[Technical Field]
[0001] The present invention relates to refrigerators in which lighting devices are provided.
[Background Art]
[0002] Typically, for refrigerators, interior lights using white light emitting diodes (LEDs) are proposed these days in addition to the interior lights using conventional incandescent lights or electric light bulbs.

[0003] As a refrigerator including a conventional lighting device, there is a refrigerator including a plurality of white LEDs mounted on a single board that is provided on a top face of inside of the refrigerator to illuminate the inside of the refrigerator (for example, see patent literature (PTL) 1).

[0004]
FIG. 10 is a perspective view of a lighting device of a conventional refrigerator described in PTL 1.

[0005] As shown in FIG. 10, the lighting device includes a mounting board 101, white LEDs 102, and a heat-insulating board 104, and is provided inside the refrigerator.

[0006] The mounting board 101 is formed in a tabular shape, has a circuit pattern (not shown) on one surface or both surfaces. An epoxy resin type board or an insulated metal board which has a good thermal conductivity is used as the mounting board 101.

[0007] Each of the white LEDs 102 is formed in a shell shape, excites phosphor materials using blue light from a GaN-based blue LED to provide white light, and has two current terminals 103 through which currents are provided.

[0008] The heat-insulating board 104 is made of resin, such as urethane, is formed in a tabular shape, has a plurality of through holes, and is provided between the mounting board 101 and the white LEDs 102. Here, the current terminals 103 are inserted to the through holes in the heat-insulating board 104, and are soldered to a circuit pattern on the mounting board 101 to mount the white LEDs 102. A plurality of the white LEDs 102 is arranged on the mounting board 101.

[0009] Note that, when the white LEDs 102 emit small amount of heat, the heat-insulating board 104 may be eliminated.

[0010] The following describes operations of the refrigerator which uses, as the lighting device, the white LEDs configured as described above.

[0011] First, when the door of the refrigerator is closed, the white LEDs 102 are not powered, and thus the inside of the refrigerator is not illuminated.

[0012] Then, when the door is opened, the door is determined to be open using a mechanical switch or an electronic switch, such as a hall IC, a direct voltage is applied to the mounting board 101, a forward current flows to the white LED 102 through the current terminals 103, and white light is emitted. The inside of the refrigerator is thus illuminated. [Citation List] [Patent Literature]

[0013] [PTL 1] Japanese Unexamined Patent Application Publication No. 11-159953

[Summary of Invention]

[Technical Problem]

[0014] However, the above-described conventional structure illuminates the inside of the refrigerator with a maximum brightness all the time and thus is not energy efficient. Furthermore, the storage item cannot be illuminated with brightness suitable for the environment where the refrigerator is installed.

[0015] The refrigerator is usually used in an environment where a room light of a kitchen is lit, and thus the inside of the refrigerator can be seen even when the brightness of the interior light is low. However, the light needs to be set to be bright, considering a situation in which the inside of the refrigerator is hard to see by a user. In other words, when the outside (surrounding environment) of the refrigerator is bright, power is consumed wastefully.

[0016] Furthermore, the light source emits larger amount of heat when the brightness increases, causing a problems of deterioration in cooling ability of refrigerator and a decrease in operating life of the light.

[0017] Furthermore, when a user opens a door of the refrigerator when the outside of the refrigerator is dark and a bright interior light is lit instantly, the eyes of a user can be affected by the glare. Thus, it is sometimes desirable that the brightness be reduced.

[0018] The present invention is conceived to solve the above-describe conventional problems and has as an object to provide a refrigerator including a lighting device that can adjust the brightness of the interior light according to the illumination of outside of the refrigerator.

[Solution to Problem]

[0019] In order to solve the conventional problems, a refrigerator according to the present invention is a refrigerator which includes: a main body including a plurality of storage compartments which are partitioned by a heat-insulating wall and a heat-insulating door; an interior light which illuminates inside of a storage compartment among the storage compartments; an outside illumination detection unit configured to detect illumination of outside of the main body; a door open and closed detection unit configured to detect whether the heat-insulating door is open or closed; and a control unit configured to adjust brightness of the interior light according to the detected illumination, when the door open and closed detection unit detects that the heat-insulating -door is open, wherein the control unit is configured to change the brightness or a lighting pattern of the interior light when the heat-insulating door is open, the detected illumination being detected by the outside illumination detection unit.

[0020] With this, a light that has high energy efficiency, has long operating life, and is comfortable for the eyes of a user is realized.

