Judgment device, ice maker, and electronic equipment

Abstract

The present invention provides a determination device, ice maker, and electronic equipment capable of distinguishing between ice and water. [Solution] The determination device comprises an optical distance sensor that detects the distance to the target, and a processing unit that determines whether the target is ice or water based on the distance.

Description

Technical Field

[0001] The present disclosure relates to a determination device, an ice maker, and an electronic device.

Background Art

[0002] Patent Document 1 discloses an ice maker. In this ice maker, water supply is performed to the ice-making water tank from when it is detected that the water level of the ice-making water tank has become the low water level until it is detected that the water level of the ice-making water tank has become the high water level. Further, the ice-making water supplied from the ice-making water tank is frozen to make ice. Further, the ice-making amount is estimated based on the number of detections when it is detected that the water level of the ice-making water tank has become the high water level or the number of detections when it is detected that the water level of the ice-making water tank has become the low water level (paragraphs 0005 and 0007).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an ice maker, there may be a case where it is required to distinguish ice and water from each other.

[0005] One aspect of the present disclosure has been made in view of this problem. One aspect of the present disclosure aims to provide, for example, a determination device, an ice maker, and an electronic device that can distinguish ice and water from each other.

Means for Solving the Problems

[0006] The determination device according to the first aspect of the present disclosure includes an optical distance sensor that detects the distance to an object, and a processing unit that determines whether the object is ice or water based on the distance.

[0007] An ice maker according to a second aspect of the present disclosure comprises a cooler for cooling a stored material, a determination device according to a first aspect of the present disclosure, and a controller for controlling the cooler based on the result of the determination.

[0008] An electronic device according to a third aspect of the present disclosure comprises a determination device according to a first aspect of the present disclosure. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram schematically illustrates the state in which the ice maker of the first embodiment is determined to be water by a determination device provided in the ice maker. [Figure 2] This diagram schematically illustrates the state in which the ice maker of the first embodiment is determined to be ice by a determination device provided in the ice maker. [Figure 3] This is a block diagram of a determination device provided in the ice maker of the first embodiment. [Figure 4] This is a schematic cross-sectional view illustrating an optical distance sensor provided in the ice maker of the first embodiment. [Figure 5] This is a schematic perspective view illustrating the lens and Si substrate provided in the ice maker of the first embodiment. [Figure 6] This is a schematic cross-sectional view illustrating the first experimental apparatus. [Figure 7] This graph shows the relationship between distance values ​​and light intensity values ​​output by the optical distance sensor installed in the first experimental apparatus. [Figure 8] This is a schematic cross-sectional view illustrating the second experimental apparatus. [Figure 9] This graph shows how the distance and light intensity values ​​output by the optical distance sensor installed in the second experimental apparatus change with the horizontal position of the optical distance sensor. [Figure 10] This is a schematic cross-sectional view illustrating the third experimental apparatus. [Figure 11] This graph shows the relationship between light intensity and distance values ​​output by the third experimental apparatus. [Figure 12]It is a flowchart showing the flow of processing performed by the determination device provided in the ice maker of the first embodiment. [Figure 13] It is a flowchart showing the flow of processing performed by the determination device provided in the ice maker of the second embodiment. [Figure 14] It is a cross-sectional view schematically showing a state where the detection direction of the optical distance sensor provided in the fourth experimental device is downward in the vertical direction and the object provided in the fourth experimental device is water. [Figure 15] It is a cross-sectional view schematically showing a state where the detection direction of the optical distance sensor provided in the fourth experimental device is downward in the vertical direction and the object provided in the fourth experimental device is opaque ice. [Figure 16] It is a cross-sectional view schematically showing a state where the detection direction of the optical distance sensor provided in the fourth experimental device is a direction inclined from the downward vertical direction and the object provided in the fourth experimental device is water. [Figure 17] It is a cross-sectional view schematically showing a state where the detection direction of the optical distance sensor provided in the fourth experimental device is a direction inclined from the downward vertical direction and the object provided in the fourth experimental device is opaque ice. [Figure 18] It is a graph showing the change of the light quantity value output by the optical distance sensor provided in the fourth experimental device according to the inclination angle from the downward vertical direction of the detection direction of the optical distance sensor. [Figure 19] It is a graph showing the change of parameter A according to the inclination angle from the downward vertical direction of the detection direction of the optical distance sensor when the determination object is opaque ice. [Figure 20] It is a graph showing the relationship when vertical determination is performed between the light quantity value and the distance value output by the optical distance sensor provided in the ice maker of the third embodiment. [Figure 21] It is a graph showing the relationship when inclination determination is performed between the light quantity value and the distance value output by the optical distance sensor provided in the ice maker of the third embodiment. [Figure 22] It is a diagram schematically showing an ice maker according to a third embodiment. [Figure 23] It is a flowchart showing the flow of processing performed by a determination device provided in an ice maker according to a third embodiment. [Figure 24] It is a flowchart showing the flow of creation of a pre-database used for processing performed by a determination device provided in an ice maker according to a third embodiment. [Figure 25] It is a block diagram of a determination device provided in an ice maker according to a fourth embodiment. [Figure 26] It is a top view schematically showing a state in which the use area of an optical distance sensor provided in an ice maker according to a fourth embodiment is the entire light receiving area. [Figure 27] It is a top view schematically showing a state in which the use area of an optical distance sensor provided in an ice maker according to a fourth embodiment is a part of the light receiving area. [Figure 28] It is a cross-sectional view schematically showing an optical distance sensor provided in an ice maker according to a fifth embodiment and a stored substance stored in a water storage tank provided in the ice maker. [Figure 29] It is a distance value map obtained by mapping a plurality of distance values output by an optical distance sensor provided in an ice maker according to a fifth embodiment. [Figure 30] It is a distance value map obtained by mapping a plurality of distance values output by an optical distance sensor provided in an ice maker according to a fifth embodiment. [Figure 31] It is a graph showing the distribution of a plurality of distance values output by an optical distance sensor provided in an ice maker according to a fifth embodiment.

Embodiments for Carrying out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Regarding the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0011] 1 First Embodiment 1.1 Ice Maker Figure 1 schematically illustrates the state in which the ice maker of the first embodiment is determined to be water by the determination device provided in the ice maker. Figure 2 schematically illustrates the state in which the ice maker of the first embodiment is determined to be ice by the determination device provided in the ice maker.

[0012] The ice maker 1 of the first embodiment, as illustrated in Figures 1 and 2, determines whether the object 101 is ice 111 or water 112, and proceeds with ice making based on the result of the determination.

[0013] As shown in Figures 1 and 2, the ice maker 1 comprises a water storage tank 121, a cooler 122, a determination device 123, and a controller 124.

[0014] The water tank 121 stores the stored material 131. As ice making progresses, the stored material 131 changes from water 112 to ice 111 and then to ice 111 via a mixture of water 112 and other substances 141.

[0015] The cooler 122 cools the reservoir 131. As a result, the cooler 122 converts the water 112 contained in the reservoir 131 into ice 111.

[0016] As shown in Figures 1 and 2, the cooler 122 includes a cooling rod 151. The cooler 122 includes a refrigeration cycle (not shown). The lower part of the cooling rod 151 is located inside the water tank 121 and is immersed in the reservoir 131 stored in the water tank 121. The upper part of the cooling rod 151 is located outside the water tank 121 and is connected to the refrigeration cycle. As a result, the cooling rod 151 is cooled by the refrigeration cycle and cools the reservoir 131 into which it is immersed. Thus, the change from water 112 to ice 111 occurs near the cooling rod 151.

[0017] The cooler 122 may have a structure different from the structure shown in Figures 1 and 2.

[0018] The determination device 123 determines whether the object 101 is ice 111 or water 112. The object 101 is located vertically below the determination device 123. The horizontal position 161 where the determination is made is separated from the horizontal position where the cooling rod 151 is placed. The object 101 is part of the stored material 131.

