JPH0830580B2 - Cooking device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating and cooking device having a liquid crystal display unit, and more particularly to lighting control of an illumination light source on the back surface of a liquid crystal.

2. Description of the Related Art Conventionally, in a cooking device having a digital control unit, such as a microwave oven using a micro computer, the cooking performance is improved by applying a temperature sensor, a humidity sensor, or a humidity sensor, and the number of menus that can be achieved by automatic cooking is improved. Has also increased. Therefore, the number of menu keys arranged on the operation panel is increased and the operation is complicated, and a fluorescent display tube or the like is used for the display unit, but the amount of information displayed is small and it is convenient.

Therefore, a method of using a liquid crystal display to improve the operability by displaying only necessary information such as displaying the menu name for each cooking category and further providing an illumination light source on the back surface of the liquid crystal to improve the visibility can be considered. . As such an illumination light source, a fluorescent lamp, a tungsten bulb, an EL surface emitting element, or the like is used. If such an illumination light source is constantly turned on, of course, there is a problem in terms of its life, and as a remedy therefor, for example, as disclosed in JP-A-60-174437, the illumination light source is turned on during cooking setting and cooking. Methods such as limitation are taken. Furthermore, as in Japanese Patent Laid-Open No. 60-196522, a light source for a display unit, which is provided with a plurality of light sources and is constantly lit, and a light source for a display unit, which is lit only during cooking setting or cooking, have different life spans. It is improving.

The problem to be solved by the invention However, limiting the illumination of the liquid crystal display during cooking makes it impossible to display the clock, which has an important weight as an additional function of the heating device. The value is greatly reduced. Further, having a plurality of light sources raises the cost and further restricts the physical space. Therefore, it is not necessary to have the same brightness in the light and dark, but it has been the same in the past.

The present invention solves such a conventional problem, and an object of the present invention is to improve the reliability of the illumination light source on the back surface of the liquid crystal and to obtain appropriate visibility.

Means for Solving Problems The present invention provides a heating source for heating an object to be heated, a controller for controlling the heating source, input means for inputting heating conditions to the controller, and irradiation from the rear surface for displaying a clock and a menu. A liquid crystal display unit, a light source for irradiating the rear surface of the liquid crystal display unit disposed on the back surface of the liquid crystal display unit, a light amount control means for controlling the light amount of the light source, and a liquid crystal display unit for collecting the brightness of external light. Provided with a daylighting part provided in part, and an external light measuring means for measuring the brightness of the external light that has been taken,
The light quantity of the light source is made variable by the light quantity control means for controlling the light quantity of the light source on the basis of the signal from the external light measuring means.

Function The present invention is based on the above configuration, the brightness of the room is taken in from the daylighting section and converted into an electric signal by the photoelectric conversion element, and a fluorescent lamp or a tungsten light bulb or the like is provided so as to have a predetermined illumination intensity according to the electric signal. The power supplied to the light source is controlled to increase the lighting intensity when the room is bright and weak when the room is dark, and the lighting unit is provided on the liquid crystal display to save space and reduce the number of parts. .

EXAMPLE FIG. 1 is a perspective view showing a part of a high frequency cooking apparatus of the present invention with a part cut away.

 The configuration of the heating and cooking device of the present invention will be described.

A door 2 and an operation panel 3 which can be freely opened and closed are provided on the front surface of the main body 1.
Are provided. The operation panel 3 is provided with a start key 4, a cooking selection key 5, and a liquid crystal display 6 for displaying numbers, categories, menus, and time. Further, a part of the liquid crystal display part 6 is provided with a daylighting part 7 for measuring the brightness of the room in which the main body 1 is installed, and outside light enters the inside of the main body 1 via the daylighting part 7. ,
Its brightness is measured. Inside the main body 1, there is a tungsten light bulb 8 on the back of the liquid crystal display unit 6, and a hood 9
Therefore, the illumination light is uniformly applied to the liquid crystal display unit 6. Tungsten bulb 8 is a lead wire
The light quantity is guided to the light quantity control section by 10 and the light quantity is controlled by the controller 12.