[Advantageous Effects of Invention]

[0021] The present invention makes it possible to realize the light that has high energy efficiency, has long operating life, and is comfortable for the eyes of a user, and thus can provide a refrigerator which saves energy and has higher usability.

[Brief Description of Drawings]

[0022]

[FIG. 1] FIG. 1 is a front view of a refrigerator according to Embodiment 1 of the present invention.

[FIG. 2] FIG. 2 is a cross-sectional view of the refrigerator, according to Embodiment 1 of the present invention, taken along line A - A of FIG. 1.

[FIG. 3] FIG. 3 is a control block diagram of the refrigerator according to Embodiment 1 of the present invention.

[FIG. 4] FIG. 4 is a top view of the refrigerator, according to Embodiment 1 of the present invention, installed at a corner of a kitchen.

[FIG. 5] FIG. 5 is a timing diagram showing an output to an interior light of the refrigerator according to Embodiment 1 of the present invention.

[FIG. 6] FIG. 6 is a timing diagram showing a change in output to an interior light of the refrigerator according to Embodiment 1 of the present invention.

[FIG. 7] FIG. 7 is a diagram showing a brightness-varying circuit of the interior light of the refrigerator according to Embodiment 1.

[FIG. 8] FIG. 8 is a cross-sectional view of a refrigerator according to Embodiment 2 of the present invention.

[FIG. 9] FIG. 9 is a control block diagram of the refrigerator according to Embodiment 2 of the present invention.

[FIG. 10] FIG. 10 is a perspective view of a lighting device of a conventional refrigerator described in PTL1.

[Description of Embodiments]

[0023] According to a first aspect of the present invention, a refrigerator includes: a main body including a plurality of storage compartments which are partitioned by a heat-insulating wall and a heat-insulating door; an interior light which illuminates inside of a storage compartment; an outside illumination detection unit which is provided on the heat-insulating door of a topmost storage compartment among the storage compartments and detects illumination of outside of the main body; a door open and closed detection unit configured to detect whether the heat-insulating door is open or closed; and a control unit configured to adjust brightness of the interior light according to detected illumination, when the door open and closed detection unit detects that the heat-insulating door is open, wherein the control unit is configured to change the brightness or a lighting pattern of the interior light when the heat-insulating door is continuously open, the detected illumination being detected by the outside illumination detection unit. With this, it is possible to illuminate the inside of the refrigerator with an optimal brightness according to the brightness of surroundings of a user. Thus, it is possible to realize the light which can save energy, has a long operating life, and is comfortable for the eyes of users.

[0024] According to a second aspect of the present invention, the brightness of the interior light is increased when the detected illumination is determined to be high illumination using the outside illumination detection unit, and the brightness of the interior light is decreased when the detected illumination is determined to be low illumination using the outside illumination detection unit. With this, it is possible to reduce the brightness of the interior light so that a user is not affected by the glare when the outside is dark.

[0025] According to a third aspect of the present invention, the brightness of the interior light is decreased when the detected illumination is determined to be high illumination or low illumination using the outside illumination detection unit, and the brightness of the interior light is increased when the detected illumination is determined to be neither high illumination nor low illumination using the outside illumination detection unit. With this, it is possible to (i) save energy by reducing the brightness of the interior light when the outside is bright, (ii) reduce the brightness of the interior light so that the user is not affected by the glare when the outside is dark, and (iii) increase the brightness so that storage items can be seen easily when the outside is neither bright nor dark._ t: _

[0026] According to a fourth aspect of the present invention, a light emitting diode is used as a light source of the interior light. With this, it is possible to provide a light which drives at a low voltage and generates less amount of heat. Thus, it is possible to simplify a driving circuit, improve controllability, and reduce the amount of heat generated by the light source.

[0027] According to a fifth aspect of the present invention, the control unit is configured to adjust the brightness of the interior light by pulse control. With this, power can be adjusted by controlling duty, which makes it possible to change the brightness of the interior light with a simple control.

[0028] According to a sixth aspect of the present invention, the control unit is configured to adjust the brightness of the interior light by current control. Using a technique, such as switching of current limiting resistors, flickering of light generated due to pulse control at low brightness can be removed.

[0029] According to a seventh aspect of the present invention, the control unit is configured to adjust the brightness of the interior light by voltage control. With this, it becomes possible to reduce both the power supply voltage and the current flowing to the light, and thus the energy is further saved.

