JPH10333766A - Portable information terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heat a portable information terminal for preventing the display of a display part from being made unclear, the printing of a printer part from being made defective, or the output of a battery from being deteriorated due to low temperature at the time of using this portable information terminal in low temperature before and after surrounding temperature -20 deg.C. SOLUTION: A heating vessel 7 for housing a portable information terminal is provided with a heater 5, and the heat of the heater 5 is directly applied or applied through a heat pipe 6 to a display part 3 and a printer part 4 of a portable information terminal main body 1. Thus, the portable information terminal can be heated, the display part 3 of the portable information terminal can be made clear, the printing of the printer part 4 can be made satisfactory, and the output of a battery can be prevented from being deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a portable information terminal which can be used without deteriorating its function even when the outside air temperature is as low as about -20.degree.

[0002]

2. Description of the Related Art When the outside air temperature drops to about -20.degree. C., the temperature of the main body of the portable information terminal becomes 0.degree. C. or less, the display section becomes unclear, the printer section has poor printing, and the battery output is low. Conventionally, in order to prevent the temperature from dropping, the portable information terminal itself is wrapped in a blanket or the like to prevent the temperature from becoming 0 ° C or less, or a heat storage mat in which a heat storage agent in the mat is heated in advance by an external heat source. Use,
Attempts were made to heat the whole unit, but the efficiency was poor, and there were problems that a number of the heat storage mats were required and that the heat storage mat could not be used for a long time. Japanese Patent Application Laid-Open No. Hei 6-333100 discloses a known example relating to heat retention of a terminal device, Japanese Patent Application Laid-Open No. 8-140274 discloses a known example relating to heating of a battery of a portable device, and Japanese Patent Application Laid-Open Publication No. There is 250092 gazette.

[0003]

[0006] Portable information terminals are widely used in the fields of distribution, manufacturing, and service because of their excellent portability as portable information devices. In particular, it has the feature that it can be operated while being held in hand and the place of use is not limited.

[0004] However, in outdoor areas in winter in a cold region, the ambient temperature is severe, such as about -20 ° C, and in the case of a liquid crystal display device, the display is unclear due to the low temperature. Further, in the printer unit using a thermal printing method or thermal paper, there is a problem that printing is poor due to low temperature, and output of a battery is reduced due to low temperature.

Furthermore, if a heat storage mat is used to keep the body warm, it cannot be used for a long time due to the limited heat storage capacity, and the temperature of the heat storage mat must first be raised first. There is a problem that consumption of heat becomes large. If a heater is used for the heat storage mat disregarding this, a power source is separately required, and the power source cannot be carried, so that there is a problem that it cannot be used for a long time.

Further, when a heat storage mat is heated by a heat pipe and a heater is used as a heat source of the heat pipe,
Similar to the above, a separate power supply is required, and the power supply cannot be carried, so that there is a problem that it cannot be used for a long time.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems.

That is, a heater is provided in a heat retaining container for accommodating a portable information terminal, and the heat of the heater is directly or via a heat pipe, a display unit, a printer unit, etc. of the portable information terminal body. Thus, the display section, the printer section and the like of the portable information terminal can be forcibly heated. As a result, even when the ambient temperature drops to about −20 ° C.,
It can be heated to a temperature of not less than ° C., eliminates blurring of the liquid crystal in the display unit, and eliminates printing defects in the printer unit.

Further, in another invention, the heater is constituted by a heating agent comprising a mixture of an oxygen supply agent and a combustible agent or a heating agent which generates heat upon contact with air, so that a heat source is externally provided for a predetermined time. The function of the heater can be exhibited without supplying it. This eliminates the use of a heater as a heat source or the use of a heat storage mat in which a heat storage agent in the mat is heated in advance by an external heat source.

Further, in another aspect of the invention, a heat transfer fin is provided which is in thermal contact with a display unit, a printer unit, etc., a recess is provided in these heat transfer fins, and a heat pipe transfers heat of a heater to the recess. Is embedded so that the heat of the heater can be transferred to the display section, the printer section, and the like. As a result, the display section, the printer section, and the like can be heated, and the display section can be prevented from being unclear and the printer section can be free from printing defects.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 1 is a longitudinal sectional view of a main part of a portable information terminal and a heater housed in a heating container. FIG. 2 is a longitudinal sectional view of a main part of a portable information terminal different from FIG. FIG. 3 is an explanatory diagram of a required heat amount of the heat storage mat type and the exothermic agent type. FIG. 4 is an explanatory diagram of a heat pipe provided in a heater. FIG. 5 is an explanatory diagram of the heat transfer fins provided on the heat pipe.

A portable information terminal according to the present invention will be described with reference to FIG. Reference numeral 1 denotes a portable information terminal main body. The portable information terminal main body 1 has a battery unit 2, a display unit 3 at the front center, and a printer unit at the back of the front, respectively. Also,
Although not shown, a key input unit is provided in front of the front side. A nickel hydrogen battery is used for the battery unit 2, a dot matrix type liquid crystal is used for the display unit 3, a line thermal type is used for the printer unit, and thermal paper is used for printing paper.

