JP2010152860A - Operation input device - Google Patents

Abstract

An object of the present invention is to provide a highly reliable operation input device that selectively detects only a human finger, efficiently guides reflected light to the light receiving element, increases the amount of received light, and enables reliable operation input. .
A plurality of different wavelengths are irradiated, reflected light from a reflective object such as a finger is received, and a key switch operation is performed from each received light amount and a first threshold value output from a first threshold value holding means. Since it is possible to discriminate the presence or absence of each of the received light amount and the second threshold value output by the second threshold value holding means, the finger of the adult and the infant can be discriminated and the operation of the device by the infant can be prohibited. The operation input device is capable of inputting and having high reliability.
[Selection] Figure 1

Description

  The present invention relates to an optical operation input device for household electrical appliances.

  Conventionally, household electrical appliances such as water heaters, washing machines, and cooking heaters are equipped with a panel-type operation input device having a drip-proof function, in which operation switches for operating these devices are concentrated. (For example, refer to Patent Document 1).

  FIG. 8 is a side sectional view of the switch operating device of the conventional cooking device described in Patent Document 1. In FIG. 8, an operation panel 5 in which a waterproof film 9 is integrally molded in advance is bonded to an operation panel mounting portion 6 provided on the outer shell 1 of the cooker body, and a push switch 2 on an internal control circuit board 4 is bonded. Can be secured from the operation button unit 10 via the switch operation button 14 to ensure water tightness to the inner surface, and the surface has a smooth texture and can withstand heat during cooking. Yes. If the waterproof film 9 is made of a flexible electrical insulating material, for example, a polyethylene terephthalate resin film, the center part is normally elastic, and when pressed, it is reversed downward to release the pressure. Therefore, it has a clearer snap function than that by only the spring force of the push switch 2.

  There are also known capacitive and optical operation input devices that do not require a mechanical operating part, have a light operational feeling, and have higher confidentiality (see, for example, Patent Document 2 and Patent Document 3). ).

  As medical devices, a pulse wave detection device that derives an electrical signal corresponding to a pulse wave using light or infrared rays of a plurality of wavelengths, and a blood saturation oxygen concentration detection device are known. When visible light and infrared light are emitted and received separately by the light receiving unit, the oxidation state of hemoglobin can be determined based on the difference in received light intensity depending on the wavelength. Since the oxidation state of hemoglobin corresponds to the saturated oxygen concentration in the blood, if a calibration curve or the like is prepared in advance corresponding to the standard oxygen concentration, it can be calculated as the saturated oxygen concentration ( For example, see Patent Document 4).

  FIG. 9 is a main body perspective view (a) of a conventional heating cooker described in Patent Document 2 and a cross-sectional view (b) of an operation unit. In FIG. 9, induction heating type cooking units 24 and 25 are arranged on the plate 22 on the left and right sides of the front side where the user cooks, and a heater heating type cooking unit 26 is arranged on the central back side. Operation / display units 27, 28, and 29 corresponding to the cooking units 24, 25, and 26 are provided on the front side of the cooking units 24, 25, and 26, and the contact units 27a, 28a, and 29a are provided on the plate 22. When the user contacts from the front side, the electrostatic capacity type switch 43 arranged below the plate 22 is configured to be operable. The operation switch 43 includes a planar electrode 43a (not shown) formed of copper on the operation circuit board 42, and a shield electrode 43b (not shown) surrounding the planar electrode 43a. It is provided to determine the contact range and is grounded). The switch function can be arranged directly on the surface of the tempered glass plate corresponding to the position where the operation means exists, and it can be made flat without projections such as operation elements and operation buttons. Is easier.

JP-A-6-209849 Japanese Patent Laid-Open No. 10-214677 JP 2000-100287 A JP 2001-46345 A

  However, in the conventional configuration, the operation panel integrally formed with a waterproof film and the resistive touch panel have a high temperature during cooking (up to 350 ° C when fried) due to the limitation of the heat resistant temperature of the film material. The pan cannot be placed directly. Further, the capacitance type switch has a problem that it accepts an operation input even when seasoning liquid or water is spilled on the plate.