[0030] According to an eighth aspect of the present invention, the interior light includes a plurality of light sources, and the control unit is configured to adjust the brightness, by changing a total number of light sources turned on among the light sources. With this, the power of the power source which is turned off is zero, and thus the energy can be further saved.

[0031] According to a ninth aspect of the present invention, the storage compartment includes a storage item detection unit, and the control unit is configured to adjust the brightness of the interior light according to the detection by the outside illumination detection unit and the detection by the storage item detection unit. With this, it is possible to prevent the occurrence of the case in which a storage item is hard to see due to the shade or the absorption of light by storage items.

[0032] Hereinafter, embodiments of the present invention shall be described with reference to the Drawings. Note that the present invention is not limited by such embodiments.

[0033] (Embodiment 1) FIG. 1 is a front view of a refrigerator according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the refrigerator according to Embodiment 1 taken along line A - A of FIG. 1. FIG. 3 is a control block diagram of the refrigerator according to Embodiment 1. FIG. 4 is a top view of the refrigerator, according to Embodiment 1, installed at a corner of a kitchen.

[0034] In FIG. 1, FIG. 2, and FIG. 3, the main body of a refrigerator 1 includes a heat-insulating wall 2 and heat-insulating doors 3a and 3b, and thus the inside of the refrigerator is insulated from the outside. The refrigerator 1 includes, in a storage compartment 4, storage shelves 5 for storing storage items in order.

[0035] The heat-insulating door 3b includes a display unit 6 which displays an operating status, a setting, or the like of the refrigerator. Furthermore, the display unit 6 has an illumination sensor 7 which is provided as an outside illumination detection unit.

[0036] The illumination sensor 7 as the outside illumination detection unit is provided on the heat-insulating door of a storage compartment on the top-most portion among the storage compartments of the refrigerator 1, and is provided at a height close to the position of the eyes of a user. Thus, brightness equivalent to the illumination perceived by the user can be detected.

[0037] In the case of a typical refrigerator which has five storage compartments as shown in the drawing and has a storage capacity of approximately 400 L to 600 L, the height close to the eyes of the user is between the vicinity of 1/2 in a height direction of the topmost storage compartment and approximately 1/5 from the uppermost end towards the bottom of the topmost storage compartment.

[0038] Furthermore, in the storage compartment 4, an interior light 8 is built into the interior walls on the left and right as seen from the front of the refrigerator 1. The interior light 8 includes a plurality of white LEDs 9a to 9d which are arranged along a vertical direction, and is provided so that light is irradiated from the front side of the storage compartment 4 toward the back.

[0039] As described, a light source that uses white LEDs can smoothly respond to a varied current. Furthermore, such a light source can be driven at a low voltage. Thus, the heat generated by the interior light 8 can be kept low. As described, the light source that uses white LEDs is expected to simplify a driving circuit, improve controllability, and reduce the amount of heat generated by the light source.

[0040] Furthermore, a door open and closed detection unit 10 is provided on the rim of the front opening of the storage compartment 4 to detect whether the heat-insulating doors 3a and 3b are open or closed.

[0041] A control unit 11 turns the interior light 8 on, when it is detected that the heat-insulating door 3a or 3b is open. At this time, the control unit 11 adjusts the brightness of the interior light 8 based on the illumination detected by the illumination sensor 7.

[0042] When the refrigerator 1 is installed at a corner of a kitchen, the surface on which the illumination sensor 7 is provided can come close to the wall as shown in FIG. 4, when the heat-insulating door 3b is open. At this time, it is hard for the external light to incident on the illumination sensor 7 because the front of the illumination sensor 7 is blocked by the wall of the kitchen. Thus, erroneous detection occurs and the illumination is detected to be lower than the actual outside illumination. In view of this, the control unit 11 stores, at any time, the illumination detected by the illumination sensor 7, and determines the brightness of the interior light, based on the illumination detected immediately before or immediately after it is detected that the heat-insulating door 3b is open.

[0043] The Table 1 shows an example of the relationship between (i) the detected illumination, that is, illumination detected by the illumination sensor 7 and (ii) brightness of the interior light 8.