[0019] The controller 124 controls the cooler 122 based on the result of the determination. For example, if the controller 124 determines that the target 101 is water 112, it causes the cooler 122 to cool the stored material 131, but if the controller 124 determines that the target 101 is ice 111, it does not cause the cooler 122 to cool the stored material 131.

[0020] The controller 124 comprises a microcontroller and auxiliary circuits. The microcontroller comprises a processor and memory. The processor executes a program stored in memory to operate the microcontroller and auxiliary circuits as the controller 124. All or part of the processing performed by the microcontroller may be performed by dedicated electronic circuits.

[0021] The ice maker 1 is an example of an electronic device equipped with a determination device 123. Other electronic devices besides the ice maker 1 may also be equipped with a determination device 123.

[0022] 1.2 Modules Figure 3 is a block diagram of a determination device provided in the ice maker of the first embodiment.

[0023] As shown in Figure 3, the determination device 123 includes a module 171.

[0024] Module 171 emits a first light (emitted light) 181, receives a second light (reflected light) 182 generated when the object 101 reflects the first light 181, detects the distance to the object 101 based on the time from the emission of the first light 181 to the receipt of the second light 182, detects the intensity of the second light 182, and outputs a detection result 191. Based on the detection result 191, Module 171 determines whether the object 101 is ice 111 or water 112, and outputs a determination result 192.

[0025] As shown in Figure 3, module 171 comprises an optical distance sensor 201, a determination unit 202, a first storage unit 203, and an output unit 204.

[0026] The optical distance sensor 201 is a time-of-flight (ToF) type optical distance sensor. Therefore, the optical distance sensor 201 emits a first light 181 and receives a second light 182, and detects the distance to the object 101 based on the time from the emission of the first light 181 to the receipt of the second light 182. The optical distance sensor 201 also detects the intensity of the second light 182. The optical distance sensor 201 stores the detection result 191 and outputs the stored detection result 191.

[0027] The determination unit 202 reads the stored detection result 191, determines whether the object 101 is ice 111 or water 112 based on the read detection result 191, and outputs the determination result 192. The determination unit 202 determines whether the object 101 is ice 111 or water 112 based on the distance to the object 101 included in the detection result 191. The determination unit 202 is an MCU equipped with a processor, memory, and peripheral circuits. The processor executes a program stored in memory to cause the determination unit 202 to perform the necessary processing. All or part of the processing performed by the determination unit 202 may be performed by dedicated electronic circuits.

[0028] The first storage unit 203 stores the output detection result 191 and judgment result 192, and outputs the stored detection result 191 and judgment result 192. The detection result 191 and judgment result 192 output by the first storage unit 203 are output from module 171. The first storage unit 203 includes memory and the like.

[0029] The output unit 204 outputs the result of the judgment, 192.

[0030] 1.3 Optical distance sensor As shown in Figure 3, the optical distance sensor 201 comprises a light-emitting element 211, a light-receiving element 212, a control element 213, an MCU 214, and a second memory unit 215.

[0031] The light-emitting element 211 emits the first light 181. The light-emitting element 211 is a vertical-cavity surface-emitting laser (VCSEL). The light-emitting element 211 may be a light-emitting element other than a VCSEL.

[0032] The photodetector 212 receives the second light 182 and outputs a signal 221 corresponding to the received second light 182. The photodetector 212 is a single-photon avalanche diode (SPAD) array. The photodetector 212 may be a photodetector other than a SPAD array.

[0033] The control element 213 performs light emission control 223 to control the emission of the first light 181 by the light-emitting element 211, and light reception control 224 to control the reception of the second light 182 by the light-receiving element 212, according to the given control instruction 222. The control element 213 makes the first light 181 pulsed light.

[0034] The MCU 214 reads the setting 225 and gives a control instruction 222 to the control element 213 according to the read setting 225. Based on the given control instruction 222 and the output signal 221, the MCU 214 determines the time from the emission of the first light 181 to the receipt of the second light 182, and determines the distance to the object 101 based on the determined time. Based on the given control instruction 222 and the output signal 221, the MCU 214 determines the light intensity of the second light 182. The MCU 214 outputs a detection result 191 indicating the determined distance and light intensity. The output detection result 191 includes a distance value indicating the distance to the object 101 and a light intensity value indicating the light intensity of the second light 182.

[0035] The second memory unit 215 stores the output detection result 191 and outputs the stored detection result 191. The detection result 191 output by the second memory unit 215 is output from the optical distance sensor 201. The second memory unit 215 stores the settings 225 to be read. The second memory unit 215 includes memory and the like.

[0036] In module 171, a determination unit 202, which is externally attached to the optical distance sensor 201, constitutes a processing unit that determines whether the object 101 is ice 111 or water 112 based on the distance to the object 101. However, if the MCU 214 built into the optical distance sensor 201 has sufficient capacity, the MCU 214 may constitute the processing unit. If the MCU 214 constitutes the processing unit, the determination unit 202 may be omitted.

[0037] 1.4 Structure of an optical distance sensor Figure 4 is a schematic cross-sectional view illustrating an optical distance sensor provided in the ice maker of the first embodiment.

[0038] As shown in Figure 4, the optical distance sensor 201 comprises a package 231, a light-emitting element 211, a lens 232, an optical filter 233, an optical filter 234, a light-shielding resin 235, and an integrated circuit (IC) 236. The IC 236 comprises a light-receiving element 212 and a light-receiving element 216. The IC 236 also comprises a control element 213, which is not shown in Figure 4.

[0039] Package 231 has an internal space 231a, a first opening window 231b, and a second opening window 231c. The internal space 231a houses an optical filter 233, an optical filter 234, a light-shielding resin 235, and an IC 236. The second opening window 231c houses a lens 232. The first opening window 231b leads from the internal space 231a to the outside of package 231. The second opening window 231c leads from the outside of package 231 to the internal space 231a.

[0040] The light-emitting element 211 emits light including a first light 181 and a third light 183. The first light 181 travels from the light-emitting element 211 to the object 101 via the internal space 231a and the first opening window 231b of the package 231. The third light 183 travels via the internal space 231a to the light-receiving element 216.

[0041] Object 101 reflects the first light 181 and generates reflected light. The second light 182 contained in the generated reflected light travels from object 101 through the second opening window 231c and internal space 231a of package 231 to the light-receiving element 212.

[0042] The lens 232 transmits the second light 182 passing through the second aperture window 231c of the package 231, and focuses the transmitted second light 182 onto the light-receiving element 212.

[0043] The optical filter 233 is placed on IC 236 and on the photodetector 212 provided on IC 236. The optical filter 233 selectively transmits light having the wavelength of the second light 182 and wavelengths close to that wavelength. The optical filter 233 is made of glass. The optical filter 233 may be made of a material other than glass.

[0044] The light-receiving element 212 receives the second light 182 that has passed through the optical filter 233 and outputs a signal 221 corresponding to the received second light 182. The light-receiving element 212 is a SPAD array. The light-receiving element 212 may be a light-receiving element other than a SPAD array.

[0045] The optical filter 234 is placed on IC 236 and on the photodetector 216 provided on IC 236. The optical filter 234 selectively transmits light having the wavelength of the third light 183 and wavelengths close to that wavelength. The optical filter 234 is made of glass. The optical filter 234 may be made of a material other than glass.

[0046] The light-receiving element 216 receives the third light 183 that has passed through the optical filter 234 and outputs a signal corresponding to the received third light 183. The light-receiving element 216 is a SPAD array. The light-receiving element 212 may be a light-receiving element other than a SPAD array.

[0047] The light-shielding resin 235 is placed on IC 236 and between optical filter 233 and optical filter 234. The light-shielding resin 235 blocks the third light 183, preventing it from reaching the photodetector 212, and blocks the second light 182, preventing it from reaching the photodetector 216.

[0048] The MCU214 determines the distance from the signal 221 output by the photodetector 212 and the signal output by the photodetector 216 to the target 101, as well as the light intensity of the second light 182.