 FIG. 2 is a sectional side view of the operation panel 3.

Liquid crystal display 6, start key 4, cooking selection key 5
A keyboard 11 and a controller 12 having various switches such as a switch, a printed circuit board 17 on which various electronic parts such as a microcomputer (hereinafter referred to as a microcomputer), a triac 13, an operational amplifier 14, a keyboard connector 15, and a low voltage transformer 16 are mounted in this example. It is held by a resin base body 18, which is a holder for the operation panel 3. Further, as described above, the tungsten light bulb 8 is arranged on the back surface of the liquid crystal display portion 6, and the light from the tungsten light bulb 8 is condensed by the hood 9 to illuminate the liquid crystal display portion 6 from the back surface. This irradiation light is divided into light that is transmitted and emitted to the outside and light that is not transmitted and is blocked depending on the electrical state of the liquid crystal cell 19 inside the liquid crystal display unit 6. Therefore, the display pixels written on the character sheet 20 are separated into the transparent portion and the blocking portion, and as a result, the display disappears or is displayed. An electric signal for changing the electric state of the liquid crystal cell 19 is given from the microcomputer 12 via the lead pin terminal 21.
The microcomputer 12 has a built-in drive function for liquid crystal display. Next, the external light from the lighting unit 7 is received by a photoelectric conversion element such as a photocell 22, converted into an electric signal according to the amount of the light, passes through the photocell lead wire 23, and is transmitted to the printed circuit board 17 by the signal connector 24. The signal is amplified by the operational amplifier 14 and input to the microcomputer 12 as an electric signal according to the amount of external light. Based on this signal, the microcomputer 12 controls the phase angle of the gate signal of the triac 13 according to the pre-programmed processing procedure of the microcomputer 12 to change the power supply amount to the tungsten light bulb 8 and, as a result, to the liquid crystal display unit 6. It controls the amount of illumination light. That is, in FIG. 1 and FIG. 2, the intensity of the illumination light source of the liquid crystal display unit 6 is variably controlled according to the brightness of the light detected from the outside through the lighting unit 7.

FIG. 3 shows a block diagram of a heating source and a light source control circuit of the heating and cooking apparatus of the present invention.

The magnetron 25 is on / off controlled by the high frequency power control unit 26 to execute a predetermined high frequency heating cooking. The speaker 27 emits a key input sound and a cooking end sound, and is driven by the microcomputer 12. Controller 12 (microcomputer)
Is the setting of cooking, start, stop, and cancellation according to the key input from the keyboard 11 and the analog signal from the photocell of the photoelectric conversion element 22 is input through the external light measuring unit 14, and the amount of external light is measured. The amount of power supplied to the illumination light source 8 of the liquid crystal display unit 6 is controlled to a predetermined value by changing the control signal to the light amount control unit 13 according to the brightness. Further, the controller 12 (microcomputer) controls the magnetron 25 via the high frequency power controller 26 in response to the detection signal from the humidity sensor 28. The controller 12 (microcomputer) is a microcomputer equipped with a liquid crystal driving circuit and an output port. Reference numeral 29 is an oscillator circuit for the clock pulse of the microcomputer 12.

The light quantity control of the illumination light source will be described based on Table 1.

As shown in Table 1, the light quantity control modes of this embodiment are I and II.
And two types. That is, the brightness of the incident light from the lighting unit is divided into the daytime brightness and the nighttime brightness at which almost no brightness of the incident light can be detected.
The latter is called Mode II. In Mode I, the power supplied to the illumination light source is set to 100% in order to brighten the liquid crystal display unit against the brightness of external light. On the other hand, in Mode II, the brightness of the liquid crystal display unit is reduced by the darkness of external light. Even if it is lowered, good visibility is maintained, so the power supplied to the illumination source is 50%.
And the lighting is less than half the brightness.

