JPH11153970A - Light leakage prevention device - Google Patents

Abstract

(57) [Summary] [Problem] Light emitted from a light emitting LED is reflected on a case, diffusely reflected on a printed circuit board formed of a translucent material such as glass epoxy, and diffused to the periphery, and this diffuses from an adjacent display window. An object of the present invention is to prevent the display window from being illuminated and being erroneously recognized as being illuminated. SOLUTION: A light shielding rib 5 is provided on a case 3 from a position between display windows 4 to a position between light emitting LEDs 2 on a printed circuit board 1, and light is transmitted to a position of the printed circuit board 1 below the light shielding rib 5. A slit 8 is provided. As a result, even if the light emitted from one of the light emitting LEDs 2 is reflected on the case 3, it passes through the light-transmitting slit 8 as it is, so that the light is not diffused on the printed circuit board 1, and erroneous display is prevented. Can be.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light leakage preventing device for a display device having a display window for illumination in an electric device such as a telephone or a facsimile.

[0002]

2. Description of the Related Art FIG. 6 shows the structure of a conventional light leakage preventing device for a display device of this type. In FIG. 6, reference numeral 1 denotes a printed circuit board on which a plurality of light emitting LEDs 2 are mounted. Reference numeral 3 denotes a case for accommodating the printed circuit board 1, and a display window 4 is provided at a position corresponding to each light emitting LED 2.
Are formed. Case 3 also includes each light emitting LED 2
Light shielding ribs 5 are formed toward the printed circuit board 1 at positions between the respective display windows 4 formed corresponding to. The height of the light-blocking rib 5 is set so that the adjacent light-emitting LED cannot be seen from one display window 4. Reference numeral 6 denotes a transparent or translucent panel, which is adhered to the case 3 via a double-sided adhesive tape 7. When a specific light emitting LED 2 associated with the switch emits light by a user's operation of the switch, the light can be visually recognized through the display window 4 to notify the user that a specific function in the device is being performed. . Further, the light of the emitting LED 2 is blocked by the light shielding rib 5 so that the light does not leak to the display window 4 adjacent to the light emitting display window 4.

[0003]

However, in the conventional light leakage prevention device, when the light emitting intensity of the light emitting LED 2 is high, the light emitted from the light emitting LED 2 is reflected on the back surface of the case 3 and furthermore, such as glass epoxy resin. Since the light is diffusely reflected on the printed circuit board 1 formed of a translucent material and diffused to the periphery, the light may appear to be blurred from the adjacent display window. In such a situation, the adjacent light emitting LE
Misidentifying that D fired, misoperation of the device,
Sometimes the device is mistaken as having failed. Also,
There is a problem that the light from the light emitting LED leaks to the outside of the case, thereby deteriorating the appearance.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a light leakage preventing device capable of reliably preventing light leakage.

[0005]

According to the present invention, in order to achieve the above object, a light-transmitting hole is formed in a portion of a printed circuit board where light from a light emitting LED is reflected by a case and diffusely reflected and diffused by the printed circuit board. It is provided to prevent light diffusion. This makes it possible to reliably prevent light leakage with a simple configuration.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is characterized in that a light-transmitting hole for preventing reflection of light from a light-emitting element is provided on a printed circuit board on which the light-emitting element is mounted. And has an operation of reliably preventing light leakage with a simple configuration.

According to a second aspect of the present invention, a printed circuit board on which a light emitting element is mounted is housed in a case, and a display window for the light emitting element is provided in a case portion above the light emitting element. In a display device in which light of the light emitting element is visible from the outside of the case through, a light shielding rib is provided in the case from a position next to the display window to a position next to the light emitting element on the printed circuit board, A light leakage prevention device characterized by providing a light-transmitting slit at the position of the printed board below the light-shielding ribs, even when a single light-emitting element is mounted on the printed board.
It has the function of preventing light from the light emitting element from being reflected by the printed circuit board and reliably preventing light leakage.

According to a third aspect of the present invention, a printed circuit board on which a plurality of light emitting elements are mounted is housed in a case,
In a display device in which display windows for light emitting elements are respectively provided in upper case portions of the plurality of light emitting elements so that light of the respective light emitting elements can be seen from outside the case through the respective display windows, each display window is provided in the case. A light-shielding rib is provided from a position between the light-emitting elements to a position between the light-emitting elements of the printed board, and a light-transmitting slit is provided at a position of the printed board below the light-shielding rib. The leak prevention device has a function of preventing light from a light emitting element from being reflected by the printed circuit board and reliably preventing light leakage even when a plurality of light emitting elements are mounted on the printed board.