[0044] [Table 1]

[0045] Table 1 shows three types of pattern of change in brightness of the interior light 8 for the detected illumination L by the illumination sensor 7. The brightness of the interior light 8 is described in a relative value, where 100% represents the maximum brightness. [0046]
In Table 1, the determination according to pattern 1 is as follows. Specifically, it is determined dark when the outside illumination detected by the illumination sensor 7 is less than or equal to a first reference outside illumination (set to 15 lux in this embodiment) that is one of preset reference outside illuminations. In this case, the brightness of the interior light 8 is set to 100%. Furthermore, it is determined comparatively dark when the illumination sensor 7 detects the outside illumination less than or equal to a second reference outside illumination (set to 40 lux in this embodiment). In this case, the brightness of the interior light 8 is set to 75%. When the outside illumination is comparatively low, storage items inside the refrigerator can be seen sufficiently even when the brightness of the interior light 8 is comparatively low (approximately 75%). Furthermore, it is determined bright when the illumination sensor 7 detects an outside illumination exceeding the second reference outside illumination (40 lux). In this case, the brightness of the interior light 8 is set to 50%. When the outside illumination is bright, the external light also illuminates the storage items inside the refrigerator, and thus the storage items inside the refrigerator can be seen sufficiently. As described, since the refrigerator is often used when the outside is bright, brightness of the interior light 8 can be reduced. Thus, it is possible to reduce the power consumption.

[0047] Thus, the objective of pattern 1 is to provide a user with lighting for finding a storage item inside the refrigerator, with the sum of brightness which reaches the inside of the refrigerator from outside and the brightness of the interior light 8.

[0048] According to pattern 2, it is determined dark when the illumination sensor 7 detects the outside illumination less than or equal to a first reference outside illumination (15 lux). In this case, the brightness is set to 50% for a user who feels that the interior light 8 is too bright. Furthermore, it is determined comparatively dark when the outside illumination less than or equal to a second reference outside illumination (40 lux) is detected. In this case, the brightness is set to 75% with which it is not too bright and the storage items are easy to see. Furthermore, it is determined bright when the illumination sensor 7 detects an outside illumination exceeding the second reference outside illumination (40 lux). In this case, the brightness is set to 100% with which it can be perceived that the interior light 8 is lit. As described, not only it is possible to reduce the brightness of the interior light 8 and reduce the power consumption, but also it is possible to give consideration to the glare observed by the user and the ease in seeing the storage items.

[0049] As described, pattern 2 focuses on a sensual element of a user so that the user is not visually affected by the glare. In other words, the storage items are illuminated with low illumination when it is dark. Thus, an objective is to provide functions that serve as a universal design which is comfortable for the eyes and does not cause physical discomfort.

[0050] According to pattern 3, it is determined dark when the illumination sensor 7 detects the outside illumination less than or equal to the first reference outside illumination (15 lux). In this case, the brightness is set to 50% for a user who feels that the interior light 8 is too bright. Furthermore, it is determined comparatively dark when an outside illumination less than or equal to the second reference outside illumination (40 lux) is detected. In this case, the brightness is set to 100% which is brightness with which storage items are most easy to see for a user who is not affected by glare. Furthermore, it is determined bright when the detected outside illumination exceeds the second reference outside illumination (40 lux). In this case, the brightness of the interior light 8 is set to 50% because the external light also illuminates the storage items inside the refrigerator. Thus, pattern 3 has advantages of patterns 1 and 2.

[0051] As described, the brightness of the interior light 8 is set to 50% when the outside is bright, that is, when it is expected that the refrigerator is most often opened and closed. Thus, it is possible to further save energy. Thus, when a pattern, such as pattern 3, that enables saving of energy in the case where the frequency of use is expected to be high is selected, lighting or display that would be associated with saving of energy may be provided in a position, such as on an outer door of the refrigerator or on a main body, easily catching the sight of a user.

[0052] It may be configured so that users can set patterns 1 to 3 through an operation unit (not shown) according to their preference.

[0053] In this case, a user has a wider range of options. For example, a user who has no visual problems and prefers the light to be constantly bright selects pattern 1, a household including a user, such as a senior or a child, for whom it is desirable that visual load is not encountered selects pattern 2, and a household which is more conscious of energy saving selects pattern 3. Thus, it is possible to provide a refrigerator which is more convenient to use, and is capable of saving energy.

[0054] Furthermore, the detected illumination L (outside illumination) and the relative brightness of the interior light 8 in Table 1 is not limited to the values described in the table, but should be set to optimal values according to structure of a refrigerator.

[0055] Next, a brightness adjustment unit of the interior light 8 is described.

[0056] FIG. 5 is a timing diagram showing an output to an interior light of the refrigerator according to Embodiment 1 of the present invention. FIG. 6 is a timing diagram showing a change in output to an interior light of the refrigerator according to Embodiment 1 of the present invention.