  Further, in the case of an optical switch, there is a problem that a reflective object other than a human finger, for example, a cloth cloth or paper, is mistakenly placed on the key switch operation surface, and is accepted as an operation input. Had.

  Further, in the configuration in which the conventional health condition monitoring device is directly applied to a heating cooker, the light reflected from the finger is attenuated while passing through the protective film or plate that is the contact portion of the operation input device. The detection ability of the camera is reduced, and there is a problem that reliable operation cannot be performed.

  The present invention solves the above-mentioned conventional problems, and selectively detects only a human finger, efficiently leads the reflected light to the light receiving element, increases the amount of received light, and enables reliable operation input. An object of the present invention is to provide a highly reliable operation input device.

  In order to solve the conventional problems, a translucent plate having a key switch operation surface of a device, a light emitting element that emits light having different peak wavelengths disposed on the back side of the operation surface of the plate, and the light emitting element A light receiving element for detecting reflected light reflected by a reflecting object such as a finger touching the front side of the operation surface on the plate, a wavelength selecting means for switching the wavelength of the light emitting element, and the wavelength selecting means Storage means for storing the received light amount from the selected light emitting element for each wavelength and for each key switch, first threshold value holding means for holding a first threshold value for determining the presence or absence of reflected light, and a finger A key switch based on a second threshold value holding means for holding a second threshold value for discriminating the magnitude of each of the received light amount, a received light amount stored in the storage means, and a first threshold value output from the first threshold value holding means Control And determining means for determining the finger of the adult and the infant from each received light amount and the second threshold value output from the second threshold value holding means, and the operation of the device by the operation of the infant is provided. By prohibiting, reliable operation input is possible and the operation input device is highly safe.

  Further, the wavelength switched by the wavelength selection means is between 0.5 μm and 3.5 μm, which is the light transmission characteristic of the translucent plate having the key switch operation surface of the device, and the spectral characteristic of the human finger. By setting based on this, it becomes possible to selectively detect only a human finger, and a highly reliable operation input device can be obtained.

  Also, an illuminance sensor is provided on the lower surface of the plate, and the first threshold value held by the first threshold value holding means and the second threshold value held by the second threshold value holding means under sunlight or strong illumination, By correcting to a predetermined value larger than usual, a more reliable operation input device is obtained.

The operation input device of the present invention irradiates a plurality of different wavelengths, receives reflected light from a reflecting object such as a finger, and receives each received light amount and the first threshold value output from the first threshold value holding means. Because it is possible to discriminate whether or not a key switch is operated, and to discriminate the fingers of adults and infants from the respective received light amounts and the second threshold value output from the second threshold value holding means, thereby inhibiting the operation of the device by the infants. Therefore, reliable operation input is possible and the operation input device is highly reliable.

(A) Operation panel plan view of the operation input device according to the first embodiment of the present invention (b) Main part sectional view of the operation input device according to the first embodiment of the present invention The block diagram of the operation input device in Embodiment 1 of this invention (A) Main part sectional view of the operation input device in Embodiment 2 of the present invention (b) Main part sectional view of the second light guide of the operation input device in Embodiment 2 of the present invention The block diagram of the operation input device in Embodiment 2 of this invention Graph showing the correlation between absorbance and wavelength of reflective objects (A) Main part sectional drawing of the jar rice cooker which mounts the operation input apparatus in Embodiment 3 of this invention (b) The top view of the jar rice cooker which mounts the operation input apparatus in Embodiment 3 of this invention The block diagram of the operation input device in Embodiment 4 of this invention Cross section of the main part of a conventional waterproof film integrated operation input device (A) Perspective view of a conventional cooking device (b) Cross-sectional view of main parts of a conventional cooking device The block diagram of the operation input device in Embodiment 5 of this invention The block diagram of the operation input device in Embodiment 6 of this invention