The feature of the portable information terminal is that it can be operated while being moved by hand, and that the use place is not limited. However, the ambient temperature is -20 ° C. under the environmental conditions of meter reading such as water supply and electricity in winter. The temperature will be severe before and after. However, as described above, since the portable information terminal uses liquid crystal for the display unit and uses a line thermal system or thermal paper for the printer unit, the liquid crystal action of the display unit is reduced at a low temperature around -20 ° C. In some cases, the display becomes unclear, or the thermal transfer capability of the printer unit and the thermal sensitivity of the thermal paper are reduced, resulting in poor printing.

Also, at a low temperature, the output of the battery section is reduced and the life is shortened. Therefore, when the portable information terminal is used outdoors in winter, it is necessary to heat the portable information terminal to a temperature (about 0 ° C. or higher) at which the battery unit 2, the display unit 3, and the printer unit 4 function.

For example, the size of the portable information terminal is 26c in height.
m, 8.2cm wide, 3.5cm thick, the material of the heating vessel is AB
S, when the thickness δ = 1.5 mm and the outside air temperature T _o = −20 ° C., the required heat quantity Q for maintaining the portable information terminal internal temperature T _i = 0 ° C. is as follows: (1) to (4) ) Formula

[0017]

Q = S · K (T _i −T _o ) (1)

[0018]

K = 1 / (1 / α _o + δ / λ + 1 / α _i ) (2)

[0019]

Α _o = λ / L ₁ × 2 × 0.332 × Pr ^0.33 + Re ^0.5 (3)

[0020]

Re = uL / υ (4) where, S: outer surface area of the portable information terminal ‥‥ 0.0424 m ² K: heat transmission coefficient of the heating vessel ‥‥‥‥ 3.2 w / m ² k α _o : heat transfer coefficient on outer surface, α _i : heat transfer coefficient on inner surface ‥‥ 4 w / m ² k λ: heat conductivity of ABS の 0.0224 w / mk L ₁ : representative length 代表{0.082m Pr: Prandtl number} 0.722 Re: Reynolds number u: Wind speed {2m / s L: Length} {0.082m}: Viscosity coefficient {0.12 × 10 ^-4 m ² / s When these values are substituted into the above equation, it is necessary to maintain the inside at 0 ° C. The required heat quantity Q = 2.7w.

Reference numeral 5 denotes a heater, and reference numeral 6 denotes a heat pipe. The heater 5 is provided at the bottom of the portable information terminal main body 1 at the bottom of the heating vessel 7 and is made of a mixture of an oxygen supply agent and a combustible agent. An exothermic agent is used. Metal oxides such as iron oxide, copper oxide and lead oxide are used as the oxygen supply agent, and metals such as titanium and iron or silicon such as silicon or the like, which have a higher heat of oxidation than the metal forming the oxidant, are used as the combustible agent. A semimetal is used, and is composed of a mixture of one or more of the oxidizing agents and one or more of the combustibles alone or an alloy thereof.

The exothermic agent is a so-called self-combustion type exothermic agent, which generates a large heat of oxidation when the combustible agent oxidizes by removing oxygen from the oxide. Since the heat generated by the exothermic agent lasts for a long time, the exothermic agent is not frequently replaced when used outdoors for meter reading of water, electricity, etc.
It is possible to provide a simple portable information terminal without having to prepare an external power supply such as a battery. Since the exothermic agent is a self-combustion exothermic agent, it is possible to obtain a high enough temperature to operate the heat pipe 6.

In place of the above-mentioned exothermic agent, it is also possible to use an exothermic agent which generates heat by an air oxidation reaction used in a disposable body warmer or the like. Also in this case, when used outdoors for meter reading of water supply, electricity, etc., the exothermic agent is not frequently exchanged, and there is no need to prepare an external power source such as a battery, and a simple portable information terminal can be provided. It is. Here, regarding the method using the exothermic agent of the present invention and the method using the conventional heat storage mat, when the outside air temperature is −20 ° C., the amount of heat for maintaining the temperature inside the portable information terminal at 0 ° C. or more is shown. This will be described in 2.

In FIG. 3, the horizontal axis is time, and t ₁ is the time required to maintain the temperature inside the portable information terminal at 0 ° C. or higher. The vertical axis is the temperature inside the portable information terminal. Since the temperature inside the portable information terminal by the heat generation of the exothermic agent in the exothermic agent system of the present invention can always held at 0 ℃ vicinity, amount of heat required for the required time t ₁ is □ ABCD, that is, the amount of heat Q _1. Since there is no self-heating in the conventional heating mat method, it is necessary to first heat to high temperature E to maintain the temperature at 0 ° C. or higher, and it is necessary to be able to maintain 0 ° C. at the required time t _1. Becomes Therefore, the amount of heat required for the required time t ₁ is □ ABCD + △ BEC, that is, Q ₁ + Q ₂ .

