CN1684602A - Improved personal care device with thermal feedback and operating state display - Google Patents

Abstract

A personal care device, such as a hair dryer, has a thermal feedback sensor positioned adjacent the outlet of the device to automatically reduce the thermal power output when a predetermined threshold temperature is reached. The device also includes a graphical and numerical display for indicating the operational status of the device.

Description

An improved personal care device with thermal feedback and working status display

technical field

The present invention relates to personal care devices, and more particularly to personal care devices having a heating element and a motor driven fan. The invention also relates to a hair care device with a liquid crystal display. More specifically, the present invention relates to, but is not limited to, hair dryers and air heaters with over-temperature protection and operating status display.

Background technique

A personal care device having a heating element and a motor-driven fan, typically used for added personal comfort or personal grooming.

For example, hair care devices such as hair dryers or curling irons, which have a heating element and a motor-driven fan, provide a simple, localized heat source that forces air to blow out warm air for conditioning or short-term styling. In such applications, a wide range of thermal power levels and fan speeds is often required to meet specific personal comfort and grooming requirements. For example: drying and styling wet hair requires a high heat power level and high fan speed, while general hair styling requires a low or medium heat power level and medium fan speed.

Similarly, for a fan heater, a high thermal power level and high fan speed are required to quickly warm a cold space, while a moderate or low thermal power level and moderate fan speed are required to maintain a relatively comfortable temperature and humidity in the room. fan speed.

To accommodate a wide range of operating power requirements, the heating elements incorporated in such personal care devices must be capable of operating over a wide range of power outputs. The standard operating power ratings of such heating elements generally range from several hundred watts to 2000-3000 watts.

Such personal care devices typically include a main housing which is an air channel having an air inlet and an air outlet. The heating element is typically positioned midway between the air inlet and outlet so that the downstream air is warmed or warmed before leaving the device for hair styling or other related applications. These personal care devices typically provide user control interface devices, such as control buttons or rocker switches, with multiple heat power levels and fan speed settings. Thermal power level settings are generally divided into discrete levels, and then calibrated assuming that the air passes through the air channel unimpeded. Under this assumption, the hot air discharged from the nozzle or air outlet according to the preset setting will be at a relatively stable, convenient and safe temperature. However, this is not always the case, when the outlet of the airflow channel is blocked, the temperature of the heating element is sufficiently increased. For example, when the air outlet or nozzle is placed too close to the user's head or to other obstructing surfaces. Airflow through the airflow channels is unnecessarily impeded resulting in insufficient airflow, which increases the temperature of the heating element, which can lead to personal injury or fire. Therefore, there is a need for an improved safety protection device for such personal care devices, which reduces or avoids the risk of injury and fire caused by the use of such devices.

In addition, such personal care devices provide users with selectable switches that are divided into discrete levels for setting operating conditions. Such control switches are usually in the form of rocker switches and do not provide users with any Useful, indicative operational information. Therefore, it is necessary to deliver useful information to users through an improved device.

Contents of the invention

Correspondingly, the object of the present invention is to provide a personal care device with a safety protection device, such as: a personal care device such as a hair dryer, a hair dryer, a hair dryer and a heater, so as to reduce the occurrence of unfavorable or improper working conditions of the device. risk of personal injury or fire due to overheating.

Another object of the present invention is to provide users with an improved personal care device, which has a solution and a device for intuitively conveying the working status of the device to the user, so as to enhance the interactive operation between the user and the device. The most basic object of the present invention is to provide an improved personal care device, such as a hair dryer, hair dryer, curling iron, air heater, etc., to provide another choice for the public.

According to the first object of the present invention, there is provided a personal care device, such as a hair dryer or a heater, comprising: a main casing; a motor; a fan driven by a motor; a heating element; a control device; a thermal induction device; The main casing is an airflow channel with an air inlet and an air outlet; the heating element is arranged in the middle between the air inlet and the air outlet; the thermal induction device is arranged At a position close to the air outlet, and provide temperature information to the control device; the control device includes a memory for storing temperature information; The device of temperature information and pre-stored temperature information. When the temperature corresponding to the received temperature information exceeds a predetermined threshold (threshold), the control device reduces the thermal power output of the heating element according to a predetermined manner.