[0049] 1.5 SPAD Array Figure 5 is a schematic perspective view illustrating the lens and Si substrate provided in the ice maker of the first embodiment.

[0050] As shown in Figure 5, the optical distance sensor 201 comprises a lens 232 and a Si substrate 241. The Si substrate 241 comprises a light-receiving element 212 and a circuit 251. The light-receiving element 212 comprises a plurality of SPADs 261. The Si substrate 241 is mounted on IC 236.

[0051] The light-receiving element 212 has a light-receiving area 271. The light-receiving area 271 is perpendicular to the optical axis of the lens 232 and is the area that receives the second light 182 that has passed through the lens 232. Multiple SPADs 261 are arranged in a matrix in the light-receiving area 271. Each SPAD 261 included in the multiple SPADs 261 receives a light ray arriving from a direction corresponding to the position in which each SPAD 261 is placed and outputs a signal corresponding to the received light ray. The light-receiving area 271 includes a usable area 272 used to receive the second light 182. In the first embodiment, the usable area 272 is the entire light-receiving area 271 and does not change. The MCU 214 detects the distance to the object 101 and the amount of light of the second light 182 based on the signals 221 output by the multiple SPADs 261 placed in the usable area 272.

[0052] Circuit 251 includes a VCSEL drive circuit and a signal processing circuit. The VCSEL drive circuit drives the light-emitting element 211. The signal processing circuit processes the signal 221 output by the photodetector 212 and the signal output by the photodetector 216.

[0053] 1.6 Detection direction of optical distance sensor Each SPAD261 receives light rays arriving from a direction corresponding to its position and outputs a signal corresponding to the received light ray. The MCU214 also detects the distance to the target 101 and the amount of light from the second light 182 based on the signals 221 output by the multiple SPAD261s positioned in the usable area 272 close to the optical axis of the lens 232. Therefore, the detection direction D in which the optical distance sensor 201 detects the distance to the target 101 is a direction close to the direction extending from the optical distance sensor 201 along the optical axis of the lens 232.

[0054] The optical distance sensor 201 is positioned such that its detection direction D is vertically downward. This allows the optical distance sensor 201 to detect the distance to the object 101 located vertically downward.

[0055] If the object 101 is water 112 and the detection direction D of the optical distance sensor 201 is vertically downward, then the detection direction D of the optical distance sensor 201 is perpendicular to the surface of the water 112. Therefore, the second light 182 includes a specular reflection component and a scattered reflection component.

[0056] 1.7 Changes in distance and light intensity Figure 6 is a schematic cross-sectional view illustrating the first experimental apparatus. Figure 7 is a graph showing the relationship between distance values ​​and light intensity values ​​output by an optical distance sensor installed in the first experimental apparatus. In the graph of Figure 7, distance values ​​are plotted on the horizontal axis and light intensity values ​​are plotted on the vertical axis.

[0057] The first experimental apparatus 281 shown in Figure 6 comprises a mixture 141 of ice 111 and water 112, and an optical distance sensor 201. The optical distance sensor 201 is positioned vertically above the mixture 141 and at a horizontal position 291 where the water surface of water 112 is located, or at a horizontal position 292 where the ice surface of ice 111 is located. The vertical distance from the optical distance sensor 201 to the water surface of water 112 is 27 mm. The vertical distance from the water surface of water 112 to the bottom of the container holding the mixture 141 is 30 mm. The optical distance sensor 201 outputs a distance value indicating the distance to the object 101 and a light intensity value indicating the light intensity of the second light 182.

[0058] As shown in Figure 7, when the optical distance sensor 201 was positioned at horizontal position 291 and vertically above the surface of the water 112, the output distance value was approximately 27 mm, close to the actual distance of 27 mm, and the output light intensity value was approximately 600,000 counts. When the optical distance sensor 201 was positioned at horizontal position 292 and vertically above the surface of the ice 111, the output distance value was approximately 60 mm, larger than the actual distance, and the output light intensity value was approximately 100,000 counts.

[0059] Figure 8 is a schematic cross-sectional view illustrating the second experimental apparatus. Figure 9 is a graph showing the change in distance and light intensity values ​​output by an optical distance sensor installed in the second experimental apparatus, depending on the horizontal position of the optical distance sensor. In the graph of Figure 9, the horizontal position is plotted on the horizontal axis, and the distance and light intensity values ​​are plotted on the vertical axis.

[0060] The second experimental apparatus 301, shown in Figure 8, comprises a mixture 141 of ice 111 and water 112, and an optical distance sensor 201. The optical distance sensor 201 is positioned vertically above the mixture 141 and is moved horizontally from a horizontal position where the surface of water 112 is located to a horizontal position where the surface of ice 111 is located. The optical distance sensor 201 outputs a distance value indicating the distance to the object 101 and a light intensity value indicating the light intensity of the second light 182.

[0061] As shown in Figure 9, while the optical distance sensor 201 was moving within the horizontal range 311 where the surface of water 112 was located and moving vertically above the surface of water 112, the output distance value was approximately 27 mm, close to the actual distance of 27 mm, and the output light intensity value was approximately 600,000 counts, showing a large fluctuation. While the optical distance sensor 201 was moving horizontally within the horizontal range 312 where the surface of ice 111 was located and moving vertically above the surface of ice 111, the output distance value was approximately 60 mm, larger than the actual distance, and the output light intensity value was approximately 100,000 counts, showing no large fluctuation.

[0062] Figure 10 is a schematic cross-sectional view illustrating the third experimental apparatus. Figure 11 is a graph showing the relationship between light intensity values ​​and distance values ​​output by an optical distance sensor installed in the third experimental apparatus. In the graph of Figure 11, light intensity values ​​are plotted on the horizontal axis and distance values ​​on the vertical axis.

[0063] The third experimental apparatus 321 shown in Figure 10 comprises a mixture 141 of ice 111 and water 112, an optical distance sensor 201, and a container 331. The optical distance sensor 201 is positioned vertically above the mixture 141 and vertically above the surface of the water 112 or the ice surface of the ice 111. The container 331 contains the mixture 141. The distance from the optical distance sensor 201 to the ice surface of the ice 111 is 27 mm, the distance from the optical distance sensor 201 to the surface of the water 112 is approximately 30 mm, the thickness of the ice 111 is approximately 3 mm and is non-uniform, and the distance from the optical distance sensor 201 to the bottom of the container that stores the mixture 141 is 57 mm. The optical distance sensor 201 outputs a distance value indicating the distance to the object 101 and a light intensity value indicating the light intensity of the second light 182.

[0064] As shown in Figure 11, when the optical distance sensor 201 is positioned vertically above the surface of the water 112, the output distance value is approximately 30 mm, close to the actual distance of 30 mm, and the output light intensity value is approximately 700,000 counts. When the optical distance sensor 201 is positioned vertically above the surface of the ice 111, the output distance value is approximately 57 mm, greater than the actual distance of 27 mm, and the output light intensity value is approximately 100,000 counts. Therefore, if the distance value and light intensity value are within the range 341, for example, having a distance value of 35 mm or more and a light intensity value of 400,000 counts or more, it can be determined that the object 101 is ice 111, and if the distance value and light intensity value are outside the range 341, it can be determined that the object 101 is not ice 111.

[0065] From these experimental results, it can be seen that when object 101 is water 112, the output distance value is approximately the same as the actual distance to object 101. On the other hand, when object 101 is ice 111, it can be seen that the output distance value is greater than the actual distance to object 101.

[0066] Furthermore, when the target 101 is water 112, it can be observed that the output light intensity value is relatively large, and the variation in the output light intensity value is relatively large. On the other hand, when the target 101 is ice 111, the output light intensity value is relatively small, less than 1 / 5 of the output light intensity value when the target 101 is water 112, and the variation in the output light intensity value is relatively small.