As described above, the calorific value of the conventional heat storage mat type is smaller than the calorific value of the exothermic agent type of the present invention by ΔBEC, ie, Q _2.
Extra heat is required. The exothermic agent system by self-heating according to the present invention does not need to be initially heated to a high temperature as compared with the conventional exothermic mat system, so that there is no extra heat and efficient heating can be performed. The heat pipe 6 is a hermetically sealed tube in which a working fluid such as a refrigerant is sealed, and heat-connects the heater 5 as a heating source to the battery section 2, the display section 3, and the printer section 4 as heat absorbing sections. Is what you do.

That is, the refrigerant in the heat pipe 6 heated by the heater 5 becomes vapor and heats the battery unit 2, the display unit 3, and the printer unit 4. After the heating, the vapor refrigerant becomes a condensed liquid and returns to the heater 5 again. By repeating this, the battery unit 2, the display unit 3, and the printer unit 4 are heated. In this case, since the evaporation and condensation of the refrigerant in the heat pipe are performed at the same temperature, the temperature of the heating source can be reduced to about the temperature of the heat absorbing portion.

The heating container 7 comprises a portable information terminal 1, a heater 5,
The heat pipe 6 is housed therein, and is formed of a heat insulating material so that heat in the container does not leak to the outside. Reference numeral 8 denotes a lid, which is provided on the upper part of the heating container 7 and is made of a heat insulating material so as not to leak the heat in the container to the outside.

The heat of the heater 5 is transferred to the heat pipe 6
Thus, heat is transmitted to the battery unit 2, the display unit 3, and the printer unit 4 so as to be heated. As a result, even when the ambient temperature drops to about −20 ° C., the temperature of the battery unit 2, the display unit 3, and the printer unit 4 of the portable information terminal can be heated to a temperature at which each unit functions (about 0 ° C. or higher). It is like that. When the ambient temperature is not so low, as shown in FIG. 2, the heat insulation of the heating container 7 and the lid 8 is increased, and the portable information terminal 1 is used without using a heat pipe.
Can be directly heated by the heater 5.

Further, a method of effectively transferring the heat of the heat pipe to the battery unit 2, the display unit 3, and the printer unit 4 will be described with reference to FIGS.

Reference numeral 9 denotes a heat transfer fin. The heat transfer fin 9 is fixed to the heat pipe 6 and is provided for thermal contact with the back surface of the battery unit 2. Reference numeral 10 denotes a heat transfer fin. The heat transfer fin 10 is fixed to the heat pipe 6 and provided to be in thermal contact with the back surface of the display unit 3. Reference numeral 11 denotes a heat transfer fin.
Is fixed to the heat pipe 6 and provided for thermal contact with the back surface of the printer unit. Each of the heat transfer fins 9, 10, and 11 has a concave portion 12 provided at the center of the heat transfer fin, and the heat pipe 6 is embedded in the concave portion. The shape of the concave portion is formed so as to match the curvature of the heat pipe 6 to improve the heat transfer effect between the heat pipe 6 and the heat transfer fins.

Thus, heat transfer fins which are in thermal contact with one side of the battery section 2, display section 3 and printer section 4 are provided, and a concave portion 12 is provided at the center of the heat transfer fins. The heat pipe 6 can be embedded in the recess 12. Thereby, the heat of the heater 5 is transferred to the heat pipe 6.
The heat transfer fins effectively transfer heat to the battery unit 2, the display unit 3, and the printer unit 4 so that they can be heated.

[0032]

According to the portable information terminal of the present invention, a heater is provided in a heat retaining container for accommodating the portable information terminal, and the heat of this heater is directly or through a heat pipe. Since it is provided to the display unit, printer unit, etc. of the portable information terminal itself, the temperature of each unit can be heated to the functional temperature (0 ° C or higher) even when used outdoors in winter, and the liquid crystal display on the display unit It is possible to provide a portable information terminal free from defects and unclear printing on the printer section.

Further, as in claims 2, 3, 5, and 6,
Since the heater is composed of a heating agent composed of a mixture with an oxygen supply agent or a heating agent that generates heat upon contact with air, there is no need to prepare an external power supply such as a battery, and the heater is used outdoors with a meter reader or the like. Even in such a case, it is possible to provide a simple portable information terminal in which the exothermic agent is not frequently replaced.

Further, a heat transfer fin which is in thermal contact with the display section, the printer section and the like is provided, a concave portion is provided in these heat transfer fins, and a heat transfer device for transferring the heat of the heater to the concave portion. Since the pipe is embedded, the heat of the heat pipe can be effectively transferred to the display unit, the printer unit, and the like.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a portable information terminal of the present invention.

FIG. 2 is an essential part longitudinal cross sectional view of a portable information terminal different from FIG. 1;

FIG. 3 is a characteristic diagram of a required amount of heat between the heat storage mat method and the heating agent method.

FIG. 4 is a perspective view of a heat pipe of the present invention.

FIG. 5 is a cross-sectional view of the heat transfer fin of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Portable information terminal main body, 2 ... Battery part, 3 ... Display part, 4 ...
Printer section, 5: heater, 6: heat pipe, 7: heating vessel, 8: lid, 9: heat transfer fin, 12: recess.

Claims (1)

[Claims] A heating device is provided in a heating container for accommodating a portable information terminal, and heat of the heating device is transferred to a display section of a portable information terminal main body.
A portable information terminal provided to a printer unit or the like.