According to a fourth aspect of the present invention, in the display window for a light emitting element, an outer edge of the display window opposite to the light shielding rib and a lower end of the light shielding rib on the display window side. 4. The light-transmitting slit according to claim 2, wherein the light-transmitting slit is provided such that an edge of the light-transmitting slit opposite to the display window is located outside a straight line passing through the end of the light-transmitting slit. The light leakage preventing device has a function of preventing light from a light emitting element from being reflected by a printed circuit board in a relatively wide range, thereby reliably preventing light leakage.

The invention according to claim 5 of the present invention is characterized in that the width of the light-transmitting slit is formed larger than the thickness of the corresponding light-blocking rib. This has the effect of preventing light from the light emitting element from being reflected by the printed circuit board in a relatively wide range, thereby reliably preventing light leakage.

According to a sixth aspect of the present invention, the light leakage rib according to the second aspect is characterized in that the light shielding rib is provided so that its lower end penetrates into the corresponding light transmitting slit. This is a prevention device, which has a function of reliably blocking light from a light emitting element and preventing light leakage.

According to a seventh aspect of the present invention, there is provided a light leakage device according to the third aspect, wherein the light shielding rib is provided so that a lower end portion thereof penetrates into the corresponding light transmitting slit. This is a prevention device, which has a function of reliably blocking light from a light emitting element and preventing light leakage.

According to an eighth aspect of the present invention, the light-shielding rib has a height at which a lower end portion is in contact with the surface of the printed circuit board, and a length in a longitudinal direction of the light-transmitting slit. 3. The light leakage preventing device according to claim 2, wherein the lower end of the light-shielding rib is formed on the surface of the printed circuit board even when a single light emitting element is mounted on the printed circuit board. , The light from the light emitting element can be reliably shut off, and even when the device is vibrated by a bell in a telephone or the like, it has an effect of preventing generation of chatter between the case and the printed circuit board.

According to a ninth aspect of the present invention, the light-shielding rib has a height at which a lower end portion is in contact with the surface of the printed circuit board, and a length in a longitudinal direction of the rib is adjusted in a longitudinal direction of the corresponding light-transmitting slit. 6. The light leakage prevention device according to claim 3, wherein the light leakage prevention device is formed to be longer than the length of the light leakage prevention device even when a plurality of light emitting elements are mounted on a printed circuit board. Since the lower ends of the ribs are in contact with the surface of the printed circuit board, light from the light emitting elements can be reliably shut off, and even when the device is vibrated by a bell in a telephone or the like, the gap between the light shielding rib and the printed circuit board is reduced It has the function of preventing chattering noise.

According to a tenth aspect of the present invention, in the first aspect of the present invention, a light-shielding wall is raised near the light-shielding rib from the printed circuit board side. The light leakage prevention device according to any one of 1 to 9, which has a function of reliably blocking light from a light emitting element and preventing light leakage.

(Embodiment 1) FIG. 1 shows a configuration of a light leakage preventing device according to a first embodiment of the present invention. For convenience of explanation, reference numerals used in the description of the conventional example of FIG. Used for similar components. In FIG. 1, 1
Is a printed circuit board formed of a translucent material such as a glass epoxy resin, and has a plurality of light emitting LEDs 2 on its surface.
Has been implemented. Another light emitting element may be used instead of the light emitting LED 2. Reference numeral 3 denotes a case for housing the printed circuit board 1, and a display window 4 is formed at a position corresponding to each light emitting LED 2. The case 3 is also provided with a light shielding rib 5 at a position between the plurality of display windows 4 formed corresponding to the plurality of LEDs 2 toward the printed circuit board 1. The thickness of the light shielding rib 5 is substantially the same as the thickness of the case 3,
It is formed in a rectangular shape having a certain length in the depth direction of the drawing, and its height is set so that one of the display windows 4 cannot see the other adjacent light emitting LED 2. Reference numeral 6 denotes a transparent or translucent panel, which is adhered to the case 3 via a double-sided adhesive tape 7. Reference numeral 8 denotes a light-transmitting slit provided at a position on the printed circuit board 1 corresponding to the lower end of the light-shielding rib 5, having a width similar to the thickness of the light-shielding rib 5 and a rectangle having the same length as the light-shielding rib 5. It is formed in a shape.

In FIG. 1, when a specific light-emitting LED 2 associated with the switch emits light by a user's operation of the switch, the light is visually recognized through a display window 4 to indicate that a specific function of the device is being executed. Notify user. Most of the light emitted from the LED 2 is blocked by the light-blocking ribs 5 so that light does not leak to the display window 4 adjacent to the light-emitting display window 4. Part of the light from the LED 2 is reflected by the case 3 and travels to the printed circuit board 1. Since the light transmitted through the light transmitting slit 8 is formed at the destination, the light is diffused on the printed circuit board 1 by the light transmitting slit 8. Is prevented. Therefore, the adjacent display window 4 does not look dim.

