JP3297627B2 - Electric rice cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electric rice cooker having a microcomputer control unit and a liquid crystal display.

[0002]

2. Description of the Related Art In a recent electric rice cooker, a microcomputer control unit controls a heating means such as a heater and a work coil, and displays a rice cooking menu, a cooking level, a timer setting time, and the like set by operation switches, for example, on a liquid crystal display. Is displayed.

In order to reduce the cost, the power supply voltage for operating the microcomputer control unit is to drop the AC power supply voltage 100 (V) by, for example, a voltage drop means comprising a resistor, instead of a general transformer. Thus, a desired voltage is obtained.

[0004]

However, since the liquid crystal display itself is a light-receiving electronic display element without a self-light source, the contrast on the display surface is poor, and it is very difficult to see it in a dark place such as a kitchen or at night. There are drawbacks.

Therefore, some expensive products such as a word processor employ a configuration in which a backlight that is lit and driven by a dedicated power supply is provided to make it easy to see. However, such a special configuration is used in an electric rice cooker. When the power supply and the backlight are provided, there is a problem that the cost is significantly increased.

When a voltage drop means using only a resistor is employed to obtain the power supply voltage for operating the microcomputer control unit as described above, the power consumption generated in the resistance portion of the voltage drop means is generally converted into heat. It is wasted because it is only released.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. A voltage drop means for obtaining a power supply voltage for operating the microcomputer control unit is formed by a light emitting means such as a light emitting diode. Another object of the present invention is to provide a low-cost and energy-saving electric rice cooker which solves the above-mentioned problems by also using the light emitting means as a backlight light source of the liquid crystal display.

[0008]

Means for Solving the Problems In order to achieve the above object, the present invention is provided with the following means for solving the problems.

That is, the electric rice cooker according to the first aspect of the present invention comprises a heating means, a microcomputer control unit for controlling the heating means, and a voltage drop means for generating a power supply voltage for operating the microcomputer control unit. And a liquid crystal display, wherein a part of the voltage drop unit is formed by a light emitting unit, and the light emitting unit is configured as a backlight of the liquid crystal display.

Therefore, in this configuration, the power consumed by the voltage drop in the light emitting means is converted into light energy by the light emitting means, and the light energy by the light emitting means is used as a light source for a backlight of a liquid crystal display. Be utilized.

As a result, it is possible to effectively utilize the power consumption of the voltage drop means for obtaining the power supply voltage for operating the microcomputer control unit as a backlight light source, and to separately provide a dedicated backlight and a liquid crystal display part. The backlight function can be realized at lower cost without providing the driving power supply.

Further, the electric rice cooker according to the second aspect of the present invention is the electric rice cooker according to the first aspect of the present invention,
The light emitting means comprises a light emitting diode.

Therefore, the same operation as the electric rice cooker according to the first aspect of the present invention is realized by the light emitting means including the light emitting diode.

Further, the electric rice cooker according to the third aspect of the present invention is the electric rice cooker according to the second aspect of the present invention,
The liquid crystal display has a light guide plate interposed between a liquid crystal display element and a printed circuit board on which the liquid crystal display element is installed, while a plurality of the light emitting diodes are connected in series on the printed circuit board. Light is introduced from the side of the light guide plate to the lower surface of the liquid crystal display element via the light guide plate.

Therefore, according to this structure, the liquid crystal display element is installed on the printed board via the light guide plate below the liquid crystal display element, and a plurality of light emitting diodes connected in series on the printed board are connected to the light guide plate. The above-described operation can be realized simply at a low cost simply by being installed at the side portion.

[0016]

As described above, according to the electric rice cooker of the present invention, it is possible to provide a microcomputer-type electric rice cooker in which the display state of the liquid crystal display unit is easy to see even in a dark place, and which is low cost and consumes little power. Become.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration and operation of an electric rice cooker according to an embodiment of the present invention will be described below with reference to FIGS.

First, FIG. 1 shows a structure of a rice cooker main body of the electric rice cooker employing a heater as a heating means, for example.