  According to a first aspect of the present invention, there is provided a translucent plate having a key switch operation surface of an apparatus, a light emitting element that emits light having different peak wavelengths disposed on the back side of the operation surface of the plate, and light from the light emitting element. A light receiving element that detects reflected light reflected by a reflecting object such as a finger touched on the front side of the operation surface on the plate, a wavelength selecting unit that switches a wavelength of the light emitting element, and the wavelength selected by the wavelength selecting unit Storage means for storing the amount of light received from the light emitting element for each wavelength and each key switch, first threshold value holding means for holding a first threshold value for determining the presence or absence of reflected light, and the size of a finger Whether or not a key switch is operated based on a second threshold value holding means for holding a second threshold value, a received light amount stored in the storage means, and a first threshold value output from the first threshold value holding means. Discriminate, And a discriminating means for discriminating the finger of the adult and the infant from each received light amount and the second threshold value output from the second threshold value holding means, and prohibiting the operation of the device by the infant's operation, Operation input becomes possible, and the operation input device is highly safe.

  In the second to fourth inventions, the wavelength to be switched by the wavelength selecting means is between 0.5 μm and 3.5 μm, which is the light transmission characteristic of the translucent plate having the key switch operation surface of the device, and short. By setting the wavelength on the wavelength side to 0.65 μm or less where hemoglobin in blood exhibits absorption characteristics, and the wavelength on the long wavelength side to less than 1.5 μm and 0.65 μm or more, which does not exhibit water absorption characteristics, By setting based on the spectral characteristics of the finger, it is possible to selectively detect only a human finger, and a highly reliable operation input device can be obtained.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the invention, the key switch operation surface is provided with an elliptical groove in the shape of a finger, and the light emitting element and the light receiving element are disposed in the groove to operate Performance can be improved, and the influence of ambient light can be reduced, enabling reliable operation input.

  In a sixth aspect of the invention, an illuminance sensor is provided on the lower surface of the plate, and the first threshold value held by the first threshold value holding means and the second threshold value held by the second threshold value holding means under sunlight or strong illumination. By correcting the threshold value to a predetermined value larger than usual, it is possible to obtain a more reliable operation input device.

  According to the seventh aspect of the present invention, a more reliable operation input device is obtained by increasing the light emission amount of the light emitting element by a predetermined amount in accordance with the output of the illuminance sensor.

  According to the eighth aspect of the present invention, a more reliable operation input device is obtained by subtracting a predetermined amount from the amount of light received by the light receiving element in accordance with the output of the illuminance sensor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
Fig.1 (a) is a top view of an induction heating cooking appliance as an example of the household appliances which mount the operation input apparatus in the 1st Embodiment of this invention, FIG.1 (b) is the principal part of the same operation input apparatus. A sectional view and FIG. 2 are block diagrams of the operation input device.

  1 and 2, a key switch operation surface 51 and a heating power amount display 52 are provided on a plate 50 made of translucent heat-resistant tempered glass or the like on which an object to be heated is placed. On the key switch operation surface 51, patterns (icons) indicating control contents of the cooking device are printed as key switches 51a to 51c, and the user touches one of the icons in the key switches 51a to 51c with the finger 53. The cooker is operated by this. On the operation circuit board 54, the key switches 51 a to 51 c are reflected by the light emitting elements 55 a to 55 c that irradiate light having a plurality of different wavelengths with a single element, the wavelength selection unit 56, and the finger 53. In addition, a single light receiving element 57 that receives the reflected light of the plurality of wavelengths, an IV conversion means 58 that converts a photocurrent detected by the light receiving element 57 into a voltage, and an output of the IV conversion means 58 Storage means 59 for storing voltages (E1a, E2a, E1b, E2b, E1c, E2c) proportional to the received light amount for each key switch and each wavelength, and the reflection of the plurality of wavelengths from the output of the storage means 59 The presence or absence of operation of the key switches 51a to 51c is calculated from the received light amount ratio (E1a / E2a, E1b / E2b, E1c / E2c) and the first threshold value E3 held by the first threshold value holding means 61. Discrimination The determination means 60 for determining the finger of the adult and the infant by calculating from the second threshold value E4 held by the second threshold value holding means 62 and the received light amount ratio of the reflected light of the plurality of wavelengths is mounted. is there.

  Further, a V-shaped light guide 61 is provided between the light emitting elements 55 a to 55 c and the plate 50 and between the plate 50 and the single light receiving element 57. In order to efficiently propagate the plate 50, the irradiation light, and the reflected light from the finger 5, it is filled with an optical adhesive 62 so as not to sandwich an air layer between the light guide 61 and the light emitting elements 55a to 55c. The light receiving element 57 is fixed so as to face the operation circuit board 54 at a predetermined angle.