[0067] When target 101 is water 112, the light intensity value is high, which is thought to be because the specular reflection component in the second light 182 is large. When target 101 is water 112, the relatively large variation in light intensity values ​​is thought to be due to the effect of surface ripples in water 112. When target 101 is ice 111, the distance value is longer than the actual distance to target 101, which is thought to be because the penetration distance of the first light 181 into target 101 is longer.

[0068] Based on these considerations, the distance value output when the object 101 is water 112 is stored, and if the difference obtained by subtracting the stored distance value from the distance value output at the time of determination becomes greater than a threshold, it can be determined that the object 101 has changed from water 112 to ice 111. The threshold varies depending on the performance of the optical distance sensor 201, the measurement system, etc., but for example, it is 30 mm.

[0069] Furthermore, if the standard deviation σ of the p output light intensity values ​​is less than the set standard deviation, and the quotient obtained by dividing the light intensity value output on the Nth time by the light intensity value output on the N+pth time is greater than or equal to the set quotient, then it can be determined that the object 101 has changed from water 112 to ice 111. The value p varies depending on the performance of the optical distance sensor 201, the measurement system, etc., but for example, it is 20. The set standard deviation varies depending on the performance of the optical distance sensor 201, the measurement system, etc., but for example, it is 50000. The set quotient varies depending on the performance of the optical distance sensor 201, the measurement system, etc., but for example, it is 5.

[0070] 1.8 Processing Flow Figure 12 is a flowchart showing the processing flow performed by the determination device provided in the ice maker of the first embodiment.

[0071] The determination device 123 performs steps S101 to S109 shown in Figure 12.

[0072] In step S101, the determination unit 202 activates the optical distance sensor 201. As a result, the optical distance sensor 201 starts repeatedly updating the distance value and light intensity value stored in the second memory unit 215 to the latest distance value and light intensity value.

[0073] In the subsequent step S102, the determination unit 202 reads the distance value from the second storage unit 215 and sets the read distance value as the baseline value. The baseline value indicates the reference distance. Step S102 is performed before the cooler 122 starts cooling the reservoir 131 in step S103. Therefore, the baseline value indicates the distance detected by the optical distance sensor 201 when the target 101 is water 112, and indicates the water level of the water 112.

[0074] In the following step S103, the controller 124 causes the cooler 122 to begin cooling the reservoir 131. This initiates the transformation of the water 112 contained in the reservoir 131 into ice 111. This initiates the growth of the ice 111.

[0075] In the following step S104, the determination unit 202 reads the distance value from the second memory unit 215.

[0076] In the subsequent step S105, the determination unit 202 determines whether the difference obtained by subtracting the baseline value from the distance value read in step S104 is greater than a threshold. This difference indicates the increase in the distance value from the baseline value and the increase in distance from the reference distance. If the determination unit 202 determines that the difference is greater than the threshold, it executes step S106. If the determination unit 202 determines that the difference is less than the threshold, it executes step S107. The threshold is set to a value slightly smaller than the difference between the distance value output by the optical distance sensor 201 when the object 101 is water 112 and the distance value output by the optical distance sensor 201 when the object 101 is ice 111. For example, as shown in the graph in Figure 7, if the former distance value is approximately 27 mm and the latter distance value is approximately 60 mm, the threshold is set to 30 mm, which is slightly smaller than the difference of 33 mm between 27 mm and 60 mm.

[0077] In step S106, the determination unit 202 determines that the target 101 is ice 111.

[0078] In step S107, the determination unit 202 determines whether the difference between the baseline value and the distance value included in the read detection result 191 is smaller than the set difference. If the determination unit 202 determines that the difference is smaller than the set difference, it executes step S108. If the determination unit 202 determines that the difference is larger than the set difference, it executes step S109. The set difference is, for example, ±5 mm.

[0079] In step S108, the determination unit 202 determines that the target 101 is water 112.

[0080] In step S109, the determination unit 202 performs an error determination.

[0081] In steps S102 and S103, the determination unit 202 uses the distance detected by the optical distance sensor 201 as the reference distance if the target 101 is water 112. The determination unit 202 obtains the water level of the water 112 from the distance detected by the optical distance sensor 201 if the target 101 is water 112.

[0082] In steps S104 to S109, the determination unit 202 non-contactually determines whether the object 101 is ice 111 or water 112 based on the detected distance. The determination unit 202 determines that the object 101 is ice 111 if the difference obtained by subtracting the reference distance from the detected distance is greater than a threshold, and determines that the object 101 is water 112 if the difference obtained by subtracting the reference distance from the detected distance is less than a threshold. The determination unit 202 makes an error determination if it is not possible to determine whether the object 101 is ice 111 or water 112. Situations in which it is not possible to determine whether the object 101 is ice 111 or water 112 may occur due to dust adhering to the optical distance sensor 201, etc.

[0083] 2. Second Embodiment The following describes the differences between the second embodiment and the first embodiment. For aspects not described, the same configuration as that used in the first embodiment is used in the second embodiment.

[0084] In the second embodiment, the determination unit 202 determines whether the object 101 is ice 111 or water 112 based on the distance to the object 101 and the light intensity of the second light 182.

[0085] Figure 13 is a flowchart showing the processing flow performed by the determination device provided in the ice maker of the second embodiment.

[0086] In the second embodiment, the determination device 123 performs steps S201 to S210 shown in Figure 13.

[0087] In step S201, the determination unit 202 activates the optical distance sensor 201. As a result, the optical distance sensor 201 starts repeatedly updating the distance value and light intensity value stored in the second memory unit 215 to the latest distance value and light intensity value.

[0088] In the subsequent step S202, the determination unit 202 reads the distance value and light intensity value from the second storage unit 215 and sets the read distance value and light intensity value as the baseline values ​​for the distance value and light intensity value, respectively. The baseline value for the distance value indicates the reference distance. The baseline value for the light intensity value indicates the reference light intensity. Step S202 is performed before the cooler 122 starts cooling the reservoir 131 in step S203. Therefore, the baseline value for the distance value indicates the distance detected by the optical distance sensor 201 when the target 101 is water 112, and indicates the water level of the water 112. The baseline value for the light intensity value indicates the light intensity detected by the optical distance sensor 201 when the target 101 is water 112.

[0089] In the following step S203, the controller 124 causes the cooler 122 to begin cooling the reservoir 131. This initiates the transformation of the water 112 contained in the reservoir 131 into ice 111. This initiates the growth of the ice 111.

[0090] In the following step S204, the determination unit 202 reads the distance value and the light intensity value from the second memory unit 215.

[0091] In the subsequent step S205, the determination unit 202 determines whether the difference obtained by subtracting the baseline value of the distance value from the distance value read in step S204 is greater than a threshold. This difference indicates the increase in the distance value from the baseline value and the increase in distance from the reference distance. If the determination unit 202 determines that the difference is greater than the threshold, it executes step S206. If the determination unit 202 determines that the difference is less than the threshold, it executes step S208. The threshold is set to a value slightly smaller than the difference between the distance value output by the optical distance sensor 201 when the object 101 is water 112 and the distance value output by the optical distance sensor 201 when the object 101 is ice 111. For example, as shown in the graph in Figure 7, if the former distance value is approximately 27 mm and the latter distance value is approximately 60 mm, the threshold is set to 30 mm, which is slightly smaller than the difference of 33 mm between 27 mm and 60 mm.

[0092] In step S206, the determination unit 202 determines whether the decrease in the light intensity value read from the baseline value is greater than the set decrease. If the determination unit 202 determines that the decrease is greater than the set decrease, it executes step S207. If the determination unit 202 determines that the decrease is less than the set decrease, it executes step S208. The set decrease is, for example, a decrease to 1 / 3 of the baseline value of the light intensity.

[0093] In step S207, the determination unit 202 determines that the target 101 is ice 111.

[0094] In step S208, the determination unit 202 determines whether the difference between the baseline distance value and the read distance value is less than the set difference. If the determination unit 202 determines that the difference is less than the set difference, it executes step S209. If the determination unit 202 determines that the difference is greater than the set difference, it executes step S210. The set difference is, for example, ±5 mm.