As described above, according to the first embodiment, the light shielding rib 5 is provided on the case 3 from the position between the display windows 4 to the position between the light emitting LEDs 2 on the printed circuit board 1. Since the light-transmitting slit 8 is provided at the position of the printed circuit board 1 below the light emitting element 5, the light emitted from one of the light emitting LEDs 2 is not diffused on the printed circuit board 1 and is not seen from the other display window 4, so that light leakage is prevented. It is possible to surely prevent such a situation and eliminate erroneous recognition of the display.

(Embodiment 2) FIG. 2 shows a configuration of a light leakage preventing device according to a second embodiment of the present invention. This embodiment is different from the first embodiment shown in FIG. 1 in that the width of the light transmitting slit 8A is larger than the thickness of the light shielding rib 5. That is, the light-transmitting slit 8A is formed outside a straight line passing through the outer edge 4a of the one display window 4B opposite to the light-shielding rib 5 and the end 5a of the lower end of the light-shielding rib 5 on the display window 4B side. The light transmitting slit 8 is provided so that the edge 8a on the opposite side to the display window 4B is located. This relationship is the same in the relationship between the other display window 4A, the light shielding rib 5, and the light transmitting slit 8A.

As described above, according to the second embodiment, the width of the light-transmitting slit 8A is made larger than the thickness of the light-shielding rib 5, so that the edge of the light-transmitting slit 8A is viewed from the adjacent display window 4B. The portion 8a is hidden by the light shielding rib 5 and cannot be seen, and only the light transmitting slit 8A can be seen. In other words, a light emitting LED
Most of the light emitted from 2A and reflected by case 3 passes through light-transmitting slit 8A, so that diffusion on printed circuit board 1 can be prevented in a relatively wide range, and light leakage is reliably prevented. As a result, erroneous recognition of the display can be eliminated.

(Embodiment 3) FIG. 3 shows a configuration of a light leakage preventing device according to a third embodiment of the present invention. This embodiment is different from the second embodiment shown in FIG. 2 in that the light shielding rib 5A penetrates into the light transmitting slit 8A. That is, the height of the light-shielding rib 5A is larger than the distance between the case 3 and the printed circuit board 1. The lower end of the light shielding rib 5A is
It may penetrate through the light transmitting slit 8A.

As described above, according to the third embodiment, since the lower end of the light-shielding rib 5A penetrates into the light-transmitting slit 8A, almost all the light from the light-emitting LED 2 is blocked.
A can block the light, reliably prevent light leakage,
It is possible to eliminate erroneous recognition of the display.

(Embodiment 4) FIG. 4 shows a configuration of a light leakage preventing device according to a fourth embodiment of the present invention. The present embodiment is different from the above-described first and second embodiments in that the light-shielding rib 5B has a height at which the lower end thereof is in contact with the surface of the printed circuit board 1 and the length in the longitudinal direction of the light-transmitting slit 8 Is formed longer than the length in the longitudinal direction. As a result, both ends of the lower end of the light shielding rib 5B come into contact with the printed circuit board 1.

As described above, according to the fourth embodiment, since the light-shielding rib 5B is formed at a height such that the lower end portion is in contact with the surface of the printed circuit board 1, light from the light emitting LED 2 can be almost blocked. . When the lower end of the light shielding rib B5 and the surface of the printed circuit board 1 are brought close to each other with a gap,
When the bell rings on a telephone or the like, the printed circuit board 1 vibrates together with the case 3, and there is a possibility that chatter sound is generated between the light-shielding rib 5 </ b> B and the printed circuit board 1. On the other hand, in the present embodiment, both ends of the lower end of the light-shielding rib 5B are in contact with the surface of the printed circuit board 1, so that even if vibration occurs due to a bell in a telephone or the like, the light-shielding rib 5 and the printed circuit board 1 are not affected. The occurrence of chattering sound can be prevented.

(Embodiment 5) FIG. 5 shows a configuration of a light leakage preventing device according to a fifth embodiment of the present invention. The present embodiment is different from the above embodiments in that a light shielding wall 9 is raised near the light shielding rib 5 from the printed circuit board 1 side. That is, a light-shielding wall 9 having a triangular cross section is provided at a position on one side of the light-transmitting slit 8 of the printed circuit board 1.
Is fixed by bonding or the like. This light shielding wall 9
It may be provided on either side of the light shielding rib 5, but may be provided on both sides.