  The light guide 63 is made of a material having a value close to the refractive index (≈1.541) of the plate 50. For example, polycarbonate whose refractive index is controlled (under a low refractive index), a resin whose epoxy resin contains sulfur or fluorine, and whose content is controlled (controllable with an accuracy of ± 0.001), or non- A polyolefin resin, which is a crystalline transparent plastic, and a composite resin of a plurality of elements are used. Thereby, almost all of the light emitted from the light emitting elements 55 a to 55 c is irradiated to the finger 53 without being reflected by the lower surface of the plate 50. Further, on the light receiving element side of the light guide 63, an elliptical paraboloid calculated so that the optical path to the light receiving element 57 of the reflected light is substantially equal regardless of the position of the finger 53 on the key switches 51a to 51c. (X2 / a2 + y2 / b2 = 2z) or hyperbolic paraboloid (x2 / a2-y2 / b2 = 2z) is used. Since the refractive index of the light guide 61 is adjusted to the refractive index of the plate 50, most of the reflected light reflected by the finger 53 is guided to the light receiving element 57 while totally reflecting or traveling straight inside the light guide 58. As a result, the S / N ratio can be kept high.

  About the induction heating cooking appliance comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  The user puts the food in a pan capable of induction heating and places it in a heating area 65 on the plate 50 indicated by a ring pattern. When the power outlet is inserted into the commercial power supply, a key input permission signal and a driving voltage are supplied from a main control circuit 66 (not shown), and the light emitting elements 55a to 55c selected by the wavelength selection unit 56 are sequentially light having different peak wavelengths. The key is ready for operation. When no object is present on the key switches 51a to 51c, the irradiation light enters from the end face of the light guide 63 and propagates through the light guide 63 while repeating straight or total reflection. Permeated and released to the sky. At this time, since the reflected light is not received by the light receiving element 57, the amount of reflected light E1a≈E2a≈E1b≈E2b≈E1c≈E2c≈ As a result of calculating the light quantity ratio corresponding to each key switch, the discrimination means 60 discriminates that there is no key operation and does not output a key input signal, so no heating operation or the like is performed. .

  Next, when a reflecting object such as the finger 53 is present on the key switch 51b, the irradiation light is diffusely reflected by the finger 53 or the like, and travels straight or totally inside the light receiving side paraboloid of the light guide 63. Then, the light is received by the light receiving element 57, a photocurrent flows due to the photoelectric effect, and the voltages E1b and E2b proportional to the amount of reflected light are output from the IV conversion means 58 and stored in the storage means 59. The discriminating means 60 compares the stored reflected light quantity ratio E1b / E2b with the first threshold value E3, discriminates that the key switch 51b has been operated, and outputs a key input signal b. The main control circuit 66 inputs this key input signal b and starts a heating operation by electromagnetic induction. Similarly, when the finger 53 has a reflective object on the key switch 51a, the heating power is reduced, and when the finger 53 has a reflective object on the key switch 51c, the heating power is increased. Then, when cooking is finished and the user touches the key switch 51b with the finger 53 again, the heating operation is stopped.

  On the other hand, when the infant tries to operate the device by mistake, the voltages E1b ′, E2b ′, E3b ′ received by the light receiving element 57, converted by the IV conversion means 58, and stored in the storage means 59 are Since the size of the finger 53 is smaller than that of an adult and smaller than the second threshold value E4, the discrimination means 60 outputs a key lock signal, the main control circuit 66 treats that there is no key switch operation, and the adult Do not turn on / off the heating and change the heating amount.