[0095] In step S209, the determination unit 202 determines that the target 101 is water 112.

[0096] In step S210, the determination unit 202 performs an error determination.

[0097] In steps S202 and S203, the determination unit 202 determines that if the target 101 is water 112, the distance and light intensity detected by the optical distance sensor 201 are the reference distance and reference light intensity, respectively.

[0098] In steps S201 to S210, the determination unit 202 non-contactually determines whether the object 101 is ice 111 or water 112 based on the detected distance and light intensity. The determination unit 202 determines that the object 101 is ice 111 if the difference obtained by subtracting the reference distance from the detected distance is greater than a threshold and the decrease in the detected light intensity from the reference light intensity is greater than a set decrease, and determines that the object 101 is water 112 if the difference between the reference distance and the detected distance is less than a set difference.

[0099] 3. Third Embodiment The differences between the third embodiment and the first embodiment will be explained below. For aspects not explained, the same configuration as that used in the first embodiment will be used in the third embodiment.

[0100] Figure 14 is a schematic cross-sectional view illustrating the fourth experimental apparatus in a state where the detection direction of the optical distance sensor provided in the fourth experimental apparatus is vertically downward, and the object provided in the fourth experimental apparatus is water. Figure 15 is a schematic cross-sectional view illustrating the fourth experimental apparatus in a state where the detection direction of the optical distance sensor provided in the fourth experimental apparatus is vertically downward, and the object provided in the fourth experimental apparatus is opaque ice. Figure 16 is a schematic cross-sectional view illustrating the fourth experimental apparatus in a state where the detection direction of the optical distance sensor provided in the fourth experimental apparatus is inclined from vertically downward, and the object provided in the fourth experimental apparatus is water. Figure 17 is a schematic cross-sectional view illustrating the fourth experimental apparatus in a state where the detection direction of the optical distance sensor provided in the fourth experimental apparatus is inclined from vertically downward, and the object provided in the fourth experimental apparatus is opaque ice.

[0101] The fourth experimental apparatus 351, illustrated in Figures 14 to 17, includes an optical distance sensor 201 and a target 101.

[0102] As shown in Figures 14 and 16, when the object 101 is water 112, the upper surface of the object 101 is the water surface of the water 112. Therefore, the object 101 specularly reflects the first light 181 and generates reflected light consisting of a specular reflection component 361.

[0103] As shown in Figures 15 and 17, when the object 101 is opaque ice 371, the upper surface of the object 101 is the ice surface of the opaque ice 371. Therefore, the object 101 specularly and scatters the first light 181 to generate reflected light consisting of a specular reflection component 361 and a scatter reflection component 362.

[0104] As shown in Figure 14, when the detection direction D of the optical distance sensor 201 is vertically downward, the object 101 is water 112, and the detection direction D of the optical distance sensor 201 forms a 90° angle with the surface of the water 112, the second light 182 includes a specular reflection component 361. As shown in Figure 15, when the detection direction D of the optical distance sensor 201 is vertically downward, the object 101 is opaque ice 371, and the detection direction D of the optical distance sensor 201 forms a 90° angle with the surface of the opaque ice 371, the second light 182 includes a specular reflection component 361 and a scattered reflection component 362. However, because the light intensity of the specular reflection component 361 is large, the scattered reflection component 362 is obscured by the specular reflection component 361. Therefore, when the detection direction D of the optical distance sensor 201 is vertically downward, it is difficult to distinguish between the second light 182 when the object 101 is water 112 and the second light 182 when the object 101 is opaque ice 371. Consequently, when the detection direction D of the optical distance sensor 201 is vertically downward, it is difficult to determine from the light intensity of the second light 182 whether the object 101 is opaque ice 371 or water 112.

[0105] As shown in Figure 16, when the detection direction D of the optical distance sensor 201 is inclined from the vertical downward direction, the object 101 is water 112, and the detection direction D of the optical distance sensor 201 is at an angle other than 90° to the surface of the water 112, the second light 182 becomes significantly weaker. As shown in Figure 17, when the detection direction D of the optical distance sensor 201 is inclined from the vertical downward direction, the object 101 is opaque ice 371, and the detection direction D of the optical distance sensor 201 is at an angle other than 90° to the ice of the opaque ice 371, the second light 182 does not contain a specular reflection component 361, but contains a scattered reflection component 362. Therefore, when the detection direction D of the optical distance sensor 201 is inclined from the vertical downward direction, it is easy to distinguish between the second light 182 when the object 101 is water 112 and the second light 182 when the object 101 is opaque ice 371. Therefore, if the detection direction D of the optical distance sensor 201 is inclined downward from the vertical direction, it is easy to determine whether the object 101 is opaque ice 371 or water 112 from the light intensity of the second light 182.

[0106] Figure 18 is a graph showing the change in light intensity value output by an optical distance sensor installed in the fourth experimental apparatus, with respect to the tilt angle from the vertical downward direction of the detection direction of the optical distance sensor. In the graph of Figure 18, the tilt angle is plotted on the horizontal axis, and the light intensity value is plotted on the vertical axis.

[0107] As shown in Figure 18, when the inclination angle of the detection direction D of the optical distance sensor 201 from the vertical downward direction is less than 15°, the light intensity value output by the optical distance sensor 201 when the object 101 is water 112 and the light intensity value output by the optical distance sensor 201 when the object 101 is opaque ice 371 are approximately the same. In contrast, when the inclination angle of the detection direction D of the optical distance sensor 201 from the vertical downward direction is 15° or more, the light intensity value output by the optical distance sensor 201 when the object 101 is water 112 and the light intensity value output by the optical distance sensor 201 when the object 101 is opaque ice 371 are significantly different.

[0108] Here, we consider the following parameter A, which is expressed using the light intensity value SIGw output by the optical distance sensor 201 when the object 101 is water 112, the light intensity value SIGx output by the optical distance sensor 201 when the object 101 is an object to be judged, and the light intensity value SIGp output by the optical distance sensor 201 when the object 101 is a blank sheet of paper with 0% transparency.

[0109] A = (SIGx - SIGw) / (SIGp - SIGw)

[0110] Parameter A, as described above, indicates the transparency of the object being evaluated. Parameter A decreases as the transparency of the object increases.

[0111] The molecule (SIGx-SIGw) generally represents the difference between the amount of light from the specular reflection component generated by the water 112 and the sum of the amount of light from the specular reflection component and the scattered reflection component generated by the object being detected, when the detection direction D of the optical distance sensor 201 is vertically downward. It has a magnitude close to 0 regardless of the type of object being detected. However, when the detection direction D of the optical distance sensor 201 is inclined from vertically downward, the molecule (SIGx-SIGw) generally represents the amount of light from the scattered reflection component generated by the object being detected. When the object being detected is water 112, it has a magnitude close to 0, but when the object being detected is opaque ice 371, it has a magnitude significantly larger than 0. Therefore, when the detection direction D of the optical distance sensor 201 is vertically downward, the molecule (SIGx-SIGw) does not strongly reflect the type of object being detected. However, the molecule (SIGx-SIGw) strongly reflects the type of object being detected when the detection direction D of the optical distance sensor 201 is tilted from the vertical downward direction. As a result, by setting the detection direction D of the optical distance sensor 201 to tilted from the vertical downward direction, parameter A can be used as a parameter indicating the type of object being detected.

[0112] The numerator (SIGx - SIGw) is divided by the denominator (SIGp - SIGw). This allows parameter A to be used as a parameter indicating the transparency of the object being judged, with white paper having 0% transparency and mainly generating scattered reflection components as the standard. White paper was used as the standard because white paper with a reflectivity of 88% is also used in the shipping inspection of the optical distance sensor 201, and it is a common standard in the technical field of optical distance sensors 201.