According to the second object of the present invention, there is provided a personal care device, such as a hair blowing cap, a hair dryer, a hair curler and a warm air blower, the main housing of the personal care device is provided with a display device to display the instant operation of the device state.

Description of drawings

Below in conjunction with accompanying drawing, describe the present invention in detail by preferred embodiment of the present invention:

Fig. 1 shows the mixed circuit schematic diagram of the total circuit of the general circuit arrangement of a preferred embodiment of a hair dryer, wherein the forward (fronted) sensing circuit is connected with a microcontroller for automatic feedback control of the heat power output of the hair dryer;

The example shown in the circuit schematic diagram of Fig. 2 is the overall more detailed circuit arrangement of the hair dryer in Fig. 1;

Fig. 3 is a schematic circuit diagram showing the overall circuit arrangement of the second preferred embodiment of the hair dryer of the present invention, which includes the first preferred embodiment of the display device for indicating the working state of the hair dryer;

Fig. 4 shows a series of display changes as an example for the screen display of Fig. 3;

Figure 5 is a general circuit diagram showing another preferred embodiment of the control and display circuit of the hair dryer in Figure 1;

Figure 6 shows an example of a series of graphic display designs for the display device in Figure 5;

Fig. 7 is a partial exploded view for explaining the hair dryer of the present invention.

Detailed ways

The hybrid circuit and component schematic diagram of FIG. 1 and the partial exploded view of FIG. 7 show an example of application, namely, the thermal sensing device is used for automatic thermal feedback to control the operation of the heating element of the hair dryer 10. The circuit arrangement includes: a thermal induction forward circuit 100, a synchronous circuit 110, which is synchronized with the AC power connected to the hair dryer, and the control device 120 is a microcontroller unit (MCU: micro-controller unit) in this embodiment, a first A heating element 130 is connected in parallel with a second heating element 140 and controlled by respective switches. As will be apparent from the following description, the heat output of the hair dryer can be flexibly and precisely varied by selectively turning on a single heating element at different moments in the AC power cycle.

Broadly speaking, the thermal sensing device in this embodiment is a negative temperature coefficient device (NTC: negative temperature coefficient), which is arranged at a position where it is easy to detect the immediate working temperature of the hair dryer 10 . The output end of the heat sensing device is connected to an input end of the microcontroller unit 120 to provide the MCU with sensed temperature information for corresponding work. The thermal sensing element, that is, the NTC element in this embodiment, is connected to the bias circuit, so that the change of the electrical characteristic of the NTC element can be converted into an electrical signal usable by the MCU.

In this example, one end of the NTC device is connected to a voltage line (VCC). The other end of the NTC is connected to ground through a resistor (R shown in Figure 1). The node interconnected with the NTC device and the resistor R is an output node of the NTC device, and the NTC output node is fed into an input terminal of the MCU. A capacitive device (C shown in Figure 1) is connected across the resistor R as a delay buffer to prevent oversensitivity to ambient temperature changes or transient disturbances. The NTC element 101 is essentially a resistor, and the resistance value of the resistor decreases as the temperature rises, and in the NTC device, an increase in temperature will result in a decrease in resistance value. Therefore, an increase in output voltage is detected at the output node of the NTC device. This phenomenon provides useful control information for the MCU to determine the immediate downstream air temperature.

Pre-calibrate or tabulate the electrical characteristics of the NTC part 101, for example, the relationship between the resistance and temperature of the NTC part, the MCU can directly measure the relationship between the output voltage and the detected temperature, and use it to prevent the blower from overheating. For example, relevant information corresponding to the specific thermal power and fan speed settings of the hair dryer, such as the maximum temperature threshold and the voltage output by the NTC output node, is stored in a storage device that has an access relationship with the MCU. Once the temperature indicated by the output voltage of the NTC device exceeds the temperature threshold, the microcontroller sends instructions to the control circuit to reduce or even shut down the thermal power output.