  As described above, in the present embodiment, since the refractive index of the light guide 61 provided between the light emitting element and the plate 50 that is the operation surface is equal to that of the plate 50, the reflection reflected by the reflecting object such as the finger 52 is reflected. Since the light is guided to the light receiving element 57 by the light receiving side paraboloid shape of the light guide 61, the amount of received light is stabilized, and reliable operation input is possible even through the plate 50. In addition, two types of light having different wavelengths are emitted from the light emitting elements 55a to 55c, and the ratio of the amount of reflected light received is calculated. Therefore, there is less influence on disturbance light, changes with time of the light emitting elements, and the like. The operation input device can be highly reliable, and further includes a discrimination means for discriminating the finger of an adult and a child from being held by the second threshold value holding means, and the operation of the device by the operation of the child can be prohibited. Therefore, it becomes possible to improve safety.

  In addition, the optical operation input means of this embodiment is optical, so no operating force is required (you can operate the switch without touching it by simply bringing your finger close to it), and it can be differentiated in terms of design and operation. Lifetime is semi-permanent, dust-proof and waterproof structure is possible, and the ratio of the amount of reflected light received by multiple wavelengths is calculated. .

  The light-emitting element may be a two-color (RG, RB, BG) light-emitting LED or a three-color (full color) LED, and may sequentially emit light at a plurality of different wavelengths.

  In addition, since a high-speed key switch response such as a game machine is not required, rather a reliable operation input is required, the number of key switches × multiple wavelengths × pulse width = total input time, compared to conventional input devices However, no problem occurs even if the input time is long.

  Further, the wavelength selection means, the storage means, and the discrimination means may be realized by an inexpensive microcomputer with a small number of pins in which ROM, RAM, I / O, and A / D are integrated on one chip.

(Embodiment 2)
FIG. 3 is a cross-sectional view of an essential part of the operation input device according to the second embodiment of the present invention, FIG. 4 is a block diagram of the operation input device, and FIG. 5 is a diagram showing oxygenated hemoglobin contained in the human finger and moisture. It is the graph which showed the absorption characteristic. In addition, about the same part as the operation input device of the heating cooker in the said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  3 and 4, on the operation circuit board 54, the light emitting elements 65a to 65c that emit light of the first wavelength and the light emitting elements that emit light of the second wavelength are provided for each of the key switches 51a to 51c. 66a to 66c, wavelength selection means 67, a single light receiving element 68 that receives the reflected light of the plurality of wavelengths reflected by the finger 53, and an I that converts the photocurrent detected by the light receiving element 68 into a voltage. -V conversion means 58 and storage means 59 for storing voltage (E1a, E2a, E1b, E2b, E1c, E2c) proportional to the amount of light received for each key switch and each wavelength output from this IV conversion means 58 From the output of the storage means 59, the received light amount ratio (E1a / E2a, E1b / E2b, E1c / E2c) of the reflected light of the plurality of wavelengths is calculated and the first threshold value holding means 61 outputs the first Threshold E3 and In comparison, it is determined whether or not the key switch is operated, and the second threshold value E4 output from the second threshold value holding means 62 is compared with the ratio of the amount of reflected light received. A determination means 60 for determining is mounted.

  Further, a light-transmitting first light guide 69 a is provided between the first light-emitting elements 65 a to 65 c and the second light-emitting elements 66 a to 66 c and the plate 50, and a light-transmitting action is provided between the plate 50 and the light-receiving element 68. A second light guide 69b is provided. The first light guide 69a and the second light guide 69b are formed by integral molding, and the total reflection is caused by the difference in refractive index between the constituent material (refractive index = 1.541) and air (refractive index = 1). Is used to efficiently guide light to the operation surface and the light receiving element 25. For example, in a speedometer of an automobile, it is used as a needle or a scale portion, and in a liquid crystal display as a backlight portion. In the present embodiment, the refractive index of the portion 70 in contact with the plate 50 of the first light guide 69a (light emitting element side) is determined by applying an optical adhesive or paint, pasting a resin sheet, or having a high refractive index. The material is made smaller by, for example, embedding it in a linear shape so that reflected light from the lower surface of the plate 50 is not generated. That is, the design is such that the relationship between the respective transmittances is such that the transmittance of the plate 50 <the transmittance of the portion 70 in contact with the plate 50 <the transmittance of the first light guide 69a. Thereby, the light irradiated from the light emitting elements 65a to 65c and the second light emitting elements 66a to 66c is guided from the first light guide 69a to the plate 50 with almost no reflected light. On the other hand, the light reflected by the reflecting object 53 such as a finger does not return to the first light guide 69a side because the total reflection condition is satisfied, and most of the light is received by the second light guide 69b by the light receiving element 68. Therefore, the S / N ratio (ratio of reflected light and disturbance light, ratio with and without key operation) can be kept high.