[0057] For example, the brightness of the interior light 8 is adjusted by adjusting effective power supplied to the white LEDs 9a to 9d, by controlling duty of an output voltage. As shown in FIG. 5, a duty ratio T1/T2 is changed, according to the detected value of the outside illumination by the illumination sensor 7, where Tl represents output pulse width and T2 represents a cycle of a pulse. T1/T2 is set to a level at which a user do not perceive the flickering of the white LEDs 9a to 9d.

[0058] Furthermore, when the interior light 8 is lit, if the interior light 8 is lit with 100% brightness instantly, a user is affected by glare and feels discomfort. In view of this, the brightness may be gradually changed (in particular, increased) until predetermined brightness is reached.

[0059] FIG. 6 shows that the duty ratio right after the light is turned on is T3/T4 = 10% (step 1). After this, till 100% is reached, the duty ratio is gradually increased at predetermined intervals of time, such as T5/T6 = 40% (step 2), and T7/T8 = 70% (step 3). With this, a light is lit in a mild manner. The duty ratio is changed in three stages in this example. However, the brightness can be changed more smoothly, by increasing the stages of change so that the duty ratio is changed in finer increments.

[0060] Note that, when the interior light 8 is lit for some time, the eyes of users get used to the brightness, and thus the storage items can be seen sufficiently even when the brightness is slightly reduced. Thus, the power consumption may be reduced by reducing the duty ratio gradually, when a predetermined period of time is passed after the interior light 8 is turned on.

[0061] FIG. 7 is a diagram showing a brightness-varying circuit of the interior light of the refrigerator according to Embodiment 1.

[0062] FIG. 7 shows a circuit as an example of a brightness adjustment unit of the interior light 8. With this, a supply current for the interior light 8 may be changed among II to 13, by switching the switches SW 1 to SW 3. The supply currents II to 13 are determined by resistors Rl to R3, each having a different resistance value.

[0063] Furthermore, the brightness of the interior light 8 may also be adjusted by, for example, lighting two LEDs that is half the LEDs, or lighting three LEDs that is 3/4 of the LEDs among the white LEDs 9a to 9d shown in FIG. 2.

[0064] As described, the refrigerator according to this embodiment includes: the interior light 8 which illuminates the inside of the storage compartment 4 that is partitioned by the heat-insulating wall 2, and the heat-insulating doors 3a and 3b; the illumination sensor 7 which is provided on the heat-insulating door of the storage compartment on the top-most portion among the storage compartments and detects the outside illumination of the refrigerator 1; the door open and closed detection unit 10 which detects whether the heat-insulating doors 3a and 3b are open or closed; and the control unit 11 which adjusts the brightness of the interior light 8, according to the detected illumination by the illumination sensor 7 which is detected immediately before or after the door open and closed detection unit 10 detects that the heat-insulating door 3a or 3b is open. With this, it is possible to illuminate the inside of the refrigerator with an optimal brightness according to the brightness of surroundings of a user. Thus, it is possible to realize the light which has high energy efficiency, has a long operating life, and is comfortable for the eyes of users.

[0065] Furthermore, according to this embodiment, the light emitting diodes 9a to 9d are used as light sources of the interior light 8. With this, it is possible to provide a light which drives at a low voltage and generates less amount of heat. Thus, it is possible to simplify the driving circuit, improve controllability, and reduce the amount of heat generated by the light sources.

[0066] Furthermore, according to this embodiment, the control unit 11 changes brightness or a lighting pattern of the interior light 8 depending on the time - 13- during which the heat-insulating door 3a or 3b is continuously open. With this, " it is possible to have control to gradually increase or decrease the brightness of the interior light considering the adaptability of the eyes of a user on brightness, and thus a light that is comfortable for the eyes of users can be realized.

[0067] (Embodiment 2) FIG. 8 is a cross-sectional view of a refrigerator according to Embodiment 2 of the present invention. FIG. 9 is a control block diagram of a refrigerator according to Embodiment 2. Here, components identical to the components in Embodiment 1 are assigned the same reference signs and the detailed description thereof is omitted.

[0068] In FIG. 8 and FIG. 9, a storage item detection unit 12 is provided in a storage compartment 4. The storage item detection unit 12 detects a position or volume of the storage item, and includes an illumination sensor 7 which is not an outside illumination detection unit. The storage item detection unit 12 is realized by detecting, in the refrigerator using the illumination sensor 7, brightness attenuated due to blocking of light by the storage items. Other than this, the storage items can be detected using a pressure sensor.

