JPH0527995U - Sealed housing structure for EL light emitting device - Google Patents

Abstract

(57) [Abstract] [Purpose] To make the EL light emitting element less susceptible to temperature and humidity. [Structure] An EL light emitting element 1 is arranged in a storage space formed by a case 4 and a printed circuit board 2. At least an electronic component 8 is mounted on the outer surface of the printed board 2.
At least a communication part, such as a space between the outer periphery of the printed circuit board 2 and the case 4, where the storage space of the EL display element 1 and the outside air communicate with each other is sealed with a completely-curing primary sealing material 6. Even if the entire outer surface of the printed circuit board 2 is hardened, it is soft.
Secondary sealing is performed with the next sealing material 7.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a sealed housing structure for an EL light emitting element, and more particularly to a sealed housing structure for an EL light emitting element of an apparatus used in a place exposed to high temperature and high humidity.

[0002]

[Prior Art]

 An EL (electroluminescence) light emitting element is a solid-state light emitting element which is made of a phosphor material and emits light when a high electric field is applied. Since this EL light emitting element has low power consumption and low heat generation characteristics and can be formed into a thin and free shape, in recent years, it has been widely used for OA equipment, FA, HA equipment and the like.

[0003]

[Problems to be solved by the device]

 However, the EL light emitting element has very poor resistance to temperature and humidity, and a blackening phenomenon occurs from the peripheral portion to the central portion in about 200 hours at a temperature of 20 ° C. and a humidity of 90%, resulting in a luminance Result in a decrease. Therefore, it was a problem when it was installed in a device that is used in places with high temperature and high humidity, such as outdoors.

The present invention has been made in view of the above points, and an object of the present invention is to provide a sealed housing structure for an EL light emitting element that is not easily affected by temperature and humidity. ..

[0005]

[Means for Solving the Problems]

 According to the present invention, in order to achieve the above object, at least a communication part, such as a space between an outer periphery of a printed circuit board and a case, in which the storage area of the EL display element communicates with the outside air is primary-sealed with a completely curable resin, Even if the entire outer surface of the printed circuit board is cured, it is secondarily sealed with a soft resin.

[0006]

According to the present invention, the EL light emitting device is arranged in the storage space formed by the case and the printed circuit board, and the electronic components are mounted on the outer surface of the printed circuit board by the above-mentioned configuration. In this device, the printed circuit board and the case are completely sealed so that they are not easily affected by temperature and humidity even when used in places with high temperature and humidity such as outdoors.

[0007]

【Example】

 FIG. 1 shows an embodiment of the present invention. This embodiment shows a case where the present invention is applied to a device provided with a numeric keypad. Such a device is provided with a display unit for displaying a numerical value input with a ten-key pad, the display unit is configured by using the liquid crystal display element 3, and the EL light emitting element 1 is used as simple illumination of the liquid crystal display element 3. is there.

FIG. 1 shows a cross section of a display portion of such a device. In this display portion, a printed board 2 having an EL light emitting element 1 mounted on the front surface is provided on the rear surface of an opening of a box-shaped case 4. The EL light-emitting element 1 illuminates the liquid crystal display element 3 attached to the display window 4a formed on the front surface of the case 4 from the rear side by screwing. That is, the EL light emitting element 1 is used as a so-called backlight. The case 1 also closes the direction in which the liquid crystal display element 3 and the EL light emitting element 1 are accommodated, which is orthogonal to the plane of FIG. The liquid crystal display element 3 is also attached to the printed board 2.

By the way, in the conventional display unit of this type, a gap is formed between the liquid crystal display element 3 and the case 4, or between the printed circuit board 1 and the case 4, and ventilation is performed through this gap. The housing portion of the EL light emitting element 1, that is, the space surrounded by the case 4, the printed circuit board 2, and the liquid crystal display element 3 is in a high temperature and high humidity state. In this case, as described above, the blackening phenomenon occurs in the EL light emitting element 1 having poor temperature and humidity resistance.

Therefore, in this embodiment, a rubber seal sheet 5 is sandwiched between the case 4 and the liquid crystal display element 3, and a gap such as a joint portion between the printed circuit board 2 and the case 4 is sealed. I am doing it. By the way, regarding the seal between the printed circuit board 2 and the case 4, first, there is a gap between the outer periphery of the printed circuit board 2 and the case 4, a through hole hole (not shown), and the like. The communicating portion that communicates is primarily sealed with a primary sealing material 6 such as a curable epoxy resin. Then, after the primary sealing material 6 is cured, the entire mounting surface side of the electronic component 8 of the printed circuit board 2 is completely sealed by using the secondary sealing material 7 which is a soft resin such as urethane resin even when cured.

The secondary sealing is performed after the primary sealing as described above for the following reason. That is, it is not preferable to seal the portion on which the electronic component 8 is mounted because it is completely cured with the above-mentioned curable epoxy resin or the like. Therefore, it is conceivable to use a relatively soft resin, but in this case the resin flowability is good and it enters the space containing the liquid crystal display element 3 formed by the printed circuit board 2 and the case 4. The display surface of the liquid crystal display element 3 may be soiled. For this reason, in the present embodiment, after the primary sealing is performed using the completely curable resin, the secondary sealing is performed using the soft resin even if it is cured.

With this configuration, the EL light emitting element 1 can be completely enclosed and housed. When the blackening phenomenon of the liquid crystal display element 3 is measured by the device thus formed, the result is that the blackening phenomenon does not occur unless it is 700 hours or more under the condition of 20 ° C. and 90%. It was If this device is used for 30 minutes a day, for example, with a usage time of 1 minute each time, and if the temperature at 20 ° C and 90% or more is halved a year, blackening will occur for 7.7 years. There will be no.

[0013]

[Effect of the device]

 As described above, according to the present invention, at least a communication portion, such as a space between the outer periphery of the printed circuit board and the case, which communicates between the housing of the EL display element and the outside air is primary-sealed with a completely curable resin. Even if the entire outer surface of the device is cured, it is secondarily sealed with a soft resin, so the EL light emitting element is placed in the storage space formed by the case and the printed circuit board, and at least electronic components are mounted on the outer surface of the printed circuit board. In this device, the printed circuit board and the case can be completely sealed, making it less susceptible to the effects of temperature and humidity even when used in places with high temperature and high humidity such as outdoors.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention.

[Explanation of symbols]

 1 EL Light Emitting Element 2 Printed Circuit Board 4 Case 6 Primary Sealing Material 7 Secondary Sealing Material 8 Electronic Parts

Claims (1)

[Scope of utility model registration request] 1. An apparatus in which an EL light emitting element is arranged in a storage space formed by a case and a printed circuit board, and at least an electronic component is mounted on an outer surface of the printed circuit board, between an outer periphery of the printed circuit board and the case. At least a communication part for communicating the storage part of the EL display element with the outside air,
A sealed housing structure for an EL light-emitting element, characterized in that a primary seal is made with a completely curable resin, and a secondary seal is made with a soft resin even if the entire outer surface of the printed circuit board is cured.