicate to the user to place the food to be thawed in this thawing zone DZ, it is preferred to dispose a presenting unit that presents to the user that the part of the drawer <NUM> arranged in the thawing zone DZ is the place where the food to be thawed is placed. The presenting unit may be, for example, an image or characters printed on the bottom surface of the drawer <NUM>. Further, for example, the presenting unit may be a partition wall disposed in the drawer <NUM> that indicates a boundary between the thawing zone DZ and the non-thawing zone NDZ. Further, the front-back positional relationship between the thawing zone DZ and the non-thawing zone NDZ may be reversed. If reversed, the length of a connection member <NUM> is shortened and the heating efficiency is improved.

As shown in <FIG>, when the oscillation electrode <NUM> and the counter electrode <NUM> are viewed in the direction facing each other (the top-bottom direction of the refrigerator <NUM>), the oscillation electrode <NUM> and the counter electrode <NUM> are preferably positioned on the inner case <NUM> so as not to overlap the rails <NUM>. Unlike this, in the case where the rails <NUM> are present between the oscillation electrode <NUM> and the counter electrode <NUM>, an alternating electric field occurs between the oscillation electrode <NUM> and the rails <NUM>, whereas the alternating electric field generated between the oscillation electrode <NUM> and the counter electrode <NUM> weakens, so that the uniformity of the electric field (uniformity of heating) is impaired.

Furthermore, in the case of the present embodiment, the counter electrode <NUM> is a raised portion of the shield case <NUM> that rises toward the oscillation electrode <NUM>, with the result that the counter electrode <NUM> is close to the oscillation electrode <NUM>. Thus, as compared with the case where the counter electrode <NUM> is not the raised portion, a stronger alternating electric field can be generated.

During thawing of a food, that is, when an alternating electric field occurs between the oscillation electrode <NUM> and the counter electrode <NUM>, the shield case <NUM> functions as a shield member that shields this alternating electric field from leaking to the outside. Note that to prevent the alternating electric field from leaking to the outside through the opening on the front side of the shield case <NUM>, as shown in <FIG>, a metal shield plate 46d is disposed within the door part 46b of the drawer <NUM>. The freezing/thawing chamber 12b generating an alternating electric field is surrounded by the shield plate 46d and the shield case <NUM> and is electromagnetically shielded.

As shown in <FIG>, the heating unit <NUM> further includes a matching circuit (matching unit) <NUM> for impedance matching between the oscillation electrode <NUM> and the counter electrode <NUM>. Specifically, the matching circuit <NUM> is a circuit formed on the substrate and is electrically connected to the oscillation electrode <NUM> and the counter electrode <NUM>. In the case of the present embodiment, the counter electrode <NUM> is grounded.

The role of the matching circuit <NUM> will be described. As the thawing of a food progresses, the number of water molecules in the food increases. As the number of water molecules increases, the impedance changes from the matched state and the reflectance increases. Note that the reflectance is a ratio of the reflected wave returning to the oscillating circuit <NUM> to the incident wave output from the oscillating circuit <NUM>.

<FIG> is a diagram showing changes in reflectance during thawing of a food.

In <FIG>, P1 to P5 are timings for the matching circuit <NUM> to re-match the impedance between the oscillation electrode <NUM> and the counter electrode <NUM>. Further, R1 to R3 are threshold values of the reflectance. Further, in reality, instead of the reflectance, threshold values of the reflected power to be easily detected may be set for determination.

The reflectance increases over time as the food begins to thaw. Every time the reflectance reaches a second threshold value R2, the matching circuit <NUM> re-matches the impedance between the oscillation electrode <NUM> and the counter electrode <NUM>. As a result, the reflectance decreases. In this manner, by repeatedly re-matching the impedance between the oscillation electrode <NUM> and the counter electrode <NUM> by the time when thawing of a food terminates, the food can be thawed efficiently while suppressing the loss of electrical energy due to reflection.