In this particular embodiment, the use of a lossless thermal power output control method is a convenient and preferred example. In this scheme, the first heating element and the second heating element can be turned on and off separately in a certain part of the AC power supply, and the thermal power output can be reduced by selectively turning on the first heating element and/or the second heating element. In this embodiment, a more versatile, flexible and precise thermal power output variation scheme can be provided by using a parallel combination of two individually switchable heating elements.

For example, with two heating elements turned on consecutively throughout the cycle of AC power, the thermal power output level can reach a maximum value. Selectively turn on or turn off one or two heating elements in a certain cycle of the AC power supply, which can reduce the thermal power output. For example, the heat output can be reduced by: turning on the first heating element in the positive half cycle of the AC power supply, and turning off the second heating element only in the negative half cycle of the AC power supply. The first and second heating elements are selectively turned on at various possible combinations of start times according to the AC power cycle to reduce overall power output.

In order to reduce the unfavorable harmonics generated by selectively turning on the first and second heating elements, the power consumption level should be as uniform as possible during the whole cycle of the AC power supply. However, in the cycle of AC power, if the technology of power cutting is used, it will lead to poor power consumption or interruption, and generate strong harmonics. Therefore, it is necessary to turn on the heating element evenly during the cycle of the AC power supply. To achieve this purpose, the input end of the synchronization circuit 110 is connected to the AC power supply, and the output end is connected to the MCU 120 . The synchronous circuit provides timing information of the AC power source to determine the proper start-up time of the heating element at or near the zero crossing point of the AC power source, or other points, thereby reducing harmonics and other adverse effects. In the preferred embodiment, triacs are used, and the synchronization circuit provides useful triggering and timing information for activating the triacs.

In this special embodiment, the power reduction is achieved by selectively turning off the power, or selectively turning on and off the heating element at an appropriate time, which provides a solution for power reduction without loss, and the start-up time control of the heating element is very important for reducing Unfavorable harmonics are important. Of course, loss schemes with reduced loss of thermal power can also be used. In the thermal power loss reduction solution, a loss element, such as a load resistor, is usually connected in series with a heating element or a combination of heating elements, and additional or redundant electric power is consumed through the loss element. In this loss scheme, the problem of unfavorable harmonics is usually not serious, the required heating element start-up time scheme is not critical, and synchronous circuits may not be needed.

A more detailed circuit diagram of the circuit in FIG. 1 is shown in FIG. 2 . As shown in the figure, the thermal sensing circuit 100 , the first heating element 130 , the second heating element 140 and the synchronization circuit 110 connected to the MCU 120 . In addition, the user control interface device includes: a fan speed setting button 150 and a heating level setting button 160 . In addition, the display device 170 for indicating the working state of the hair dryer is connected to the output terminal of the MCU 120, and the corresponding working state is transmitted by the MCU 120 and displayed on the display device. A DC motor 180 forces the air to flow from the blower, and a bridge rectifier to provide the necessary DC power. A heating element 190 is also attached between the AC power supply and the rectifier bridge to adjust or slow down the voltage difference between the rated input voltage of the rectifier and the output terminal of the AC power supply.

With reference to the hair dryer in Figure 7, the work of the hair dryer will be described. As shown in FIG. 7 , the hair dryer 10 includes: a main casing with a barrel 12 and a handle 13 ; a first heating element 130 ; a second heating element 140 ; For user convenience, the user control interface device includes: a fan speed control button and a heating level setting button, preferably the user control interface device is arranged outside the handle part. The barrel forms an upstream air inlet 14 near the handle portion and a downstream air outlet 15 at the other end of the barrel. The heating element is preferably arranged in the middle between the air inlet 14 and the air outlet 15 . In this embodiment, the thermal induction device or NTC element 101 is arranged near the air outlet 15. During normal operation, the temperature of the exhausted air rises; under unfavorable working conditions, the temperature of this position will rise rapidly. According to the predetermined fan speed, when the heat power control button is set to a predetermined level, under normal operation, the warm air blown out of the air outlet will usually not exceed the temperature threshold. Such temperature thresholds are typically characterized by an electrical parameter characteristic of the thermal sensing circuit. In this embodiment, the maximum voltage output at the output node 102 of the NTC represents the temperature threshold.