The electric rice cooker according to the present embodiment is, for example, a so-called rice cooker of the so-called rice cooker type which serves both to cook rice and to keep heat. A container body comprising a bottomed cylindrical outer case 1 configured so that a rice cooker (inner pot) 3 can be set therein, and a lid unit 2 for covering the upper part of the outer case 1 is provided. It is configured.

The outer case 1 includes a bottomed cylindrical cover member 4 made of a synthetic resin, and a synthetic resin shoulder member 5 joined and integrated with the upper end of the cover member 4. Inside, a bottomed cylindrical inner case 6 for setting the rice cooker 3 so as to be able to be taken out is provided.

The inner case 6, for example made of a bottomed cylindrical metal plate, the upper side outer peripheral edge portion 6a against the lower surface of the peripheral portion 5a inner having a shoulder heater H ₃ of the shoulder member 5 coupled, heat retaining heater (sub-heater) H ₂ is provided on the outer circumferential surface vertically substantially central portion of the side wall 6b. Also,
At the center of the bottom wall 6c of the inner case 6, there is provided a center sensor 7 which is in contact with the center of the lower surface of the bottom 3a of the rice cooker 3.
Is provided.

The center sensor 7 is provided at the bottom 3 of the rice cooker 3.
A rice cooker set that functions as a rice cooker temperature detector and a rice cooker set detector that detects the temperature of a, and detects whether the thermistor T and the rice cooker 3 as the rice cooker temperature detector are set. A well-known sensor structure containing a reed switch (not shown) serving as a detecting means is employed.

Further, the upper side of the bottom wall 6c of the inner casing 6, provided with a cooking heater (main heater) H ₁ as rice vessel heating means so as to surround the thermistor T portion of the center sensor 7 A heater plate 9 is provided. The heater plate 9 is tightly adhered from the lower surface of the bottom portion 3a of the rice cooker 3 set in the inner case 6 to the side surface without any gap, and the heat transfer property of the bottom 3a of the rice cooker 3 and the side surface thereof is good. It is designed to be heated.

On the other hand, the lid unit 2 has an outer cover portion 10 made of synthetic resin constituting an outer peripheral surface thereof, an inner frame portion 11 inside the outer cover portion 10, and a lower surface side of the inner frame portion 11. The inner cover 13 is detachably provided to form a hollow structure as shown in the figure. The lid unit 2 is attached to the rear end side of the shoulder member 5 via a hinge mechanism 14 so as to be freely rotatable in the vertical direction. A lock mechanism 15 is provided which is engaged with a predetermined position on the side to maintain the closed state of the lid unit 2.

Reference numeral 16 denotes a steam release passage provided at the center of the lid unit 2, and reference numeral 17 denotes a steam release pipe detachably provided at a lower portion of the steam release passage 16 and having a function of returning to an end. is there.

Furthermore, the side in the space between the inner casing 6 and outer casing 1, the cooking heater H _1, insulation heater H _2, a microcomputer for performing energization control of the shoulder the heater H ₃ each A control board 24 having a control unit (see FIG. 6 described later) is accommodated.

On the upper end side of the front part of the shoulder member 5, there is provided an R-shaped operation panel 21 constituting a rice cooker operation section. For example, as shown in FIG. 3, a rice cooking menu (for example, white rice,
Menu switch 22, rice cooker switch 23, heat insulation switch 24, timer switch 25, which specifies fast-cooking, new rice, sushi, cooked rice, brown rice, rice porridge, etc.
A time / time setting switch 26a of the timer, a time / minute setting switch 26b of the timer, a cancel switch 27, a liquid crystal display 29 and the like are provided. Reference numeral 30a denotes a display time on the display surface of the liquid crystal display 29, and 30b
Are menu display sections for white rice, fast-cooked rice, new rice menu, etc., printed on the side of the display surface of the liquid crystal display 29;
Reference numeral 0c is a display index on the display surface side of the liquid crystal display 29, which is arbitrarily moved in correspondence with the menu display of the designated menu and is displayed oppositely.