In order to calculate this reflectance, as shown in <FIG>, the heating unit <NUM> includes a reflected wave detecting circuit <NUM>. The control unit <NUM> as a reflectance calculating unit calculates the reflectance, based on the incident wave output from the oscillating circuit <NUM> and the reflected wave detected by the reflected wave detecting circuit <NUM>. Every time the calculated reflectance reaches the second threshold value R2, the matching circuit <NUM> re-matches the impedance between the oscillation electrode <NUM> and the counter electrode <NUM>.

In the case of the present embodiment, as shown in <FIG>, the oscillating circuit <NUM>, the matching circuit <NUM>, and the reflected wave detecting circuit <NUM> are incorporated in the heating module <NUM>. Note that the reflected wave detecting circuit <NUM> is formed on the substrate having on which the matching circuit <NUM> is formed.

Specifically, as shown in <FIG>, the oscillating circuit <NUM> and the matching circuit <NUM> are arranged within a shield chamber 44d disposed in the shield case <NUM>. This shield chamber 44d is isolated from the freezing/thawing chamber 12b by a partition wall 44e. By being arranged in such a shield chamber 44d, the oscillating circuit <NUM> and the matching circuit <NUM> are shielded from the alternating electric field generated in the freezing/thawing chamber 12b, and malfunction is suppressed.

Note that the connection member <NUM> electrically connecting the matching circuit <NUM> and the oscillation electrode <NUM> extends through the partition wall 44e. As shown in <FIG>, the connection member <NUM> has a smaller size in the left-right direction than the oscillation electrode <NUM>. This is for suppressing the generation of an alternating electric field between the connection member <NUM> and a portion of the shield case <NUM> that faces it with the freezing/thawing chamber 12b in between. That is, as shown in <FIG>, it is for preventing foods present in the non-thawing zone NDZ located below the connection member <NUM> from being thawed.

Further, as shown in <FIG>, on the oscillating circuit <NUM> there is disposed a connector <NUM> for connection with the control unit <NUM> of the refrigerator <NUM>. Further, also on the matching circuit <NUM> there is disposed a connector <NUM> for connection with the control unit <NUM>. As shown in <FIG>, the connector <NUM> of the oscillating circuit <NUM> engages with a connector <NUM> that is disposed in the space <NUM> of the main body <NUM> of the refrigerator <NUM> in which the heating module <NUM> is incorporated and that is connected to the control unit <NUM>. Further, in the same manner, the connector <NUM> of the matching circuit <NUM> engages with a connector <NUM> that is disposed in the space <NUM> and connected to the control unit <NUM>. The work for engaging these connectors is performed via the through hole <NUM> that allows the space <NUM> and the freezing chamber 12c to communicate with each other. That is, as shown in <FIG>, the through hole <NUM> allowing passage of cold air from the freezing/thawing chamber 12b toward the freezing chamber 12c functions as an access hole for access to the heating module <NUM>.

The advantage of incorporating the oscillating circuit <NUM> and the matching circuit <NUM> (the reflected wave detecting circuit <NUM> included therein) together with the oscillation electrode <NUM> and the counter electrode <NUM> in the heating module <NUM> including the shield case <NUM>, as in the present embodiment, is that a heating test, a noise (alternating electric field) leakage check, and other inspections of these can be performed outside the refrigerator <NUM>.

Dissimilar to this, in case that the oscillation electrode, the counter electrode, the oscillating circuit, the matching circuit, the reflected wave detecting circuit, and the shield component are each incorporated in the interior of the refrigerator main body, the heating test, the noise leakage check, and other inspections need to be performed after incorporating all of these into the refrigerator main body. Therefore, for example, if the result of the heating test is not good or if noise leakage occurs, it is necessary to remove the circuits and shield component incorporated inside the refrigerator main body, which is very troublesome. Also, if noise leakage occurs, the shield member needs to be removed from the refrigerator main body. As a result, the refrigerator manufacturing work including inspections may become complicated.