Next, when a reflecting object such as the finger 53 exists on the key switches 51a to 51c, the irradiation light is diffusely reflected by the finger 53 and the like, and the inside of the light receiving side paraboloid shape of the second light guide 69b. Then, the light is received by the light receiving element 57 and photocurrent flows due to the photoelectric effect, and the voltages E1a to E1c proportional to the amount of reflected light from the IV conversion means 58 (depending on the first light emitting element). Reflection light amount), E2a to E2c (reflection light amount by the second light emitting element) are output and stored in the storage means 59. The discriminating means 60 uses the stored reflected light amount ratio E1a / E.
2a, E1b / E2b, E1c / E2c are compared with the first threshold value E3 to determine that the key switches 51a to 51c have been operated, and key input signals a to c are output.

  On the other hand, when the infant tries to operate the device by mistake, the voltages E1b ′, E2b ′, E3b ′ received by the light receiving element 57, converted by the IV conversion means 58, and stored in the storage means 59 are Since the size of the finger 53 is smaller than that of the adult and smaller than the second threshold value E4, the discriminating means 60 outputs a key lock signal, the main control circuit 66 treats that the key switch is not operated, and the adult operates Do not turn on / off the heating and change the heating amount.

  Further, as shown in the graph of FIG. 5, oxyhemoglobin is strongly absorbed in the visible light region of 650 nm or less, and moisture is strongly absorbed in the region exceeding 1100 nm. About 70% of human tissue is occupied by water, and considering that light in the visible to infrared range is absorbed mainly by water and oxyhemoglobin in the living body, a wavelength range of more than 650 nm and less than 1200 nm. Light (near infrared light) is suitable for non-detection of the human body. On the other hand, tempered glass used for the top plate (top plate) of induction heating cookers is a crystallized glass in which fine crystals are precipitated by reheating glass with a special composition in order to increase strength while having heat resistance. 80% or more of light having a wavelength of 0.5 μm to 2.6 μm is transmitted, and approximately 30% of light having a wavelength of 3 to 4 μm is transmitted, and has a wavelength longer than 4 μm and 0.5 μm. Since light having a shorter wavelength is hardly transmitted, an LED having a wavelength of 563 nm (pure green) or 591 nm (yellow) is used as the first light emitting element, and a laser diode having a wavelength of about 1100 nm is used as the second light emitting element. be able to. As the light receiving element, PIN-PD or the like can be used.

Further, the reflection characteristics of the object for detecting presence / absence of key operation are arranged as follows.
1. Human finger (oxygenated hemoglobin, water)
1. Both an absorption spectrum of oxyhemoglobin (650 nm or less) and a moisture absorption spectrum (1200 nm or more) are shown. 2. An absorption spectrum (1200 nm or more) of spilled water or cooking liquid water on the key switch operation surface of the plate 50. Pan (metal, earthenware) placed on the 50-key switch operation surface of the plate
Therefore, it can be determined that the finger 53 has reflected light when the first light emitting element is irradiated and the reflected light is present when the second light emitting element is irradiated.

  As described above, in this embodiment, an element having a wavelength of 650 nm or less is used as the first light-emitting element that emits light on the short wavelength side (λ1 in FIG. 5) out of light having a wavelength of 0.5 μm to 3.5 μm. The second light emitting element that emits light on the long wavelength side (λ2 in FIG. 5) is an element having a wavelength of less than 1500 nm (and 650 nm or more), and is sequentially turned on. By calculating, it is possible to obtain a highly reliable operation input device that is sensitive only to a human finger.

