JPS6313584A - Dewing preventing device for image display - Google Patents

Abstract

PURPOSE:To attain the use of a device even in a bad atmosphere such as a high temperature and high humidity by rising a temperature in a closed box a little higher than outer air temperature and preventing the dewing to a transparent plate or a CRT tube surface by the heating of an image display device or a heating wire. CONSTITUTION:In the upper direction of especially a heating part such as a power source 1c, the endothermic part of a heat pipe 5, which is a heat releasing member, is arranged. A convection heat from the power source 1c and a diffusion heat by a microfan 4 are collected by the endothermic fin 5a of the heat pipe 5, naturally heat-released by the heat releasing fin 5b of the external part and the temperature in a closed box baffle 3 is always higher than the outer air and stable. Thus, by the natural convection, the conductive heat of the closed box and the heat diffusion of a microfan 4, a glass plate 2 of the front surface of CRT always comes to be the temperature higher than the outer air by several degrees (about 2-3 deg.C), and the dewing (cloud) can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dew condensation-preventing image display device that can be used in a high temperature and humid environment such as a bathroom.

[Conventional technology]

Conventional image display devices using CRTs (cathode ray tubes), such as television receivers, do not have a sealed structure, and internal heat generation is cooled by providing air circulation holes to naturally exchange inside and outside air, or by using fans. This forced outside air to be taken in and the hot air inside to be released to the outside.

[Problem that the invention seeks to solve]

However, the conventional image display device described above has a problem in that it cannot be used in hot and humid places such as bathrooms.

First, CRTs are made of glass and have a vacuum inside, so they have poor thermal conductivity, and since the temperature rarely rises, condensation occurs, making the displayed image invisible. Second, humid outside air enters the interior of the image display device, resulting in dew condensation when not in use, and the high humidity can corrode parts and other components, making them more likely to malfunction.

The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide an image display device that can be used even when surrounded by evil spirits, such as in hot and humid places.

[Means for solving problems]

Means for achieving the above object in the present invention includes a sealed box having a colorless or colored transparent plate on the front surface, and a sealed box that is housed in the sealed box and that allows the transparent plate to be visually recognized at 1ffiL and generates convection heat or/or and an image display device that warms the transparent plate by conductive heat of the sealed box, and the structure utilizes the heat generated by the image display device, and communicates between the inside and outside of the sealed box to direct the heat generated by the image display device to the outside of the sealed box. A thermostat comprising a heat radiating member that radiates heat by making the temperature inside the box higher than the outside of the box, or the side that absorbs heat due to an electric current is placed inside the sealed box, and the side that generates heat due to the current is placed outside the sealed box. an element and a temperature difference detection means for detecting a temperature difference between the inside and outside of the sealed box and controlling the current so that the temperature inside the box is higher than that outside the box, or the sealed box. an image display device that is hermetically housed inside and allows the CRT tube surface to be viewed directly or through a colorless or colored transparent plate; a heating wire provided on the transparent plate or the CR'I'' tube surface; and a current in the heating wire. and temperature difference detection means for controlling the surface temperature of the transparent plate or the CRT tube surface to be higher than the outside air.

[Effect]

The present invention prevents dew condensation on the transparent plate or CRT tube surface by raising the temperature of the transparent plate or CRT tube surface slightly higher than the outside air temperature using heat generation or heating wires of the image display device. Since the sealed box completely isolates the image display device from the outside air, the outside air does not have any adverse effect on the image display device.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is an internal layout diagram of an embodiment of the present invention seen from the side, and FIG. 2 is a perspective view of the embodiment of FIG. 1. In this embodiment, a sealed box 3 with a completely waterproof and moisture-proof structure has a glass plate 2 on the front and includes a CRTla constituting an image display device 1, a printed circuit board (hereinafter referred to as PC board) 1b for display control, a power supply 10, etc. It is stored inside.

The glass plate 2 is an example of a transparent plate of the present invention, and allows the CRT display to be viewed. There are heat-generating components such as transformers, resistors, and power transistors on the power supply 1c and PC board 11, and the micro fan 4 is used to circulate and diffuse the generated convection heat, but it can be omitted if convection is performed well. You can also. At this time, the micro fan 4 circulates convection heat to warm the glass plate 2.
Preferably, it is placed in the upper front, such as in the case of The heat absorbing portion of the heat pipe 5, which is the heat dissipating member of the present invention, is arranged above the power source 10 and other parts that generate heat.