Thus, by modularizing, as the heating module <NUM>, the oscillation electrode <NUM>, the counter electrode <NUM>, the oscillating circuit <NUM>, the matching circuit <NUM>, the reflected wave detecting circuit <NUM>, and the shield case <NUM> in this manner, the heating test, the noise leakage check, and other inspections can be performed outside the refrigerator <NUM>, consequently facilitating the manufacture of the refrigerator <NUM>. Further, in the case where the refrigerator housing is covered with a metal plate, the leakage noise may not be detected from outside of the refrigerator because it is shielded by the metal plate. In that case, the risk is overlooked that electronic components lying between the metal plate and the heating module <NUM> will not operate normally due to the effects of leak noise, rendering it impossible to perform quality verification as a refrigerator.

The configuration of the freezing/thawing chamber 12b has been described so far. Hereinafter, description will be given of the action (operation) for foods in the freezing/thawing chamber 12b of the refrigerator according to the present embodiment.

In the case of the present embodiment, for foods in the freezing/thawing chamber 12b, the control unit <NUM> executes a normal operation, a quenching operation, a zone thawing operation (zone heating operation), an all-zones thawing operation, and a slight-freezing operation.

The normal operation is an operation to maintain the temperature in the freezing/thawing chamber 12b at a freezing preservation temperature (first cooling preservation temperature) e.g. at a temperature of -<NUM> to -<NUM> that is a freezing temperature at which foods freeze, for preserving foods in the freezing/thawing chamber 12b in a frozen state. That is, it is the operation of maintaining the temperature at the same level as the freezing chamber 12c.

<FIG> is a timing chart of the normal operation.

As shown in <FIG>, in the normal operation, the compressor <NUM> is operated intermittently and the cooling fan <NUM> and the damper 26B are controlled so as to maintain the temperature in the freezing/thawing chamber 12b at a freezing preservation temperature Tf (so as to maintain the food temperature at Tf).

By such an intermittent operation of the compressor <NUM>, the water content of a food evaporates when the compressor <NUM> is stopped (when it is OFF), while the food is frosted when the compressor <NUM> is operating (when it is ON), whereupon the food temperature fluctuates in a wide range.

When a food placed in the thawing zone DZ is frosted, part of food dries, causes a freezer burn, and deteriorates, and hence even if the thawing is performed with high quality, it is not possible to provide the user with a high quality food.

As a countermeasure, in the case of the present embodiment, when the compressor <NUM> is operating, the oscillating circuit <NUM> is turn ON to apply an AC voltage to between the oscillation electrode <NUM> and the counter electrode <NUM>, whereas when the compressor <NUM> is stopped, the oscillating circuit <NUM> is turn OFF to stop applying AC voltage, to thereby reduce the food temperature fluctuations. The output of the oscillating circuit <NUM> at this time is, for example, <NUM> % or more of the freezing capacity.

By such an intermittent operation (i.e. intermittent dielectric heating) of the oscillating circuit <NUM>, the generation of frost on a food placed in the thawing zone DZ is suppressed, and as a result, the occurrence of variations in thawing quality is suppressed. In addition, the growth of ice crystals can be suppressed inside the food placed in the thawing zone DZ. When ice crystals grows to a large extent inside the food, cells and tissues of the food are damaged and water flows out from the damaged cells and tissues when thawed, resulting in deterioration of the food quality. As a countermeasure, dielectric heating is performed to allow electric fields to gather at the tips of ice crystals to suppress the crystal growth, so that the physical deterioration of the food can be suppressed through suppression of the ice crystal size.

The quenching operation is an operation for freezing (quenching) a food to be newly frozen from now on, more rapidly than in the normal operation when the food is placed in the thawing zone DZ of the freezing/thawing chamber 12b. Further, when the food is placed, the quenching operation is automatically started.

<FIG> is a timing chart of the quenching operation.