[0113] Figure 19 is a graph showing the change in parameter A due to the tilt angle from the vertical downward direction of the detection direction D of the optical distance sensor 201, when the object to be judged is opaque ice 371. In the graph of Figure 19, the tilt angle is plotted on the horizontal axis and parameter A is plotted on the vertical axis.

[0114] As shown in Figure 19, parameter A has a magnitude close to 0 (-20% to +20%) when the tilt angle of the detection direction D of the optical distance sensor 201 from the vertical downward is less than 15°, and a magnitude significantly greater than 0 (approximately 65%) when the tilt angle of the detection direction D of the optical distance sensor 201 from the vertical downward is 15° or more.

[0115] Based on these considerations, in the third embodiment, the determination unit 202 performs a vertical determination to determine whether the object 101 is transparent ice 372 when the detection direction D of the optical distance sensor 201 is set to the vertical downward direction, and performs an inclination determination to determine whether the object 101 is opaque ice 371 or water 112 when the detection direction D of the optical distance sensor 201 is set to a direction inclined from the vertical downward direction. When the detection direction D of the optical distance sensor 201 is set to a direction inclined from the vertical downward direction, the inclination angle of the detection direction D of the optical distance sensor 201 from the vertical downward direction is 15° or more. The determination unit 202 determines whether the object 101 is opaque ice 371 or water 112 based on a parameter indicating the transparency of the object 101, such as parameter A.

[0116] Figure 20 is a graph showing the relationship between the light intensity value and distance value output by the optical distance sensor installed in the ice maker of the third embodiment when vertical determination is performed. Figure 21 is a graph showing the relationship between the light intensity value and distance value output by the optical distance sensor installed in the ice maker of the third embodiment when tilt determination is performed. In the graphs of Figures 20 and 21, the light intensity value is plotted on the horizontal axis and the distance value is plotted on the vertical axis.

[0117] As shown in Figure 20, when a vertical determination is made, the light intensity and distance values ​​when object 101 is transparent ice 372 differ significantly from the light intensity and distance values ​​when object 101 is opaque ice 371 or water 112. Therefore, it is determined whether object 101 is transparent ice 372 or not based on the light intensity and distance values. For example, if the light intensity and distance values ​​fall within range 381, which has a distance value of 35 mm or more and a light intensity value of 400,000 counts or more, object 101 is determined to be transparent ice 372. If the light intensity and distance values ​​do not fall within range 381, object 101 is determined not to be transparent ice 372. However, the light intensity and distance values ​​when object 101 is opaque ice 371 do not differ significantly from the light intensity and distance values ​​when object 101 is water 112. Therefore, it is not possible to determine whether object 101 is opaque ice 371 or water 112 based on the light intensity and distance values.

[0118] As shown in Figure 21, when tilt determination is performed, the light intensity value when object 101 is opaque ice 371 differs significantly from the light intensity value when object 101 is water 112. Therefore, it is determined whether object 101 is opaque ice 371 or water 112 based on the light intensity value. For example, if the light intensity value falls within range 382, ​​which has a light intensity value of 1,000,000 counts or more, object 101 is determined to be opaque ice 371. On the other hand, if the light intensity value does not fall within range 382, ​​object 101 is determined not to be opaque ice 371.

[0119] Therefore, the determination device 123 determines whether the object 101 is transparent ice 372, opaque ice 371, or water 112 by performing both vertical and inclination determination.

[0120] Figure 22 is a schematic diagram illustrating an ice maker according to the third embodiment.

[0121] The ice maker 3 of the third embodiment shown in Figure 22 determines whether the target 101 is clear ice 372, opaque ice 371, or water 112.

[0122] As shown in Figure 22, the ice maker 3 includes a modification unit 401.

[0123] The modification unit 401 changes the detection direction D of the optical distance sensor 201 to either the vertical downward direction or a direction inclined from the vertical downward direction.

[0124] As shown in Figure 22, the modification unit 401 includes a posture modification unit 411.

[0125] The attitude changing unit 411 changes the attitude of the optical distance sensor 201. The changing unit 401 changes the detection direction D of the optical distance sensor 201 as a result of the attitude changing unit 411 changing the attitude of the optical distance sensor 201.

[0126] Figure 23 is a flowchart showing the processing flow performed by the determination device provided in the ice maker of the third embodiment.

[0127] In the third embodiment, the determination device 123 performs steps S301 to S315 shown in Figure 23.

[0128] In S301, the determination unit 202 instructs the modification unit 401 to direct the detection direction D of the optical distance sensor 201 downward in the vertical direction.

[0129] In the following step S302, the determination unit 202 activates the optical distance sensor 201. As a result, the optical distance sensor 201 starts repeatedly updating the distance value and light intensity value stored in the second memory unit 215 to the latest distance value and light intensity value.

[0130] In the subsequent step 303, the determination unit 202 reads the distance value and light intensity value from the second storage unit 215, and sets the read distance value and light intensity value as the baseline values ​​for the distance value and light intensity value, respectively. The baseline value for the distance value indicates the reference distance. The baseline value for the light intensity value indicates the reference light intensity. Step S303 is performed before the cooler 122 starts cooling the reservoir 131 in step S304. Therefore, the baseline value for the distance value indicates the distance detected by the optical distance sensor 201 when the target 101 is water 112, and indicates the water level of the water 112. The baseline value for the light intensity value indicates the light intensity detected by the optical distance sensor 201 when the target 101 is water 112.

[0131] In the following step S304, the controller 124 causes the cooler 122 to begin cooling the reservoir 131. This initiates the transformation of the water 112 contained in the reservoir 131 into ice 111. This initiates the growth of the ice 111.

[0132] In the following step S305, the determination unit 202 reads the distance value and the light intensity value from the second memory unit 215.

[0133] In the subsequent step S306, the determination unit 202 determines whether the difference obtained by subtracting the baseline value of the distance value from the distance value read in step S305 is greater than a threshold. This difference indicates the increase in the distance value from the baseline value and the increase in distance from the reference distance. If the determination unit 202 determines that the difference is greater than a predetermined threshold, it executes step S307. If the determination unit 202 determines that the difference is less than the threshold, it executes step S309. The threshold is set to a value slightly smaller than the difference between the distance value output by the optical distance sensor 201 when the object 101 is water 112 and the distance value output by the optical distance sensor 201 when the object 101 is ice 111. For example, as shown in the graph in Figure 7, if the former distance value is approximately 27 mm and the latter distance value is approximately 60 mm, the threshold is set to 30 mm, which is slightly smaller than the difference of 33 mm between 27 mm and 60 mm.

[0134] In step S307, the determination unit 202 determines whether the decrease in the light intensity value read from the baseline value is greater than the set decrease. If the determination unit 202 determines that the decrease is greater than the set decrease, it executes step S308. If the determination unit 202 determines that the decrease is less than the set decrease, it executes step S309. The set decrease is, for example, a decrease to 1 / 3 of the baseline value of the light intensity.

[0135] In step S308, the determination unit 202 determines that the target 101 is transparent ice 372.

[0136] In step S309, the determination unit 202 determines whether the difference between the baseline distance value and the read distance value is less than the set difference. If the determination unit 202 determines that the difference is less than the set difference, it executes step S310. If the determination unit 202 determines that the difference is greater than the set difference, it executes step S315. The set difference is, for example, ±5 mm.

[0137] In step S310, the determination unit 202 instructs the modification unit 401 to tilt the detection direction D of the optical distance sensor 201 in a direction tilted by a set inclination angle from the vertical downward. The set inclination angle is, for example, 15°.

[0138] In the following step S311, the determination unit 202 reads the light intensity value from the second memory unit 215.

[0139] In the subsequent step S312, the determination unit 202 obtains parameter A from the read light intensity value and determines whether the obtained parameter A is greater than a set threshold. If the determination unit 202 determines that parameter A is greater than the set threshold, it executes step S313. If the determination unit 202 determines that parameter A is less than the set threshold, it executes step S314. The set threshold varies depending on the performance of the optical distance sensor 201, the measurement system, etc., but is, for example, 50%.