By the way, the daylighting section 7 of this embodiment is formed on a part of the liquid crystal display section 6, and this daylighting section 7 is provided on the operation panel 3.
Even if it is installed in the other part above, it does not pose any problem to the gist of the present invention. However, by integrally forming the daylighting section 7 and the photoelectric conversion element 22 in the liquid crystal display section 6, the space efficiency of the operation panel 3 can be improved.
Further, the photoelectric conversion element 22 is formed on the liquid crystal display unit 6, and its signal is drawn out by a transparent conductive pattern, and the lead pin terminal 21 is connected to the conductive circuit pattern on the printed circuit board 17. Improvement of sex,
Also, the overall configuration can be simplified.

The photoelectric conversion element 22 is not a photoconductive element such as a photocell, but a simple element such as a photodiode is used to simply identify whether it is daytime or nighttime, and it is also possible to control the power of the illumination light source accordingly. it can.

Effects of the Invention According to the heating and cooking device of the present invention, the following effects can be obtained.

(1) The brightness of the light source for the liquid crystal display is switched according to the brightness of outside light. 100% of the lighting power is used during daytime and 50% of the lighting power at night. By illuminating, the life of an illumination light source such as a tungsten bulb can be dramatically improved.

(2) Also, even in a dark room at night, by illuminating with the same brightness of the light source as in the daytime, the display quality of the liquid crystal display part shines strangely in a dark room, and the display quality is adversely reduced. As a matter of fact, the visibility of the liquid crystal display unit can be greatly enhanced by halving the lighting at night in the daytime.

(3) By reducing the power to the illumination light source at night to half or less during the daytime, it is possible to reduce power consumption as a light source and save power.

(4) By constructing the lighting unit and the photoelectric conversion unit for the outside light integrally with the liquid crystal display unit, not only the space of the heating device as a whole can be saved but also the assembling workability can be improved and the number of parts can be reduced. Therefore, it is possible to realize a large cost reduction.

[Brief description of drawings]

FIG. 1 is a partially cutaway external perspective view of the heating and cooking apparatus of the present invention, FIG. 2 is a sectional side view of an operation panel portion of the heating and cooking apparatus of the present invention, and FIG. 3 is a heating source and a light source of the heating and cooking apparatus. A block diagram of the control circuit of is shown. Table 1 is a table showing the relationship between the brightness of the lighting unit and the power supplied to the illumination light source. 1: body, 2: door, 3: operation panel, 6: liquid crystal display part, 7: daylighting part, 8: tungsten bulb, 9: hood, 11: keyboard, 12: controller (microcomputer), 13: light intensity control element,
14: Ambient light measuring section, 15: Keyboard connector, 16: Low voltage transformer, 17: Printed circuit board, 18: Tungsten bulb, 19: Liquid crystal cell, 20: Character sheet, 21: Lead pin terminal, 22: Photoelectric conversion element, 23: Photocell lead wire, 24: signal connector, 25: magnetron, 26: high frequency power controller, 27: speaker, 28: humidity sensor, 29: clock oscillation circuit.

Claims (1)

[Claims] 1. A heating source for heating an object to be heated, a controller for controlling the heating source, an input means for inputting heating conditions to the controller, a liquid crystal display section for irradiating from the back side for displaying a clock and a menu, and the liquid crystal. A light source for irradiating the back surface of the liquid crystal display unit arranged on the back surface of the display unit, a light amount control means for controlling the light amount of the light source, and a lighting unit provided in a part of the liquid crystal display unit for collecting the brightness of external light. , And external light measuring means for measuring the brightness of the external light,
A heating and cooking apparatus characterized in that the light quantity of the light source is made variable by the light quantity control means for controlling the light quantity of the light source based on the signal from the external light measuring means.