On the other hand, on the back side of the operation panel 21, an operation board 32 provided with the liquid crystal display 29 and the various switch components is provided. The operation board 32
Is supported on an inclined support plate 41 integrated with the support housing 40 on the control board 24 side. The liquid crystal display 29 has a see-through lens 34 fitted to the panel surface opening of the operation panel 21 and a unit structure as shown in FIG. 4 and FIG. And a formed liquid crystal unit.

As shown, the liquid crystal unit comprises a liquid crystal display element 35, a light guide plate 36 provided below the liquid crystal display element 35, a liquid crystal display element 35 provided below the light guide plate 36, and a liquid crystal display. A liquid crystal printed circuit board 37 wider than the display element 36 and an upper side portion 37 of the light guide plate 36;
and a plurality of light-emitting diodes 45, 45,... as light-emitting means provided in parallel on the liquid crystal printed circuit board 37 in the vicinity of a.
They are detachably fitted and fixed on the control board 32 via the legs 38a and 38b of the support housing 38.

The plurality of light emitting diodes 45, 45... Of the liquid crystal unit are respectively connected in series in the forward direction on the liquid crystal printed circuit board 37, for example, as shown in FIG. A voltage drop means for forming a power supply voltage (+5 V) for operating the control unit 53 is formed.

[0031] That is, in FIG. 6, reference numeral 50 AC power (AC100V) for appliances, shoulder heater drive circuit 51 for driving the shoulder heater H _3, 52 micro operating power supply voltage of the computer control unit 53 (+5
V) A voltage regulator with an adjustable resistance value for adjusting and setting V), 53 is a microcomputer control unit for controlling rice cooking and heat retention, and 54 is a rice cooking heater H _{1 as} a main heater.
Main heater drive circuit for driving the 55 sub heater drive circuit, C _1, C ₂ is a smoothing capacitor for driving the heat retaining heaters H ₂ is the sub-heater, R ₁ is the voltage drop across the resistor, R ₂ is shunt resistor for current limiting, D ₁ is protection Taiodo,
D ₂ is a rectifier diode, TD _1, TD ₂ is a Zener diode that sets the relay operating voltage of the main heater driving circuit 54 and the sub heater drive circuit 55 side together with the resistor R _3, which are connected as shown, respectively.

Therefore, in this configuration, when the AC power plug of the electric rice cooker is connected to the AC power source 50,
Voltage regulator 52, the AC power source via a voltage drop across resistor R ₁ to the plurality of light emitting diodes 45, 45, ... 5
0, and a plurality of light emitting diodes 45,
45 light up and emit light. The light from the plurality of light emitting diodes 45 is introduced into the lower surface of the liquid crystal display element 35 via the light guide plate 36 of the liquid crystal unit shown in FIGS. The display surface of the display element 35 is displayed brightly. As a result, the display content of the liquid crystal display element 36 displayed through the see-through lens 34 of the operation panel 21 has a high contrast, and is clear and easy to see even in a dark place.

On the other hand, the voltage regulator 5 is determined by a combined resistance value of the resistance values of the resistors R ₁ and R ₂ and the forward resistance values of the plurality of light emitting diodes 45.
The potential at the point P of the input terminal 2 drops to a predetermined voltage value, and based on the dropped voltage value V, the voltage regulator 52 adjusts to a desired voltage (+5 V) required for the operation of the microcomputer control unit 53. To the microcomputer control unit 53.

[0034] As described above, in the first electric cooker of the present invention, a cooking heater H ₁ or the like as a heating means, microcomputer control unit該炊rice heater H _1, etc. Control 5
3, an electric rice cooker comprising: a voltage drop means for forming a power supply voltage for operating the microcomputer control unit 53; and a liquid crystal display 29. In the electric rice cooker, a part of the voltage drop means is used as a light emitting means. The plurality of light emitting diodes 45, 45,... Constitute the backlight of the liquid crystal display element 36 of the liquid crystal unit of the liquid crystal display 29.

