JP3186283B2 - Light-emitting display unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-emitting display unit used for displaying dot patterns of characters and numerals.

[0002]

2. Description of the Related Art As this kind of light emitting display unit, an LED dot matrix display unit using an LED as a light emitting element is frequently used. In this method, a large number of LEDs are arrayed and mounted on a substrate in a matrix, and a dot pattern is displayed by selectively lighting the LEDs. The housing is usually superimposed on the substrate. Then, a larger number of these units are arranged to form a display screen.

As shown in FIG. 1, a housing used for an LED dot matrix display unit is a rectangular plate-shaped resin body corresponding to a substrate, and a large number of apertures 11 are provided at positions on the substrate corresponding to the LEDs. , And a projection 14 is provided on the rear surface to be attached to the substrate. The opening 11 penetrates the front and back of the housing, and fits the LED on the board.

[0004] One of the purposes of the aperture 11 is to reflect light emitted from the LED on the inner peripheral surface of the aperture 11 to increase the reflection efficiency. For this reason, the resin forming the housing has a bright color such as white or milky white. Further, in order to prevent a decrease in contrast due to the bright color of the housing, the entire surface of the housing, that is, adjacent openings 11, 1 are provided.
The entire surface of the so-called bank portion sandwiched between the two is coated with dark color such as black or gray. As a coating method, solid coating by inexpensive screen printing is usually used.

[0005]

However, in solid coating by screen printing, dripping and swelling of ink cannot be avoided. The ink dripping is a phenomenon in which a part of the ink 15 applied to the surface of the housing flows into the opening 11 to form a projection as shown in FIG. B) is a phenomenon in which the ink 15 swells at the peripheral edge of the opening 11.

[0006] Ink dripping was not a particular problem before. However, in recent small units this is LE
D became uneven in luminance.

[0007] That is, in the LED used in the LED dot matrix display unit, as is well known, a certain degree of luminance unevenness cannot be avoided. Conventional LED dot matrix display units are relatively large, such as 94 mm square and 64 mm square. In such a large unit, the hole diameter and the pitch of the holes are as large as several millimeters, and even if there is ink dripping in the holes, it does not promote unevenness in brightness of the LED. However, in recent small units such as 32 mm square, the hole diameter and pitch are as small as 1 to 2 mm, and ink dripping in the opening promotes uneven brightness of the LED,
The display quality is impaired.

It is generally said that the uneven brightness of the LED can be improved by increasing the color of the ink applied to the surface of the housing, but such a reduction in contrast is caused.

On the other hand, the swelling of the ink prevents the sheet from uniformly adhering to the surface of the housing when a sheet such as a diffusion sheet is attached to the surface of the housing. As a result, the sheet partially rises from the surface of the housing, and the dark paint appears thin at that portion, resulting in a decrease in contrast.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light emitting display unit capable of improving luminance unevenness without lowering contrast even when a housing is small.

[0011]

A light-emitting display unit according to the present invention has a plurality of light-emitting elements regularly arranged on a substrate and a plurality of apertures into which the respective light-emitting elements are fitted. In a light-emitting display unit that superimposes a housing on the substrate and selectively illuminates each light-emitting element on the substrate to display a dot pattern, the housing has a bright color having a high reflection efficiency with respect to light emitted from the light-emitting element. No, and, on the surface except the periphery of each aperture of the housing, subjected to dark paint for contrast improvement, Hirakianashu
The width of the unpainted part where the dark paint of the enclosure is not applied is 0.05 to
It is characterized by 0.3 mm .

[0012]

[ Function ] A dark color is applied except for the area around each hole ,
The unpainted area where the dark paint is not applied is 0.05mm in width.
〜0.3 mm. When the paint runs off, the run-off is absorbed in the unpainted portion, so that the ink does not drool into the opening. In addition, the swelling of the ink at the peripheral edge of the opening is eliminated.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a front view of a housing showing one embodiment of the present invention.

The housing 10 is a square plate made of a light-colored resin such as white or milky white and has a size of, for example, 32 mm square, with one side being 1.3 in the vertical and horizontal directions.
The openings 11 have a square shape of mm and are provided at a pitch of 2.0 mm.

The surface of the housing 10 is provided with a dark coating 12 (shown by cross-hatching) such as black or gray so as to form an unpainted portion 13 around each opening 11 except for the periphery. . The width of the unpainted portion 13 formed around each opening 11 is desirably 0.05 to 0.3 mm. As a coating method, a precision (metal) screen or a photomask method of an ultraviolet curable resin can be used.