  Since the operation method is a fingertip, the temperature range of the operation surface sufficiently cooled by the intake air generated by the blower fan built in the cooking device is kept at 0 to 40 ° C., and the plate 50 itself of this operation surface portion is The radiated infrared energy is concentrated to a wavelength of 3.5 μm to 65 μm according to Stefan-Boltzmann law. Moreover, the temperature of the cooking container at the time of cooking is about 30 ° C. to 350 ° C., and the peak wavelength of infrared rays radiated by an object at this temperature is 5 μm to 10 μm according to Planck's radiation law, and the total energy radiation is Stefan Boltzmann's According to the law, it is collected to 1.8 μm to 65 μm. Among these, infrared light of 1.8 μm to 4 μm is transmitted through the plate 50 and enters the outer shell of the cooker body, but a light shielding material (not shown) is provided so as not to enter the light receiving element 58 directly. .

The induction heating is connected in parallel to the first smoothing capacitor from the commercial power source through the diode bridge, and this DC voltage is converted into a high-frequency current by an inverter circuit, and then a predetermined gap is formed facing the object to be heated 32. The high-frequency magnetic field is generated by supplying to the heating coil that is arranged, and the cooking vessel is induction-heated. For this reason, since there is a lot of electromagnetic induction noise such as high-frequency current supplied to the heating coil and switching noise of the DC power supply, noise removal processing (delay) time is provided for detection of photocurrent to prevent malfunction. Generally, a cooking device does not require a high-speed key switch response like a game machine, but rather requires a reliable operation input, so the number of key switches x multiple wavelengths x pulse width = total input There is no problem even if the time and the input time are longer than those of the conventional input device.

(Embodiment 3)
FIG. 6 (a) is a cross-sectional view of the main part of a jar rice cooker equipped with an operation input device according to the third embodiment of the present invention, and FIG. 6 (b) is a plan view of the rice cooker (omitted, hereinafter, The same as the description method of Embodiment Mode 1).

  In FIG. 6, 80 is a body, 81 is a pot for containing rice and water, 82 is a temperature sensor for detecting the temperature of the pot, 84 is an operation board, 85 is an optical operation switch in the third embodiment, 86 Is a heating control circuit board for induction heating, and 87 is a waterproof film type push switch.

  The operation surface of the optical operation switches 85a and 85b is provided with an elliptical groove in the shape of a finger, and a light emitting element and a light receiving element are arranged in the groove, thereby improving the operational feeling and due to ambient light. The effect is reduced and reliable operation input is possible.

  Since the main operations in the jar rice cooker are “cooking start / stop” and “heat retention / off”, these two are assigned to the optical operation switch, and the remaining time setting keys and course selection keys are By controlling the cost as a conventional waterproof film type push switch, the operation input device of the present invention can be mounted even on a low-priced product such as a jar rice cooker.

(Embodiment 4)
FIG. 7 is a block diagram of an operation input device according to the fourth embodiment of the present invention. In addition, about the same part as the operation input device of the heating cooker in the said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In FIG. 7, an illuminance sensor 90 is provided on the lower surface of the plate 50, and its output is input to the determination means 60. When the output of the illuminance sensor 90 is greater than a predetermined value, the determination unit 60 detects that the light is under sunlight or strong illumination, and the first threshold E3 held by the first threshold holding unit 61 and the second threshold By adding a predetermined correction value to the second threshold value E4 held by the threshold value holding means 62, it is determined whether or not the key switches 51a to 51c are operated, and the fingers of the adult and the infant are determined. Thus, a more reliable operation input device can be obtained.

(Embodiment 5)
FIG. 10 is a block diagram of an operation input device according to the fifth embodiment of the present invention. In addition, about the same part as the operation input device of the heating cooker in the said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In FIG. 10, a constant current power source 91 that supplies a predetermined current to the light emitting elements 55 a to 55 c is provided separately from the driving voltage of the main control circuit 66 (not shown), and the output current value of the illuminance sensor 90 is the output current value. Variable according to output.

  As an operation and function thereof, when the output of the illuminance sensor 90 is larger than the ambient light determination value, the key switch can be used even under sunlight or strong illumination by increasing the current value supplied from the constant current power source 91. An output sufficient to determine whether or not the operations 51a to 51c are performed is output from the light receiving element 57, so that a more reliable operation input device can be obtained.