The reflectance described above is used to detect that a food to be quickly frozen from now on is placed in the thawing zone DZ of the freezing/thawing chamber 12b. As shown in <FIG>, a signal of a door open/close switch is used as a trigger to weakly operate the oscillating circuit <NUM> (small oscillation output), and switch-on is determined by the reflectance. After the switch-on determination, the oscillating circuit <NUM> is periodically operated to detect a change in reflectance, and the frozen state is determined based on the detected change in reflectance, to control the operation of the oscillating circuit <NUM>.

As shown in <FIG>, a food to be quickly frozen from now on is placed in the thawing zone DZ of the freezing/thawing chamber 12b (timing P6), the reflectance decreases. This is because the permittivity between the oscillation electrode <NUM> and the counter electrode <NUM> increases due to the placement of the food to be quickly frozen between the oscillation electrode <NUM> and the counter electrode <NUM>.

In the case of the present embodiment, when the reflectance drops beyond a first threshold value R1, the control unit <NUM> determines that a food to be quickly frozen from now on is placed in the thawing zone DZ of the freezing/thawing chamber 12b, to start the quenching operation instead of the normal operation (timing P6).

When the quenching operation is started, the cooling control is continuously executed as shown in <FIG>. For example, the compressor <NUM> and the cooling fan <NUM> are continuously operated and the damper 26B is kept open. Note that, if there is spare capacity, the output of the compressor <NUM> and the rotation speed of the cooling fan <NUM> may be increased as compared with the normal operation.

As shown in <FIG>, when the reflectance decreases and reaches a second threshold value R2, the rate of change of the reflectance increases. This is because the food temperature has entered a maximum ice crystal formation zone (e.g. -<NUM> to -<NUM>) where ice crystals are easy to grow.

When the food temperature enters the maximum ice crystal formation zone (when the reflectance reaches the second threshold value R2), the oscillating circuit <NUM> of the heating unit <NUM> starts to intermittently apply the AC voltage to between the oscillation electrode <NUM> and the counter electrode <NUM>. At this time, the output of the oscillating circuit <NUM> is, for example, <NUM> W to <NUM> W, which is smaller than the output in the normal operation. Such dielectric heating by the heating unit <NUM> enables a food to be frozen while suppressing the growth of ice crystals within the food.

As the reflectance further lowers to reach a third threshold value R3, the rate of change in reflectance decreases. This is because the food temperature has reached a temperature immediately before passing through the maximum ice crystal formation zone. When a predetermined time t1 elapses after reaching the third threshold value R3, the control unit <NUM> determines that the food temperature has passed through the maximum ice crystal formation zone, allowing the cooling control to return to the control in the normal operation, to terminate the intermittent application of the AC voltage by the oscillating circuit <NUM> (timing P8). As a result, the quenching operation terminates and the normal operation is resumed.

The zone thawing operation (zone heating operation) is an operation thawing (heating) only foods placed in the thawing zone DZ but maintaining foods placed in the non-thawing zone NDZ at the freezing preservation temperature Tf. Different from quenching operation, the zone thawing operation is started when the operating unit <NUM> receives a user's instruction to switch from normal operation to the zone thawing operation. For example, when the user presses a "zone thawing" button on the operating unit <NUM>, the zone thawing operation is started.

<FIG> is a timing chart of the zone thawing operation.

As shown in <FIG>, when the zone thawing operation is started, the oscillating circuit <NUM> of the heating unit <NUM> starts to continuously apply the AC voltage to between the oscillation electrode <NUM> and the counter electrode <NUM>. As a result, thawing of a food A placed in the thawing zone DZ begins and the temperature of the food A begins to rise.

On the other hand, the output of the compressor <NUM>, the rotation speed of the cooling fan <NUM>, and the opening and closing of the damper 26B are controlled so as to maintain a food B placed in the non-freezing zone NDZ at the freezing preservation temperature Tf, that is, so as to maintain the freezing/thawing chamber 12b at the freezing preservation temperature Tf in the normal operation. For example, the damper 26B repeats opening and closing so that the open state and the closed state continue for the same time.