The heat pipe 5 communicates with the inside and outside of the sealed box 3, and the area around the through hole of the sealed box 3 is hermetically sealed with an adhesive (silicon rubber) or the like. Convection heat from power supply IC and micro fan 4
The diffusion force caused by this is collected by the heat absorption fins 5a fixed to the portion of the heat pipe 5 inside the sealed box 3, and vaporizes the liquid fluorocarbon gas and the like inside the heat pipe 5. On the other hand, heat pipe 5
A radiation fin 5b is fixed to the outside of the sealed box 3, and heat is naturally radiated, and the vaporized fluorocarbon gas is liquefied again. As described in -1- above, the heat generated within the sealed box 3 is radiated to the outside, but since the heat pipe 5 naturally radiates heat, the temperature inside the sealed box 3 is always higher and stable than the outside air. The capacity of the heat pipe is selected so that the temperature is 5 to 10°C. Note that the position of the heat pipe 5 may be on the back side, and is not particularly limited. In addition, heat pipes are not limited to the pipe shape shown in the figure, but also net shapes,
It may be formed into a comb shape, that is, a flat plate shape.

With the above configuration, due to natural convection, conduction heat from the sealed box, and heat diffusion from the micro fan 4, the glass plate 2 in front of the CRT always maintains the temperature distribution graph inside and outside the sealed box shown in FIG. The temperature will be several degrees (about 2 to 3 degrees Celsius) higher than the outside air.

Humidity (which causes cloudiness on the surface of the glass plate 2, that is, dew condensation)
kg・water vapor/kg・dry air) decreases by about 5% for every 1°C temperature rise. Therefore, even in an environment with 100% humidity and condensation, by simply increasing the temperature of the glass plate 2 by 1 to 2 degrees Celsius, the surface humidity of the glass plate 2 can be brought to 90 to 95%, preventing dew condensation (fogging). can do.

The third FAI uses a heat radiating plate 6 as a heat radiating member. The heat sink 6 includes a heat generating component mounting plate 6a inside the sealed box 3, and a heat sink fin 6b that communicates with this and is arranged outside the sealed box 3.
The area around the through hole of the sealed box for communicating the inside and outside of the heat sink is airtightly sealed with an adhesive (silicon rubber) or the like. The mounting position of the heat sink may be on the side or the like, and is not particularly limited. As the material for the heat sink, a material with good thermal conductivity such as aluminum is suitable. The rest of the structure is similar to the embodiment shown in FIGS. 1 and 2. Heat generating parts mounting plate 6
The heat generated at a is transferred to the radiation fins 6b by thermal conduction, and is naturally cooled by the outside air. In this case as well, because of natural cooling, the temperature inside the sealed box 3 is stable and higher than the outside air, and the heat dissipation design is designed to be 5 to 10° C. higher than the outside air. As described above, as with the use of a heat pipe, the temperature of the two surfaces of the glass plate can be increased by at least about 2 to 3 degrees Celsius, and dew condensation can be prevented.

FIG. 4 shows an embodiment in which a thermoelement 7 such as a Peltier element is used as a heat radiating structure instead of the heat radiating member of the previous embodiment. The thermoelement 7 is an n-type semiconductor 7a,!
= P-type semiconductors 7b are alternately connected to the heat-absorbing side metal 7C in the sealed box 3.
and the heat-generating side metal 7d outside the sealed box 3, and heat absorption inside the sealed box 3 is carried out by passing a current. In the above case, if the current continues to flow, it is possible to cool the air to a temperature lower than that of the outside air. Therefore, in this embodiment, a temperature difference detection means 8 between the inside and outside of the sealed box 3 as shown in FIG. The above-mentioned current is controlled so that the temperature of the two surfaces of the glass plate is about 2 to 3 degrees Celsius higher than the outside air. As an example of a configuration for this purpose, the temperature difference detection means 8 includes a first temperature sensor 8a disposed near the bottom of the glass plate 2.
A second temperature sensor 8b is provided to measure the outside air temperature.