As described above, according to the fifth embodiment, the light-shielding wall 9 is raised from the printed circuit board 1 near the light-shielding rib 5, so that the light from the light emitting LED 2 can be almost completely blocked by the light-shielding rib 5. Can prevent light leakage,
It is possible to eliminate erroneous recognition of the display.

In each of the above embodiments, the light emitting LED
And two display windows, but the same applies to a case where there are two or more display windows. In addition, in the case of two, when the wall of the case is used as the light shielding member on both sides, only one light shielding rib is required, and when all the light is shielded by the light shielding rib, three light shielding ribs are required. In the case of a single light-emitting LED and a single display window, no light-shielding rib is required if all cases are to be shielded from light, and if one case is to be shielded from light, one light-shielding rib is required. Are required.

[0028]

According to the present invention, as is apparent from the above embodiment, light reflected by a case from a light emitting element such as a light emitting LED is irregularly reflected on a printed board formed of a translucent material such as glass epoxy resin. Since light diffusion holes are provided in that part of the printed circuit board to prevent diffusion to the surroundings, light leakage can be reliably prevented,
The operator does not mistakenly operate the device or misunderstand that the device has failed due to misrecognition of the display. In addition, it is possible to prevent the appearance from being deteriorated due to the light leaking out of the case.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional front view showing a configuration of a light leakage prevention device according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged cross-sectional front view showing a configuration of a light leakage prevention device according to a second embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional front view showing a configuration of a light leakage prevention device according to Embodiment 3 of the present invention.

FIG. 4 is an enlarged sectional side view showing a configuration of a light leakage prevention device according to Embodiment 4 of the present invention.

FIG. 5 is an enlarged sectional front view showing a configuration of a light leakage prevention device according to a fifth embodiment of the present invention.

FIG. 6 is an enlarged cross-sectional front view showing a configuration of a light leakage prevention device in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed circuit board 2, 2A, 2B Light emitting LED 3 Case 4, 4A, 4B Display window 5, 5A, 5B Light-shielding rib 6 Panel 7 Double-sided adhesive tape 8, 8A Light-transmitting slit 9 Light-shielding wall

Claims (10)

[Claims] 1. A printed circuit board on which a light emitting element is mounted,
A light leakage prevention device provided with a light transmitting hole for preventing reflection of light from a light emitting element. 2. A printed circuit board on which a light emitting element is mounted is accommodated in a case, a display window for the light emitting element is provided in a case portion above the light emitting element, and light of the light emitting element can be seen from outside the case through the display window. In the display device, a light-shielding rib is provided on the case from a position next to the display window to a position next to the light-emitting element on the printed board, and a position of the printed board below the light-shielding rib is provided. A light leakage prevention device, characterized in that a light-transmitting slit is provided in the device. 3. A printed circuit board on which a plurality of light-emitting elements are mounted is housed in a case, display windows for the light-emitting elements are respectively provided in upper case portions of the plurality of light-emitting elements, and the display windows are provided from outside the case through the respective display windows. In a display device in which light of each light emitting element is made visible, a light shielding rib is provided in the case from a position between each display window to a position between each light emitting element on the printed board, and the light shielding rib is provided. A light leakage prevention device, wherein a light-transmitting slit is provided at a position of a printed board below a rib. 4. An edge portion of a display window for a light emitting element, which is outside a straight line passing through an outer edge portion opposite to a light-shielding rib and an end portion of a lower end portion of the light-shielding rib on the display window side. 4. The light leakage prevention device according to claim 2, wherein the light-transmitting slit is provided such that an edge of the light-transmitting slit on a side opposite to the display window side is located. 5. The light leakage prevention device according to claim 2, wherein the width of the light-transmitting slit is formed larger than the thickness of the corresponding light-blocking rib. 6. The light leakage prevention device according to claim 2, wherein the light shielding rib is provided such that a lower end portion of the rib penetrates into the corresponding light transmitting slit. 7. The light leakage prevention device according to claim 3, wherein the light shielding rib is provided such that a lower end portion of the rib penetrates into the corresponding light transmitting slit. 8. The light-shielding rib is formed such that its lower end has a height in contact with the surface of the printed circuit board and its longitudinal length is longer than the longitudinal length of the light-transmitting slit. The light leakage prevention device according to claim 2. 9. The light-shielding rib is formed such that its lower end has a height in contact with the surface of the printed circuit board and its longitudinal length is longer than the corresponding longitudinal length of the light-transmitting slit. The light leakage prevention device according to claim 3, 4, or 5. 10. A light-shielding wall rising from a printed circuit board side in the vicinity of a light-shielding rib.
The light leakage prevention device according to any one of the above.