In consequence, the food B placed in the non-thawing zone NDZ is preserved frozen as in the normal operation. In the case of this zone thawing operation, considering the temperature rise in the freezing/thawing chamber 12b caused by the dielectric heating by the heating unit <NUM>, the output of the compressor <NUM> and the rotation speed of the cooling fan <NUM> are higher and the opening time of the damper 26B is longer than in the normal operation.

Further, according to such a zone thawing operation, water vapor generated from the food A being thawed is discharged to the outside of the freezing/thawing chamber 12b by intermittently opening the damper 26B. As a result, the relative humidity of the cooling/thawing chamber 12b does not reach <NUM>% and the generation of frost is suppressed.

When the thawing of the food A placed in the thawing zone DZ is completed, the zone thawing operation terminates.

Note that in the case of the present embodiment, the completion of thawing of a food is determined based on the change in reflectance.

As seen in <FIG> indicating the change in reflectance during thawing of a food, according as the thawing progresses, the reflectance immediately after impedance matching gradually increases. For example, the reflectance at the timing P2 is higher than the reflectance at the timing P1. At the timing <NUM>, unlike the timings P1 to P4 before that, the reflectance after impedance matching has a higher value than the third threshold value R3. By appropriately setting this third threshold value R3, if the reflectance lowered by impedance matching is higher than the third threshold value R3, the impedance matching execution timing P5 can be regarded as the thawing completion timing. Accordingly, if the reflectance does not drop beyond the third threshold value by impedance matching, the control unit <NUM> determines that the thawing of a food has been completed at the execution timing of the impedance matching, to terminate the zone thawing operation. When the zone thawing operation terminates, the normal operation is resumed. However, depending on the amount and physical characteristics of the food, even if not thawed, the reflectance after matching may exceed R3, and even if thawed, it may not reach R2. Therefore, the minimum operation time and the maximum operation time may be set regardless of the threshold values R2 and R3.

The all-zones thawing operation is an operation of thawing (heating) all of foods, that is, not only foods in the thawing zone DZ but also foods in the non-thawing zone NDZ, in the freezing/thawing chamber 12b. Similar to the zone thawing operation, the all-zones thawing operation is also started when the operating unit <NUM> receives a user's instruction to switch from the normal operation to the all-zones thawing operation. For example, when the user presses an "all-zones thawing" button on the operating unit <NUM>, the all-zones thawing operation is started.

<FIG> is a timing chart of the all-zones thawing operation.

As shown in <FIG>, the all-zones thawing operation is the same as the zone thawing operation shown in <FIG> except for the opening time of the damper 26B. Specifically, during the all-zones thawing operation, the damper 26B is almost closed to maintain the temperature of the freezing/thawing chamber 12b that rises due to the dielectric heating of the heating unit <NUM>. However, to reduce the humidity in the freezing/thawing chamber 12b to suppress the generation of frost, the damper 26B opens momentarily to discharge water vapor to the outside. Such an all-zones thawing operation thaws all of foods in the freezing/thawing chamber 12b. The all-zones thawing operation terminates in the same manner as the zone thawing operation. After the termination thereof, the ordinary operation is resumed.

The slight-freezing operation is an operation executed when the food after thawing (thawed food) is left as it is without being removed from the freezing/thawing chamber 12b.

When the thawed food thawed by the zone thawing operation or the all-zones thawing operation is left intact, it is frozen again by the subsequent normal operation. Therefore, the user may remove the thawed food from the freezing/thawing chamber 12b in a re-frozen state. Naturally, the food is hard because it is in a re-frozen state and the user cannot cook it immediately. As a countermeasure, it is conceivable to maintain the temperature of the thawed food at a temperature where it does not freeze after the completion of thawing, but in that case, if left for a long time, the thawed food may be damaged.