[0069] In Embodiment 1, the brightness of the interior light 8 is adjusted, based only on the detected illumination by the illumination sensor 7. However, it is possible that the inside of the refrigerator is not adequately illuminated due to the shadows of storage items when there are many storage items in the storage compartment 4. Thus, in addition to the brightness of the outside of the refrigerator, it is preferable that the positions and the volume of the storage items be considered in adjusting the brightness of the interior light 8.

[0070]Table 2 shows a brightness correction value of the interior light on stored volume.

[0071] [Table 2]

[0072] The brightness of the interior light according to Table 2 is obtained by adding a correction value in Table 2 to the value shown in table 1. For example, the brightness is set to -20% when the storage item detection unit 12 detects that the stored volume is small, because it is easy for the light to reach the corners inside of the refrigerators. Furthermore, a correction is not made when it is detected that the stored volume is comparatively large. The brightness is set to +20% when it is detected that the stored volume is large, because it becomes hard for the light to reach the inside of the refrigerator.

[0073] As described, the refrigerator according to this embodiment includes the storage item detection unit 12 in the storage compartment 4. With this, storage items inside the refrigerator are also detected in addition to the illumination outside of the refrigerator to illuminate the inside of the refrigerator with the brightness required by a user. Thus, it is possible to realize a light which is more convenient to use.

[Industrial Applicability]

[0074] As described, a refrigerator according to the present invention can be naturally implemented when applied as a lighting device of a household or industrial refrigerator, and can also be applied to a wide range of equipment, such as item storage apparatus including a door, to which a light is provided.

[Reference Signs List] [0075]

1 Refrigerator

2 Heat-insulating wall

3a, 3b Heat-insulating door

4 Storage compartment

5 Storage shelf
6 Display unit

7 Illumination sensor

8 Interior light

9a, 9b, 9c, 9d White LED

10 Door open and closed detection unit

11 Control unit

12 Storage item detection unit

[CLAIMS]

[Claim 1] A refrigerator comprising: a main body including a plurality of storage compartments which are partitioned by a heat-insulating wall and a heat-insulating door; an interior light which illuminates inside of a storage compartment among the storage compartments; an outside illumination detection unit configured to detect illumination of outside of the main body; a door open and closed detection unit configured to detect whether the heat-insulating door is open or closed; and a control unit configured to adjust brightness of the interior light according to detected illumination, when the door open and closed detection unit detects that the heat-insulating door is open, wherein the control unit is configured to change the brightness or a lighting pattern of the interior light when the heat-insulating door is open, the detected illumination being detected by the outside illumination detection unit.

[Claim 2] The refrigerator according to Claim 1, wherein, when the control unit determines that the detected illumination is lower than a reference outside illumination, the control unit is configured to set the brightness of the interior light to be lower than the brightness of the interior light when the control unit determines that the detected illumination is higher than the reference outside illumination, the detected illumination being detected by the outside illumination detection unit, and the reference outside illumination being preset illumination.

[Claim 3] The refrigerator according to Claim 1, wherein, when the control unit determines that the detected illumination is neither lower than a first reference outside illumination nor higher than a second reference outside illumination, the control unit is configured to set the brightness of the interior light to be higher than (i) the brightness of the interior light when the detected illumination is lower than the first reference outside illumination and (ii) the brightness of the interior light when the detected illumination is higher than the second reference outside illumination, the detected illumination being detected by the outside illumination detection unit, the first reference outside illumination being preset illumination lower than illumination of the second reference outside illumination, and the second reference outside illumination being preset illumination.

[Claim 4] The refrigerator according to any one of Claims 1 to 3, wherein the interior light includes a light emitting diode as a light source.

[Claim 5] The refrigerator according to any one of Claims 1 to 4, wherein the control unit is configured to adjust the brightness of the interior light by pulse control.

[Claim 6] The refrigerator according to any one of Claims 1 to 4, wherein the control unit is configured to adjust the brightness of the interior light by current control.

[Claim 7] The refrigerator according to any one of Claims 1 to 4, wherein the control unit is configured to adjust the brightness of the interior light by voltage control.

[Claim 8] The refrigerator according to any one of Claims 1 to 4, wherein the interior light includes a plurality of light sources, and the control unit is configured to adjust the brightness, by changing a total number of light sources turned on among the light sources.

[Claim 9] The refrigerator according to any one of Claims 1 to 8, wherein the storage compartment includes a storage item detection unit, and the control unit is configured to adjust the brightness of the interior light according to the detection by the outside illumination detection unit and the detection by the storage item detection unit.