[0140] In step S313, the determination unit 202 determines that the target 101 is opaque ice 371.

[0141] In step S314, the determination unit 202 determines that the target 101 is water 112.

[0142] In step S315, the determination unit 202 performs an error determination.

[0143] In steps S301 to S315, the determination unit 202 non-contactually determines whether the object 101 is transparent ice 372, opaque ice 371, or water 112 based on the detected distance and light intensity. The determination unit 202 then determines whether the object 101 is transparent ice 372 based on the vertical distance and vertical light intensity detected by the optical distance sensor 201 when the detection direction D of the optical distance sensor 201 is vertically downward, and whether the object 101 is opaque ice 371 or water 112 based on the tilted light intensity detected by the optical distance sensor 201 when the detection direction D of the optical distance sensor 201 is tilted from vertically downward. The determination unit 202 then determines that the object 101 is opaque ice 371 if the tilted light intensity is greater than the set light intensity, and determines that the object 101 is water 112 if the tilted light intensity is less than the set light intensity. The set light intensity is determined by a threshold value compared with parameter A in step S312. The determination unit 202 obtains parameter A, which indicates the transparency of the object 101, from the light intensity at tilt, and determines whether the object 101 is opaque ice 371 or water 112 based on the obtained parameter A. Parameter A may be replaced with other parameters that indicate the transparency of the object 101.

[0144] As a result, the determination unit 202 can determine whether the target 101 is ice 111 or water 112, regardless of whether the ice 111 is transparent ice 372 or opaque ice 371.

[0145] Figure 24 is a flowchart showing the flow of creating a pre-database used for processing performed by the determination device provided in the ice maker of the third embodiment.

[0146] The pre-database is created after module 171 is installed in the ice maker 3, for example, when the ice maker 3 undergoes its final inspection. If the pre-database is created before module 171 is installed in the ice maker 3, it will be affected by lot-to-lot differences in optical distance sensors 201, variations in installation position, etc. In contrast, if the pre-database is created after module 171 is installed in the ice maker 3, it will not be affected by lot-to-lot differences in optical distance sensors 201, variations in installation position, etc. Therefore, the pre-database can be created in a state close to the actual operating condition of the ice maker 3, and the judgment device 123 can be calibrated.

[0147] When the pre-database is created, the target 101 is blank, and steps S321 to S324 shown in Figure 24 are executed.

[0148] In step S321, the determination unit 202 activates the optical distance sensor 201. As a result, the optical distance sensor 201 starts repeatedly updating the distance value and light intensity value stored in the second memory unit 215 to the latest distance value and light intensity value.

[0149] In step S322, the determination unit 202 instructs the modification unit 401 to tilt the detection direction D of the optical distance sensor 201 in a direction tilted by a set inclination angle from the vertical downward. The set inclination angle is, for example, 15°.

[0150] In the following step S323, the determination unit 202 reads the light intensity value from the second memory unit 215.

[0151] In the subsequent step S324, the determination unit 202 creates a pre-database from the read light intensity values. The created pre-database includes information to determine the formula for calculating parameter A.

[0152] 4. Fourth Embodiment The following describes the differences between the fourth embodiment and the third embodiment. For aspects not described, the fourth embodiment employs the same configuration as that used in the third embodiment.

[0153] Figure 25 is a block diagram of a determination device provided in the ice maker of the fourth embodiment.

[0154] In the fourth embodiment, as shown in Figure 25, the MCU 214 configures a usage area modification unit 421 that changes the usage area 272 used to receive the second light 182 so that the usage area 272 becomes the entirety of the light receiving area 271 or a part of the light receiving area 271.

[0155] In the fourth embodiment, as shown in Figure 25, the modification unit 401 includes a usage area modification unit 421. The modification unit 401 changes the detection direction D of the optical distance sensor 201 by having the usage area modification unit 421 modify the usage area 272.

[0156] Figure 26 is a schematic top view illustrating the optical distance sensor provided in the ice maker of the fourth embodiment, with the usable area encompassing the entire light-receiving area. Figure 27 is a schematic top view illustrating the optical distance sensor provided in the ice maker of the fourth embodiment, with the usable area encompassing only a portion of the light-receiving area. In Figures 26 and 27, the usable area is filled in.

[0157] As shown in Figure 26, when the usable area 272 encompasses the entire light-receiving area 271, the detection direction D of the optical distance sensor 201 becomes vertically downward. As shown in Figure 27, when the usable area 272 is limited to a part of the light-receiving area 271 and eccentric from the optical axis of the lens 232, the detection direction D of the optical distance sensor 201 becomes a direction inclined from vertically downward. Therefore, in the fourth embodiment, the detection direction D of the optical distance sensor 201 can be changed by changing the usable area 272 through software processing without changing the orientation of the optical distance sensor 201.

[0158] 5. Fifth Embodiment The differences between the fifth embodiment and the first embodiment will be explained below. For aspects not explained, the same configuration as that used in the first embodiment will be used in the fifth embodiment.

[0159] Figure 28 is a schematic cross-sectional view illustrating an optical distance sensor and a water tank provided in an ice maker according to the fifth embodiment.

[0160] In the fifth embodiment, as shown in Figure 28, the optical distance sensor 201 detects multiple distances to multiple locations 431 on the object 101. The determination unit 202 estimates the volume or three-dimensional shape of the ice 111 floating on the water 112 from the multiple detected distances. Multiple optical distance sensors 201 may each detect multiple distances to multiple locations 431 on the object 101.

[0161] Figure 29 is a distance value map showing multiple distance values ​​output by an optical distance sensor installed in the ice maker of the fifth embodiment. Figure 30 is a distance value map showing multiple distance values ​​output by an optical distance sensor installed in the ice maker of the fifth embodiment. Figure 31 is a graph showing the distribution of multiple distance values ​​output by an optical distance sensor installed in the ice maker of the fifth embodiment.

[0162] Figure 29 is a distance value map when ice 111 is floating in the center of a region containing multiple locations 431, and the multiple locations 431 are arranged in an 8x8 matrix of 64 locations. Figure 30 is a distance value map when ice 111 is floating in the center of a region containing multiple locations 431, and the multiple locations 431 are arranged in a 15x15 matrix of 225 locations. Figure 31 is a graph when ice 111 is floating in the center of a region containing multiple locations 431, and the multiple locations 431 are arranged in a 15x15 matrix of 225 locations. The distance values ​​to be mapped are the distance values ​​output by the optical distance sensor 201, and are the same distance values ​​as those read in step S104 of the flowchart in Figure 12, step S204 of the flowchart in Figure 13, and step S305 of the flowchart in Figure 23. The multiple locations 431 may be locations other than the 64 locations arranged in an 8x8 matrix and the 225 locations arranged in a 15x15 matrix. For example, the multiple locations 431 may be 144 locations arranged in a 12x12 matrix, 16 locations arranged in a 4x4 matrix, and so on.

[0163] As shown in Figures 29 to 31, the output distance values ​​are larger in the center of the region where the ice 111 is floating, and decrease as you move from the center of the region where the ice 111 is floating towards the periphery of the region where the ice 111 is not floating.

[0164] Next, the procedure for determining the volume of ice 111 from multiple distance values ​​is explained. The procedure described below is for the case where water 112 is transparent.

[0165] The volume V of ice 111 floating in water 112, the volume V1 of the portion of ice 111 above the water surface in water 112, and the volume V2 of the portion of ice 111 below the water surface in water 112 satisfy equation (1).

[0166] V = V1 + V2 (1)

[0167] The volume V1 of the portion of ice 111 above the water surface is obtained by integrating the product of the area Sx occupied by section x and the distance Dx to section x over all sections, as shown in equation (2).

[0168] V2 = ∫(Sx·Dx)dx (2)

[0169] In equation (2), the area Sx increases as the vertical distance from the optical distance sensor 201 to the storage 131 increases. The distance value Dx in equation (2) is estimated from the distance value output by the optical distance sensor 201, and if the ice 111 is opaque ice, it is the distance value output by the optical distance sensor 201 itself.