When the warm or hot air from the blower hits the surface of the obstacle, the temperature of the heating element rises due to insufficient air circulation or heat dissipation. If the blower continues to be obstructed, it may cause the heating element to become red hot and cause injury to the user or cause a fire. In this embodiment, when a signal indicating an overheating is detected, the microcontroller 120 will correspondingly reduce the heat output to avoid such danger. If in the subsequent detection, if the MCU detects that the output voltage of the thermal sensor returns to a safe level, normal thermal power output will be resumed. As mentioned above, although the lossless scheme is the preferred scheme for energy conservation and environmental protection, either the lossy scheme or the lossless scheme can reduce the thermal power output. Of course, thermal feedback control topologies can be used in both lossy and lossless schemes.

As shown in Figure 3, it is a second control and display circuit of a preferred embodiment of the hair dryer. The blower circuit includes: a motor 280 in parallel with a switchable shunt resistor controlled by switch SW2 250 for speed variation; and a switchable ionization circuit that provides ionized warm air for hair styling . Also shown is a heating level control switch SW1 260, which can switch and control multiple discrete heating power level settings. The working state of switch SW2 250, ion circuit 261 and thermal power level switch SW1 is connected with the input end of MCU. The output end of the MCU is connected with a display device 270 for displaying the working state of the hair dryer.

For example, when the shunt switch SW2 250 is closed and the motor speed is low, the SW2 terminal is pulled high. Since there is a reverse circuit connected between the input terminal PB3 and the switch SW2 250, the input terminal PB3 of the MCU220 can detect a low signal. Similarly, the MCU can detect whether the ionization circuit is running by detecting whether the series switch "IONIC SW" 262 is closed or disconnected. When IONIC SW 262 is closed and the terminal is at high potential, MCU220 input terminal PB4 will detect a low signal. Similarly, when the thermal power level selection switch SW1 260 is set to a high thermal power level corresponding to high power output, the input terminal PB1 of the MCU 220 detects a low potential, while the other input terminal PB0 maintains a high potential. On the other hand, when the switch SW1 260 is set to a low thermal power level, the input terminal PB0 of the MCU becomes a low potential, and the input terminal PB1 maintains a high potential. Therefore, by scanning the states of the ports PB0 and PB1, the MCU can determine the real-time thermal power level setting, and send relevant working state information to the display device. The display device may be a liquid crystal display (LCD: Liquid Crystal Display) or other suitable displays, and includes a plurality of input nodes for connecting to MCU output nodes.

By properly configuring and programming the MCU, the working status or parameters of the hair dryer detected and monitored by each input port of the MCU can be converted into control signals at the output port and displayed on the device display. Figure 4 shows a series of possible information displays that may be displayed on the display device to reflect the operating status of the hair dryer.

For example, in this best hair dryer, there are two speed settings and two heat power level settings, and an additional cool air setting for cold air only, for a total of five combined settings. The working state of the hair dryer is displayed on the display device.

In the preferred embodiment of the display device, taking the graphic display device in the leftmost column as an example, the first row displays corresponding to the working setting value 1-5; the second row is used to display the current thermal power level setting, expressed in digital form Wattage, the third line is used to indicate whether the negative ion distribution circuit is in operation. On the right side of the display device, there are 8 indicators for indicating the temperature of the gas blown by the blower. Usually, when more indicators light up, it means higher temperature, and when all 8 indicators light up, it means that the hair dryer has been working at the highest working temperature.

As shown in the second row of display device in Figure 4, most of the display changes are the same as in the first column above, except that 8 indicators are used to indicate the fan speed of the blower, and the meanings expressed by the changes of the display device are the same as those in the first column The display device is the same. Since there are only two power settings, the 8 indicators are divided into two display areas, each containing 4 indicators. When the hair dryer is running at high speed, all 8 indicators are on. On the other hand, when the dryer is running at low speed, only the first four indicators light up. Therefore, it can be seen that the display device can be flexibly arranged to provide ideal information beneficial to the user. In addition to displaying functional parameters, other information, such as the manufacturer's trademark, logo or other proprietary signs 500, etc. can also be displayed on the same display device, or displayed on the main housing of the hair dryer through LCD, LED or other suitable display devices .