Thus, in the case of the present embodiment, the slight-freezing operation is executed that, if the thawed food is left as it is without being removed from the freezing/thawing chamber 12b, maintains the thawed food in a slightly-frozen state, that is, maintains it at a slight-freezing temperature (e.g. -<NUM> to -<NUM>) higher than the freezing preservation temperature (-<NUM> to -<NUM>). The "slightly-frozen state" referred to herein means a state where the intracellular liquid of a food does not freeze, but the extracellular liquid freezes.

Note that the slight-freezing operation (zone slight-freezing operation) performed after the zone thawing operation and the slight-freezing operation (all-zones slight-freezing operation) performed after the all-zones thawing operation have different contents.

The zone slight-freezing operation is executed after the zone thawing operation. This operation is an operation that heats a thawed food in the thawing zone DZ by the heating unit <NUM> so that the temperature thereof is maintained at the slight-freezing temperature while the temperature in the freezing/thawing chamber 12b is maintained at the freezing preservation temperature. As a result, foods in the non-thawing zone NDZ are maintained at the freezing preservation temperature in the same manner as in the normal operation while the frozen food in the thawing zone DZ is maintained at the slight-freezing temperature.

The all-zones slight-freezing operation is executed after the all-zones thawing operation. This operation is an operation that maintains the temperature in the freezing/thawing chamber 12b at the slight-freezing temperature with the heating unit <NUM> stopped. As a result, the thawed food in the freezing/thawing chamber 12b is maintained at the slight-freezing temperature.

To execute the zone and all-zones slight-freezing operations, a thawed food detecting unit is needed that detects, after the completion of thawing, whether or not a thawed food is present in the freezing/thawing chamber 12b.

In the case of the present embodiment, the presence of a thawed food is detected using the above-described reflectance. That is, the reflected wave detecting circuit <NUM> detecting a reflected wave and the control unit <NUM> calculating the reflectance based on the detected reflected wave function as the thawed food detecting unit.

Specifically, as described in the quenching operation, when a food to be frozen from now on is placed in the thawing zone DZ, the reflectance drops beyond the first threshold value R1. From the opposite point of view, the reflectance increases beyond the first threshold value R1 when the thawed food is removed from the thawing zone DZ. Accordingly, if the reflectance rises beyond the first threshold value R1, it can be determined that the thawed food thawed by the zone thawing operation has been removed from the thawing zone DZ. Or, it can be determined that the food thawed by the all-zones thawing operation has been removed from the thawing zone D and the non-thawing zone NDZ.

When the presence of the thawed food is detected in the freezing/thawing chamber 12b after the completion of thawing, the zone or all-zones slight-freezing operation is executed. If the presence of the food is not detected, the normal operation is executed.

As an alternative, the presence of the thawed food may be detected by a door sensor <NUM> that detects opening and closing of the door (door part 46b of the drawer <NUM>) of the freezing/thawing chamber 12b, as shown in <FIG>.

The user needs to open the door to remove the thawed food from the freezing/thawing chamber 12b. Therefore, if the door sensor <NUM> does not detect opening of the door after thawing is completed, it can be determined that the thawed food is present in the freezing/thawing chamber 12b.

Further details of the zone slight-freezing operation and the all-zones slight-freezing operation will be described using a flowchart shown in <FIG>.

As shown in <FIG>, first, when the zone (all-zones) thawing operation terminates, the control unit <NUM> starts the zone (all-zones) slight-freezing operation at step S100.

At step S110, the control unit <NUM> determines whether or not a food is present in the freezing/thawing chamber 12b. If present, the process proceeds to step S120. If not, the process proceeds to step S140.