If the width of the unpainted portion 13 is smaller than 0.05 mm, ink dripping may occur in the opening 11.
Painting is also difficult. If it is wider than 0.3 mm, dark paint 1
There is a possibility that the portion 2 becomes narrow and the effect of improving the contrast by the dark paint 12 is reduced.

The LED dot matrix display unit using the present housing 10 is small in size, but has no ink dripping into the opening 11 and is excellent in display quality. The reason will be described with reference to FIG.

The left figure in FIG. 4A shows the luminance distribution when the entire surface of the housing is coated with a dark color, and the right figure feels when the person looks at it from the front. 3 shows a subjective brightness distribution.

The brightness distribution is such that the brightness is low at the so-called bank between the openings where the entire surface is coated, the brightness is high at the light emitting portion inside the hole, and the brightness continuously increases from the bank to the light emitting portion. Becomes As shown by the solid line in the figure on the right, the distribution of the subjective brightness is obtained by differentiating the brightness distribution.At the boundary between the bank and the opening, the darkness is emphasized to produce a minimal part, and the non-light emitting part in the opening The brightness is emphasized at the boundary between the light-emitting portion and the light-emitting portion to produce a local maximum. This is called the Mach effect.

If there is ink dripping in the opening, the minimum portion moves into the opening and the darkness of the ink dripping portion as shown by the chain line in the right figure of FIG. Moves downward because of strong On the other hand, the maximum part also changes due to variations in the brightness of the LED itself. Thus, the uneven brightness of the LED is increased by the ink dripping.

On the other hand, when an unpainted portion is provided around the opening, a second minimum portion is formed at the boundary between the painted portion and the unpainted portion on the bank, as shown in FIG. The minimum portion changes due to unevenness or protrusion of the coating, but the original minimum portion generated at the boundary between the bank and the opening is constant because it has not been coated.

Therefore, the difference between the minimum part and the maximum part is LE
It changes only due to variations in the brightness of D itself, and is not affected by the painting state. Thus, uneven brightness is not promoted by ink dripping, and as a result, uneven brightness is improved without lowering the brightness of the dark color coating, and display quality is improved.

Further, since the ink does not bulge at the peripheral edge of the opening 11, when a diffusion sheet or the like is stuck on the surface of the housing 10, the sheet uniformly adheres to the dark-colored coating 12, and Of the contrast due to the floating of the image is prevented.

Further, an LED using the present housing 10
In the dot matrix display unit, light emitted from the LED is reflected on the unpainted portion 13 and the reflected light is reflected on the LED.
Since it is assimilated with the light emitted from the light source, the effect that the area of the light emitting portion is widened and recognized can be expected.

In the above embodiment, the opening 11 is square, but may be a square or polygon with rounded corners, or even a round shape, and the shape is not limited.

[0026]

As described above, in the case of the light emitting display unit according to the present invention, the width of the portion where the dark paint is not applied around the opening is increased.
By setting the thickness to 0.05 to 0.3 mm , the ink does not drip into the opening and uneven brightness of the light emitting element is not promoted. Therefore, the brightness unevenness is improved without lowering the darkness of the dark color coating, and both the contrast and the brightness uniformity are achieved. In addition, the diffusion sheet or the like uniformly adheres to the dark-colored portion, and the contrast is prevented from lowering due to the floating of the sheet, so that the contrast is improved.

[Brief description of the drawings]

FIG. 1 is a front view and a sectional view showing a general structure of a housing used for a light emitting display unit.

FIG. 2 is an explanatory diagram of ink dripping and swelling.

FIG. 3 is a front view of a housing showing one embodiment of the present invention.

FIGS. 4A and 4B are a luminance distribution diagram and a subjective brightness distribution diagram for explaining the reason why luminance unevenness is improved in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Housing 11 Opening 12 Dark paint 13 Unpainted part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Open to the public 49-114884 (JP, U) Open to the public 555-120171 (JP, U) Open to the public 2-121784 (JP, U) Open to the public Showa 55- 71568 (JP, U) Japanese Utility Model Showa 55-164859 (JP, U) Japanese Utility Model Utility Model Showa 61-165578 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G09F 9/33 G09F 13 / 20 H01L 33/00

Claims (1)

(57) [Claims] 1. A light emitting device comprising: a plurality of light emitting elements arranged regularly on a substrate; and a housing having a plurality of apertures into which the light emitting elements are fitted. In a light emitting display unit that performs dot pattern display by selectively lighting the elements, the housing is made to be a bright color having a high reflection efficiency with respect to light emitted from the light emitting elements, and the periphery of each opening of the housing is excluded. The surface is dark-painted to improve contrast , and holes are opened.
Adjust the width of the surrounding unpainted parts to 0.05
A light-emitting display unit having a thickness of 0.3 mm .