(Embodiment 6)
FIG. 11 is a block diagram of an operation input device according to the sixth embodiment of the present invention. In addition, about the same part as the operation input device of the heating cooker in the said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In FIG. 11, a subtracting unit 92 is provided, and a value obtained by subtracting a predetermined amount from the output of the IV converting unit 58 (equal to the amount of light received by the light receiving element 57) according to the output of the illuminance sensor to the storage unit 59. Output.

  As its operation and effect, when the output of the illuminance sensor 90 is less than or equal to the ambient light determination value, zero is reduced. On the other hand, when the output of the illuminance sensor 90 is greater than the ambient light determination value, a predetermined coefficient is added to the output. The value multiplied by is subtracted from the output of the IV conversion means 58. By doing so, it becomes possible to determine whether or not the key switches 51a to 51c are operated even under sunlight or under strong illumination, and a more reliable operation input device can be obtained.

  The same effect can be obtained even if the output of the IV conversion means 58 when light is not irradiated from the light emitting elements 55a to 55c is stored in the second storage means and the value is reduced. Is clear.

  As described above, since the operation input device according to the present invention can operate the device through a translucent member such as a plate, a dustproof / waterproof structure can be easily realized. In addition, since it is optical and has no mechanical moving parts, it does not require an operating force such as a pressing operation, and its operating life can be made semi-permanent, so that it can be used not only for household appliances but also for various industrial equipment. Can also be installed.

DESCRIPTION OF SYMBOLS 50 Top plate 51 Key switch 55a-55c Light emitting element 57 Light receiving element 58 IV conversion means 59 Memory | storage means 60 Discriminating means 61 1st threshold value holding means 62 2nd threshold value holding means 63 Light guide 64 Optical adhesive 65a- 65c 1st light emitting element 66a-66c 2nd light emitting element 68 Light receiving element 69a, 69b Light guide 80 Body 81 Pan 82 Temperature sensor 83 Cover 84 Operation circuit board 85 Optical operation switch 86 Heating control circuit board 87 Waterproof push Switch 90 Illuminance sensor

Claims (8)

A translucent plate having a key switch operation surface of the device, a light emitting element arranged on the back side of the operation surface of the plate to emit light having a different peak wavelength, and light from the light emitting element on the operation surface on the plate A light receiving element that detects reflected light reflected by a reflecting object such as a finger touched on the front side, a wavelength selecting unit that switches a wavelength of the light emitting element, and an amount of light received from the light emitting element selected by the wavelength selecting unit For each wavelength and for each key switch, a first threshold value holding means for holding a first threshold value for determining the presence or absence of reflected light, and a second value for determining the size of the finger The presence or absence of key switch operation is determined from second threshold value holding means for holding a threshold value, each received light amount stored in the storage means and the first threshold value output from the first threshold value holding means, and Receipt of Amount and a second discriminating means for discriminating adults and infants finger from the threshold to the output of the second threshold value holding means, an operation input device which is characterized in that it inhibits the operation of the apparatus according to infant operation. The operation input device according to claim 1, wherein the wavelength switched by the wavelength selection unit is 0.5 μm to 3.5 μm, which is a light transmission characteristic of a translucent plate having a key switch operation surface of the device. The operation input device according to claim 2, wherein the wavelength on the short wavelength side is set to 0.65 μm or less where hemoglobin in blood exhibits absorption characteristics. The operation input device according to claim 2 or 3, wherein the wavelength on the long wavelength side is less than 1.5 μm and 0.65 μm or more which does not show water absorption characteristics. The key switch operation surface is provided with an elliptical groove in the shape of a finger, and a light emitting element and a light receiving element are arranged in the groove to improve operability and reduce the influence of ambient light to ensure reliable operation input. The operation input device according to claim 1, wherein the operation input device is enabled. An illuminance sensor is provided on the lower surface of the plate, and the first threshold value held by the first threshold value holding means and the second threshold value held by the second threshold value holding means are more than usual under sunlight or strong illumination. The operation input device according to claim 1, wherein the operation input device is corrected to a large predetermined value. The operation input device according to claim 6, wherein the light emission amount of the light emitting element is increased by a predetermined amount according to the output of the illuminance sensor. The operation input device according to claim 6, wherein a predetermined amount is subtracted from the amount of light received by the light receiving element in accordance with an output of the illuminance sensor.