This input signal is amplified by amplifiers 9a and 9b, level-adjusted, and inputted to a differential amplifier 10 to produce a temperature difference signal. This temperature difference signal is input to the following comparator 11, and the reference temperature difference voltage (
For example, if the temperature difference signal is compared to the equivalent of 5 to 10 degrees Celsius (iff), it will be a positive output, turn on the transistor 12 and cool the thermoelement 7 by flowing nitrogen, but if it is small, it will be a zero output or a negative output. and transistor 1
2 is cut off to turn off the current to the thermoelement 7 and stop cooling. Although the current is used as an on/off control port in the above example, it is of course possible to control the current in an analog manner. As a result of the above, the inside of the sealed box 3 can be heated 5 to 10 degrees Celsius higher than the outside air, and condensation can be prevented as described above.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be applied and implemented in various ways according to the spirit of the present invention, such as a combination of two or more of the above-mentioned different embodiments. . In addition to being used in bathrooms, it is also suitable for use in dusty environments such as factories, environments with rapid temperature changes such as constant temperature chambers, and outdoor use. In addition to television receivers, it is also used in IT
V.

It can be applied to computer terminal 2 displays, etc. Furthermore, instead of heating the glass plate using internal heat generation, the glass plate or CRT display surface is controlled to a high temperature of 2 to 3 degrees Celsius by electric heating using a glass plate with a heating wire or a CRT with a heating wire and a temperature difference detection means. It is also possible to prevent dew condensation. In this case, the heating wire is preferably provided in a non-inductive manner so as not to affect the scanning electron beam of the CRT.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide an image display device that can be used even under adverse environments such as high temperature and humidity environments and dusty environments.

[Brief explanation of the drawing]

FIG. 1 is an internal layout diagram seen from the side of an embodiment of the present invention using a heat pipe, FIG. 2 is a perspective view of the embodiment of FIG. 1,
FIG. 3 is a perspective view of an embodiment of the present invention using a heat sink;
The figure is an internal layout diagram of an embodiment of the present invention using a thermoelement seen from the side, FIG. 5 is an example of the circuit configuration of the temperature difference detection means, and FIG. 6 is a temperature distribution graph inside and outside the sealed box. 1... Image display device 2... Glass plate 3...
Sealed box 4...Microphone 5...Heat pipe 6...Radiation plate 7...Thermo element Patent applicant: Inttsuku Co., Ltd. Figure 6￥j! ON

Claims (5)

[Claims] (1) An airtight box having a colorless or colored transparent plate on the front surface, and a box that is housed in the airtight box, is visible through the transparent plate, and is heated by the convection heat of the generated heat and/or the conductive heat of the airtight box. A dew condensation prevention image comprising: a heating image display device; and a heat radiating member that communicates with the inside and outside of the sealed box and radiates heat generated by the image display device to the outside of the sealed box by raising the temperature inside the box higher than the outside of the box. Display device. (2) The dew condensation prevention image display device according to claim 1, wherein the heat radiation member is a heat pipe. (3) The dew condensation prevention according to claim 1, wherein the heat radiating member is a heat radiating plate in which part or all of the heat generating part is attached to a portion inside the sealed box so as to radiate heat. Image display device. (4) an airtight box having a colorless or colored transparent plate on the front; and a box that is housed in the airtight box, is visible through the transparent plate, and is heated by convective heat generated by heat generation and/or conducted heat of the airtight box. a heating image display device; a thermoelement having a side that absorbs heat due to an electric current placed inside the sealed box and a side that generates heat due to the current placed outside the sealed box; a thermoelement that detects a temperature difference inside and outside the sealed box; 1. A dew condensation prevention image display device, comprising: temperature difference detection means for controlling the current to a temperature difference where the inside temperature is higher than the outside temperature. (5) an image display device that is hermetically housed in an airtight box and allows the CRT tube surface to be viewed through a colorless or colored transparent plate or directly; a heating wire provided on the transparent plate or the CRT tube surface; and the heating wire. controlling the current of the transparent plate or the CRT
1. A dew condensation prevention image display device comprising: temperature difference detection means for making the surface temperature of the tube surface higher than the outside air.