Therefore, in this configuration, the voltage drop resistance R
_The power consumed by the voltage drop at the plurality of light emitting diodes 45, 45 ... forming a voltage drop means together with ₁ is converted into light energy by each light emitting diode 45, 45 ... Is effectively used as a light source for the backlight of the liquid crystal display 29.

As a result, compared with the case where the voltage drop means is formed only by the resistor, the power consumption in the voltage drop means for obtaining the power supply voltage for operating the microcomputer control unit 53 is eliminated, and the liquid crystal display 29 is used. The backlight function can be realized at a much lower cost than when a dedicated backlight and its power supply are separately provided in the portion.

Further, the liquid crystal display 29 has a light guide plate 36 interposed between a liquid crystal display element 35 and a liquid crystal printed circuit board 37 on which the liquid crystal display element 35 is installed. , 45... Are connected in series on the liquid crystal printed circuit board 37, and are respectively connected to the light guide plate 36 from the side of the light guide plate 36.
Light is introduced to the lower surface of the liquid crystal display element 35 through the.

Therefore, according to the configuration, the liquid crystal display element 35 is installed on the liquid crystal printed circuit board 37 via the light guide plate 36 below the liquid crystal display element 35, and a plurality of liquid crystal display elements 35 connected in series on the liquid crystal printed circuit board 37 are connected. Light emitting diodes 45 and 4
.. Are positioned on the side of the light guide plate 36 and are arranged in parallel, the above-described operation can be realized easily at low cost.

As a result, according to the electric rice cooker of the present invention, it is possible to provide a microcomputer type electric rice cooker in which the display state of the liquid crystal display 29 is easy to see even in a dark place, and which is low cost and consumes little power. .

(Modification) The plurality of light emitting diodes 45, 45...
However, the present invention is not limited to the case where they are provided in parallel on the upper side portion of the liquid crystal printed circuit board 37 as shown in FIG. 7. For example, as shown in FIG. It is also possible.

Each of the light emitting diodes 45, 45 can be of any light color.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a rice cooker main body of an electric rice cooker according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing an internal configuration of an operation panel unit which is a main part of the electric rice cooker.

FIG. 3 is an enlarged front view showing a configuration of a panel surface of an operation panel unit which is a main part of the electric rice cooker.

FIG. 4 is an enlarged plan view of a liquid crystal unit of a liquid crystal display, which is a main part of the electric rice cooker.

FIG. 5 is an enlarged sectional view of the liquid crystal unit.

FIG. 6 is an electric circuit diagram showing a configuration of a control circuit around a microcomputer control unit of the electric rice cooker.

FIG. 7 is an enlarged plan view showing a configuration of a modification in which a configuration of a main part of the electric rice cooker according to the embodiment of the present invention is modified.

[Explanation of symbols]

1 is an outer case, 2 is a lid unit, 3 is a rice cooker, 6 is an inner case, 21 is an operation panel, 29 is a liquid crystal display, 32
Is an operation board, 34 is a see-through lens, 35 is a liquid crystal display element,
36 is a light guide plate, 37 is a liquid crystal printed circuit board, and 45 is a light emitting diode.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-289426 (JP, A) JP-A-62-159618 (JP, A) JP-A-8-313902 (JP, A) 19115 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) A47J 27/00

Claims (3)

(57) [Claims] 1. An electric rice cooker comprising a heating means, a microcomputer control unit for controlling the heating means, a voltage drop means for forming a power supply voltage for operating the microcomputer control unit, and a liquid crystal display. An electric rice cooker wherein a part of the voltage drop means is formed by a light emitting means, and the light emitting means is configured as a backlight of the liquid crystal display. 2. The electric rice cooker according to claim 1, wherein the light emitting means comprises a light emitting diode. 3. A liquid crystal display has a light guide plate interposed between a liquid crystal display element and a printed circuit board on which the liquid crystal display element is installed, while a plurality of light emitting diodes are connected in series on the printed circuit board. The electric rice cooker according to claim 2, wherein light is introduced from a side portion of the light guide plate to a lower surface of the liquid crystal display element through the light guide plate.