Figure 5 and Figure 6 show a hair dryer, which has a second preferred control device and a display device 370 of the hair dryer. In this hair dryer, the usual basic functions of the hair dryer are no longer described in detail. Contained in the hair dryer: a plurality of stepwise or progressive control switches SW1-SW6, which are divided into three groups, namely SW1 and SW2, SW3 and SW4, SW5 and SW6. For example, switches SW1 360 and SW2 correspond to heating element control, SW3 and SW4 350 correspond to fan speed control, and SW5 and SW6 361 correspond to ionizer control. Press SW1, MCU will gradually increase thermal power output before SW1 is released. On the other hand, when SW2 is pressed, the MCU will control the heating element to reduce the thermal power output before SW2 is released. When neither SW1 nor SW2 is pressed, the hair dryer continues the current working state. Likewise, after pressing SW3, the MCU keeps increasing the fan speed until SW3 is released or until the maximum speed is reached. The same is, after pressing SW4, unless the motor is stopped or the switch is released, the MCU will keep reducing the fan speed. The ionization control means SW5 and SW6 generally work under the same principle.

In this preferred embodiment, press the control switch to realize the matrix formed by the input terminals 20-24 of the MCU, wherein the port 20 corresponds to the heating element control, the port 21 corresponds to the fan speed control, and the port 22 corresponds to the ion generation device control. Likewise, MCU port 24 corresponds to a rising adjustment indication, and port 23 corresponds to a falling adjustment. Of course, other settings can also be made. By combining controls in a matrix form, user needs to change work states can be continuously monitored and satisfied. A different form of display is provided in the preferred embodiment. The display in this embodiment includes a liquid crystal display device, which has two groups of bar displays respectively indicating speed and temperature, and also includes an ion generator trigger display. The liquid crystal display device is connected with the MCU, and the MCU provides a signal according to the detected working state, and the speed and temperature display bar provides a multi-level indicator corresponding to the signal.

The three columns shown in Figure 6 show the possible changes of the LCD information display, and the LCD information display is divided into speed display, temperature display and ionization display by column.

Through the description of the present invention through the above several preferred embodiments, it can be seen that the embodiments are only used to illustrate the present invention, not to limit the spirit and scope of the present invention. The above content is used to illustrate the general principle and spirit of the present invention. In particular, for those skilled in the art, all obvious minor changes or modifications, including all improvements based on the present invention, should be regarded as falling within the scope of the present invention. Furthermore, although the invention has been described in terms of a hair dryer having a lossless power reduction scheme, it can be seen that the invention can also be applied to other hair dryers and heaters, with or without modification, regardless of the mode of power reduction scheme.

Claims (8)

1. A personal care device, such as a hair dryer, or a hot air blower, is characterized in that it includes: a main housing, a motor, a motor-driven fan, a heating element, a control device, a thermal induction device, The main housing is an airflow channel with an air inlet and an air outlet; the heating element is arranged between the air inlet and the air outlet; the thermal induction device is arranged at The position close to the air outlet is used to provide temperature information to the control device; the control device includes a memory for storing temperature information, and the control device also includes a memory for comparing the thermal sensor The temperature information received by the device and the pre-stored temperature information device, when the temperature corresponding to the received temperature information exceeds a predetermined threshold, the control device reduces the thermal power output of the heating element according to a predetermined method. 2. The device according to claim 1, wherein said heat sensing device comprises a negative temperature coefficient device. 3. The apparatus according to claim 1, wherein the predetermined manner comprises: a plurality of predetermined settings corresponding to a plurality of predetermined discrete heat power and fan speed settings. 4. The device according to claim 1, further comprising: a display device, which is arranged on the main housing and used to indicate the real-time working status of the device. 5 . The device according to claim 4 , wherein the display device includes graphic signs for displaying the working status of the device, and the working status includes: fan speed level and ion hair care trigger. 6. The device according to claim 4, wherein the display device includes a digital display for displaying the real-time power of the heating element. 7 . The device according to claim 6 , wherein the display device further includes graphic signs for displaying the speed level of the fan of the device and the working status of starting ion hair care. 8 . 8. The device according to any one of claims 4 to 7, wherein the display device comprises a liquid crystal display.

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