At step S120, the control unit <NUM> determines whether or not the food detected at step S110 is a thawed food. This is because the food detected at step S110 may be a food contained in the freezing/thawing chamber 12b to be frozen from now on. However, if the food detected at step S110 is a food to be frozen from now on, the door of the freezing/thawing chamber 12b is opened by the user after thawing is completed. That is, the door sensor <NUM> detects opening of the door after thawing is completed. Accordingly, if the door sensor <NUM> does not detect opening of the door, it is determined that the food detected at step S110 is a thawed food, allowing the process to proceed to step S130. If not, it is determined that the food detected at step S110 is a food to be frozen from now on, allowing the process to proceed to step S160 where the zone (all-zones) slight-freezing operation is terminated, to start the quenching operation at step S170 that follows.

If determined as the thawed food at step S120, the control unit <NUM> determines at step S130 whether or not a predetermined period of time has elapsed from the completion of thawing. This is because the quality of thawed foods deteriorates when it is preserved in a slightly frozen state for a long period of time. In the case of the all-zones thawing operation, the predetermined period of time is <NUM> days for example. In the case of the zone thawing operation, frost occurs more easily as compared with the all-zones thawing operation, so the predetermined period of time is <NUM> days that is shorter than in the all-zones thawing operation. If the predetermined period of time has elapsed from the completion of thawing, the process proceeds to step S140 to terminate the zone (all-zones) slight-freezing operation, to thereafter start the normal operation at step S150 that follows. If the predetermined period of time has not elapsed, the process returns to step S110.

As described above, according to the present embodiment, it is possible, in the refrigerator including the freezing/thawing chamber capable of freezing and thawing foods, to thaw foods in the freezing/thawing chamber without moving foods other than the foods to be thawed from the freezing/thawing chamber.

Hereinabove, the present invention has been described while referring to the above-described embodiment, but the present invention is not limited to the above-described embodiment. The present invention is limited by the appended claims.

Further, in the case of the above-described embodiment, as shown in <FIG>, the containing chamber of the heating module <NUM> functions as the freezing/thawing chamber 12b capable of freezing and thawing by introducing cold air. However, the embodiment of the present invention is not limited thereto. The heating module may not introduce cold air into its containment chamber, i.e., it may be dedicated to thawing. Then, the heating module <NUM> may be used not only for freezing and thawing and but also for cooling and heating foods as a temperature control. That is, the containing chamber of the heating module <NUM> may be the cooling/heating chamber.

As above, the embodiment has been described as an exemplification of the technique in the present disclosure. To that end, the accompanying drawings and detailed description have been provided. Therefore, the components described in the accompanying drawings and the detailed description may include not only components essential for solving the problem but also components not essential for solving the problem to exemplify the technique. Accordingly, immediately from the fact that those non-essential components are described in the accompanying drawings and the detailed description, those non-essential components should not be recognized as being essential.

Moreover, since the above-described embodiment is for exemplifying the technique in the present disclosure, various changes, replacements, additions, omissions, etc. can be made within the scope of the claims.

Claim 1:
A refrigerator (<NUM>) having a cooling/heating chamber (12b) capable of cooling and heating foods,
the cooling/heating chamber (12b) being divided into a heating zone (DZ) that is a space where foods to be heated are placed, and a non-heating zone (NDZ) that is a space continuous with the heating zone where foods not to be heated are placed, the refrigerator (<NUM>) comprising:
a heating module (<NUM>) incorporated in the main body of the refrigerator (<NUM>), the heating module (<NUM>) having a rectangular parallelepiped shape and being a double-walled structure including an inner case (<NUM>) and a shield case (<NUM>) containing the inner case (<NUM>), the inner case (<NUM>) defining the cooling/heating chamber (12b),
the heating module (<NUM>) including a heating unit (<NUM>) having:
an oscillation electrode (<NUM>) arranged on a ceiling part of the heating zone (DZ),
a counter electrode (<NUM>) arranged on a bottom part of the heating zone (DZ) so as to face the oscillation electrode (<NUM>) in a top-bottom direction, and
an oscillating unit (<NUM>) that applies an AC voltage to between the oscillation electrode (<NUM>) and the counter electrode (<NUM>) during execution of a zone heating operation.