LED display panel structure

An LED display panel structure comprises a PC board, a front plate having a plurality of through-holes defined thereon, a plurality of washers, each of which is provided on a back surface of the front plate in correspondence with each of the through-holes, a plurality of LEDs, each of which is inserted through a central aperture of each of the washers being smaller than a diameter of the LED to be clamped therein, and a plurality of holders, each of which has a first recess and a second recess, each of the holders receives and holds each of the LEDs in its first recess and is attached on the PC board by water resistant adhesive filled in the second recess. A pair of through-bores communicating the first recess with the second recess are defined therebetween to allow a pair of leads of each of the LEDs to extend therethrough and connect to the PC board. Such a structure can prevent moisture from seeping in to damage the LEDs.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an LED display panel, more particularly, 
to an LED display panel structure with high water resistance. 
2. Description of Related Art 
LED display panels are widely used now throughout the world in all manner 
of situations. For example, it is used as an informational sign for 
showing traffic condition, or as a bill board for publicizing merchandise. 
A conventional LED display panel as shown in FIG. 4 includes a casing 72, a 
PC board 70 supported on the casing 72, a plurality of LEDs 71 provided on 
the board 70, and a transparent acrylic plate 73 provided in front of the 
LEDs 71. However, there is always a gap existing between respective edges 
of the acrylic plate 73 and the PC board 70, so it is possible that 
moisture seeps into a space defined therebetween via the gap, resulting in 
a mist on the acrylic plate 73, whereby causing a degradation for 
visibility of the display panel. 
In addition, there is a reflection phenomenon due to acrylic plate 73, 
resulting in a reduced contrast of the. LEDs 71, so the visibility of the 
display panel is degraded accordingly. A conventional method used to 
overcome this problem is to increase a current passing through the LEDs 
71, so as to enhance light intensity thereof. However, such a manner using 
a large current causes a diminution of life-time of an LED. 
Furthermore, the LEDs 71 are inserted on the PC board 70 directly, however, 
it is difficult for the LEDs 71 to be secured on the board 70 by such a 
manner. An inclination often occurs to some of the LEDs 71 when the 
display panel is subjected to an external force, and therefore resulting 
in negative influence on the visibility of the display panel. In addition, 
a space between the acrylic plate 73 and the LEDs 71 is very small because 
the LEDs 71 are inserted on the PC board 70 directly. The space is not 
sufficient for dissipating a heat due to a process of passing the display 
board through a tinning machine, and therefore resulting in a 
disadvantageous effect on the LEDs. 
SUMMARY OF THE INVENTION 
One object of the present invention is to provide an improved LED display 
panel structure having high water resistance to prevent the LEDs arranged 
on the display panel from being damaged by moisture and avoid degradation 
of visibility of the display panel. 
Another object of the present invention is to provide an improved LED 
display panel structure, which presents good heat dissipation effect, and 
therefore increasing the life-time of each LED. 
A further object of the present invention is to provide an improved LED 
display panel structure, which can avoid inclination of the LEDs disposed 
on the display panel to maintain the visibility thereof at a certain 
level. 
In accordance with one aspect of the present invention, the LED display 
panel structure comprises a PC board, a front plate having a plurality of 
through-holes defined thereon, a plurality of washers, each of which is 
provided on a back surface of the front plate in correspondence to each of 
the through-holes, a plurality of LEDs, each of which is inserted into a 
central aperture of each of the washers and the corresponding through-hole 
to be secured therein, and a plurality of holders having a first recess 
and a second recess applied with water resistant adhesive, each of which 
holds each of the LEDs in its first recess and is disposed on the PC 
board, thereby preventing moisture from seeping to damage the LED. 
In accordance with another aspect of the present invention, the heat 
dissipation effect of the LED display panel can be improved since the 
holder holding the LED and being disposed on the PC board allows the LED 
not to be disposed on the PC board directly so as to provide a spacing 
between the LEDs and the PC board, and there is no need for an acrylic 
plate to be provided in front of the LEDs. Accordingly, the LED can be 
protected from being damaged by heat when the PC board is processed by a 
tinning machine. 
In accordance with a further aspect of the present invention, the LED 
display panel structure further comprises a plurality of supports for 
fixing the PC board with the front plate to secure the holder holding the 
LED, so as to prevent the inclination of the LED. 
Other objects, advantages and novel features of the invention will become 
more apparent from the following detailed description when taken in 
conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
Now referring to FIG. 1, the LED display panel structure comprises a front 
plate 60, which has a plurality of through-holes 61 defined therein, each 
of the through-holes 61 being correspondingly provided with a washer 10 at 
the back side of the front plate 60, a plurality of LEDs (light emitting 
diodes) 20, each having two leads 21 extending from a body thereof, 
wherein a respective LED is inserted into a central aperture of the washer 
10 and the corresponding through-hole 61. The LED 20 is clamped securely 
by the washer 10, since the aperture of the washer 10 is slightly smaller 
than a diameter of the LED 20. By such a matter, the LED 20 can be tightly 
and firmly combined With the washer 10, and therefore preventing water 
such as moisture from seeping in to damage the LED. 
As shown in FIG. 1, a holder 30 having a first recess 31 and a second 
recess 32 is provided to receive and hold each of the LEDs 20 in the first 
recess 31 thereof, wherein a pair of through-bores 34 communicating the 
first recess 31 with the second recess 32 are defined therebetween, as 
shown in FIG. 1 and FIG. 2, to allow the two leads 21 to extend 
therethrough, respectively. The LED 20 is applied with water resistant 
adhesive at a portion where the leads extend therethrough before being 
held in the first recess 31 of the holder 30. There are a plurality of 
slits 33 defined on the peripheral wall around the second recess 32 as 
shown. The second recess 32 and the slits 33 are filled with water 
resistant adhesive 35 (see FIG. 2), and then each of the holders 30 
holding the LED 20, which is clamped by the washer 10, is combined to a PC 
board 40, and the two leads of each of the LEDs are accordingly connected 
thereto. The structure formed as above can effectively prevent the leads 
of each of the LEDs from being contacted by moisture, that is, it exhibits 
a good water resistance. 
Since each of the LEDs 20 is held in each of the holders 30 and then 
secured on the PC board 40 rather than directly secured thereto as in 
prior art, thus there exists a spacing between the LED 20 and the PC board 
40. Therefore, the LED is not subjected to heat when the PC board 40 is 
processed by a tinning machine, so as to maintain the life-time of the 
LED. 
Furthermore, a support 50 having a plurality of bores 51 defined thereon is 
fixed to the PC board 40 by a bolt 52 extending through each of the bores 
51 and a respective corresponding bore 41 in the PC board 40, and then 
secured to the front plate 60 by the same bolt 52 threadedly engaging with 
a projection 62 with threaded bore defined inside provided on the front 
plate 60, as shown if FIG. 3. As a result, the front plate 60 and the PC 
board 40 are secured together with each of the holders 30 holding each of 
the LEDs 20 sandwiched therebetween, and therefore preventing the LEDs 20 
from unintentional inclination. In addition, the result structure can be 
provided in a casing 63, as shown in FIG. 2. 
It is to be understood, however, that even though numerous characteristics 
and advantages of the present invention have been set forth in the 
foregoing description, together with details of the structure and function 
of the invention, the disclosure is illustrative only, and changes may be 
made in detail, especially in matters of shape, size, and arrangement of 
parts within the principles of the invention to the full extent indicated 
by the broad general meaning of the terms in which the appended claims are 
expressed.