[0170] The density ρi of ice 111, the density ρw of water 112, and the acceleration due to gravity g satisfy equations (3) and (4), assuming that the density of ice 111 is uniform, because the gravitational force acting on ice 111 balances the buoyant force generated by the subsurface portion of ice 111 displacing water 112.

[0171] ρi·V·g=ρw·V2·g (3) V = (ρw / ρi) × V² (4)

[0172] From equations (1) and (4), the volume V of ice 111 is given by equation (5).

[0173] V = {ρw / (ρw-ρi)} × V1 (5)

[0174] The density ρi of ice 111 at 0°C is 0.9168 g / cm³. 3 The fact that the density ρw of water at 0°C is 0.9998 g / cm³ is also a factor. 3 Therefore, the coefficient (ρw / ρw-ρi) is approximately 12. For this reason, the volume V of ice 111 is expressed by equation (6).

[0175] V ≈ 12·V1 (6)

[0176] In reality, the density of ice 111 is often not uniform due to the inclusion of air bubbles in the ice 111, etc. For this reason, equation (5) may be corrected to be expressed as equation (7) using a density correction coefficient k related to the transparency of ice 111 and a parameter A indicating the transparency of ice 111.

[0177] V = (ρw / ρw - ρi·k·A) × V1 (7)

[0178] When calculating the volume V of the ice 111, preferably, multiple distance values ​​are output at a calm surface where the water 112 surface is not rippling, and thresholds are applied to these multiple distance values. This makes it possible to suppress the influence of fluctuations in the water surface of the water 112 caused by mechanical vibrations occurring inside the ice maker on the calculation of the volume V of the ice 111.

[0179] Next, an example calculation following the above procedure will be explained.

[0180] The density ρi of ice 111 at 0°C is 0.9168 g / cm³. 3 The density ρw of water at 0°C is 0.9998 g / cm³. 3 The fact that the density of air at 0°C is ρair is 0.0012 g / cm³ 3 Considering this, the volume V of ice 111 can be calculated from equation (5) as follows:

[0181] V={0.9998 / (0.9998-0.9168)}×74.8047 = 901.1cm 3

[0182] Furthermore, the volume V of ice 111 can be calculated from equation (7) as follows:

[0183] V={0.9998 / (0.9998-0.9168×0.8)}×74.8047 = 280.91cm 3

[0184] The coefficient "0.8" in the above equation is the value of the coefficient "k·A" in equation (7).

[0185] The volume of ice 111 calculated from equation (5) is 901.1 cm³. 3 As can be seen from the fact that the volume of ice 111 calculated from equation (7), 280.91 cm³, is smaller, when equation (5) is corrected as expressed in equation (7), the calculated volume V becomes smaller when air bubbles are mixed in with the ice 111.

[0186] By calculating the total volume V of the ice 111 in this way, the ice-making state of the storage 131 can be determined. This makes it possible to make ice 111 of any size. Furthermore, even if the determination device 123 is incorporated into electronic equipment other than the ice maker 3, the melting rate of the ice 111 can be monitored.

[0187] The three-dimensional shape of ice 111 is estimated from a distance map created by mapping multiple distance values.

[0188] This disclosure is not limited to the embodiments described above, and may be replaced with configurations that are substantially the same as those shown in the embodiments, configurations that produce the same effects, or configurations that can achieve the same purpose. [Explanation of symbols]

[0189] 1,3 Ice makers 101 Target 111 Ice 112 Water 121 Water storage tank 122 Cooler 123 Judgment device 124 Controllers 131 Storage 141 Inclusions 151 Cooling rod 161 Horizontal position 171 modules 181 The First Light 182 The Second Light 183 The Third Light 191 Detection results 192 Results of the judgment 201 Optical distance sensor 202 Judgment section 203 First Memory Unit 204 Output Unit 211 Light-emitting element 212 Photodetector 213 Control elements 214 MCU (MCU) 215 Second Memory Unit 216 Photodetector 221 Signal 222 Control Instructions 223 Light emission control 224 Light Reception Control 225 settings 231 Packages 231a Interior space 231b First opening window 231c Second opening window 232 lenses 233,234 Optical Filters 235 Light-shielding resin 236 Integrated Circuits (ICs) 241 Si substrate 251 circuits 261 SPAD 271 Light receiving area 272 Usage area 281 First experimental apparatus 291,292 horizontal position 301 Second experimental apparatus 311,312 Horizontal range 321 Third experimental apparatus 331 Container 341 Range 351 The fourth experimental apparatus 361 Specular reflection component 362 Scattered reflection component 371 Opaque Ice Range 381,382 401 Changes 411 Posture Change Unit 421 Area of ​​Use Change Section 431 Multiple locations

Claims

1. An optical distance sensor that detects the distance to the target, A processing unit that determines whether the object is ice or water based on the distance, A determination device equipped with the following features.

2. The processing unit obtains the water level of the target from the distance. The determination device according to claim 1.

3. Performing the determination based on the distance includes determining that the object is ice if the difference obtained by subtracting the reference distance from the distance is greater than a threshold, and determining that the object is water if the difference between the reference distance and the distance is less than a set difference. The determination device according to claim 1.

4. The processing unit uses the distance detected by the optical distance sensor as the reference distance when the target is water. The determination device according to claim 3.

5. The optical distance sensor emits a first light, receives a second light generated by the object reflecting the first light, detects the distance based on the time from the emission of the first light to the receipt of the second light, and detects the amount of light of the second light. The processing unit performs the determination based on the distance and the amount of light. The determination device according to claim 1.

6. Performing the determination based on the distance and the light intensity includes determining that the object is ice if the difference obtained by subtracting the reference distance from the distance is greater than a threshold and the decrease in the light intensity from the reference light intensity is greater than a set decrease, and determining that the object is water if the difference between the reference distance and the distance is less than a set difference. The determination device according to claim 5.

7. The processing unit, when the target is water, uses the distance and light intensity detected by the optical distance sensor as the reference distance and reference light intensity, respectively. The determination device according to claim 6.

8. Performing the determination based on the distance and the light intensity includes determining whether the object is opaque ice or water based on the amount of light at inclination detected by the optical distance sensor when the detection direction of the optical distance sensor is inclined from vertically downward. The determination device according to claim 5.

9. Determining whether the object is opaque ice or water based on the amount of light at the time of inclination includes determining that the object is opaque ice if the amount of light at the time of inclination is greater than the set amount of light, and determining that the object is water if the amount of light at the time of inclination is less than the set amount of light. The determination device according to claim 8.

10. Determining whether the object is opaque ice or water based on the amount of light at the time of tilt includes obtaining a parameter indicating the transparency of the object from the amount of light at the time of tilt, and determining whether the object is opaque ice or water based on the parameter. The determination device according to claim 8.

11. Performing the determination based on the distance and light intensity includes determining whether the object is transparent ice based on the vertical distance and vertical light intensity detected by the optical distance sensor when the detection direction is vertically downward. The determination device according to claim 8.

12. The device includes a modification unit that changes the detection direction to a direction inclined from the vertical downward direction or to the vertical downward direction. The determination device according to claim 11.

13. The modification unit includes a posture changing unit that changes the posture of the optical distance sensor. The determination device according to claim 12.

14. The optical distance sensor has a working area used to receive the second light, The modification unit includes a usage area modification unit that modifies the usage area. The determination device according to claim 12.

15. The optical distance sensor detects multiple distances to multiple locations on the target, The processing unit estimates the volume or three-dimensional shape of the ice floating on the water from the plurality of distances. The determination device according to claim 1.

16. A cooler for cooling the stored material, A determination device according to any one of claims 1 to 15, A controller that controls the cooler based on the result of the determination, An ice maker equipped with [a specific feature].

17. An electronic device comprising a determination device according to any one of claims 1 to 15.

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