Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure – With housing or contact structure
Reexamination Certificate
2000-04-27
2003-09-30
Fahmy, Wael (Department: 2814)
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
With housing or contact structure
C257S100000, C257S101000, C257S098000
Reexamination Certificate
active
06627922
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a chip-type semiconductor light emitting device in which a light emitting element chip is bonded on an insulation substrate, and light is applied in a direction parallel to the surface of the insulation substrate, namely, in a direction of a side surface of the device. More particularly, the invention relates to a chip-type light emitting semiconductor light emitting device which emits from a side surface, and is capable of widening a directivity so that a portion which is referred to as a dark decreases where light is not allowed to be incident on a light transmitting plate even with the widening of a interval of the light emitting devices even in the case where light source is adopted which allows light to be incident on a light transmitting plate which serves, for example, as a backlight of a liquid crystal display device.
BACKGROUND OF THE INVENTION
A chip-type semiconductor light emitting device which is generally used is constituted in such a manner that light is emitted toward an upper surface side by bonding a light emitting element(diode) chip(hereinafter referred to as an LED chip) on an insulation substrate and covering on the periphery of the LED chip with a light transmitting resin. However, since it is required to install a light source on a side of a plate-like light transmitting plate, for example, as a light source for allowing light to be incident on the light transmitting plate of the backlight of the liquid crystal display device, a lamp-type light emitting device is conventionally used. However, these days, a so-called side surface emitting chip-type light emitting device(chip-type light emitting device which emits from the side face) is used in which the chip-type light emitting device is allowed to emit light in a direction parallel to the insulation substrate. Such side surface emitting chip-type light emitting device has a structure, for example, as shown in FIG.
4
.
In
FIG. 4
, reference numeral
21
denotes an insulation substrate formed of, for example, a glass epoxy or the like. On the sides of both end portions of the insulation substrate
21
, conductive films are provided, and a pair of electrodes
22
and
23
are formed thereon. On the surface of the insulation substrate, an LED chip
24
is bonded and is electrically connected to the pair of the electrodes
22
and
23
by wire
25
or the like (in an example shown in
FIG. 4
, one of the electrodes of the LED chip
24
is formed on the rear surface side thereof and is directly connected to the electrode
22
with the bonding paste). Furthermore, the periphery thereof is covered with a light transmitting resin
26
. Furthermore, the external circumference of the resin
26
is covered with a case
27
formed of a light shielding material having a light reflecting characteristic. Incidentally, the chip-type semiconductor light emitting device has a structure constituted in such a manner that a through holes
21
a
are provided on both end portions of the insulation substrate
21
, the electrodes
22
and
23
are connected to the rear surface of the substrate
21
with a conductive films provided inside of the through holes
21
a
, and printed substrate, mother board or the like to be electrically connected.
In the case where such light emitting device is installed on the side surface of the light transmitting plate to constitute a backlight, as shown in
FIG. 5
, the chip-type light emitting device has a structure constituted in such a manner that a side surface emitting chip-type light emitting device
20
is arranged on one side wall of the light transmitting plate
30
in a definite interval, light is allowed to be incident on the inside of the light transmitting plate
30
and is allowed to be scattered within the light transmitting plate
30
to allow light to be applied from the surface the light transmitting plate
30
.
As described above, the conventional side surface emitting chip-type light emitting device is formed in such a manner that a light transmitting resin is allowed to be exposed only on one side surface of the insulation substrate having a rectangular shape so that light is allowed to be applied in a direction parallel to the substrate from one side surface of the insulation substrate. Then, the surfaces other than the one side surface is formed in such a manner that the light transmitting resin is completely covered with the case
27
to allow light to be applied only from the side of the one side surface with the result that the emitted light is effectively used and the efficiency of the light emitted to outside can be improved. Consequently, the chip-type light emitting device has a structure such that the exposed portion of the light transmitting resin and the bottom portion on the opposite side thereof has a concave shape in the case, and an LED chip is placed on the bottom portion side with the result that light is applied from an open portion of the case
27
.
As a consequence, a bundle of light that is radiated from one side surface is such that a strong light is emitted in a central direction and the directivity thereof is narrowed down. As a consequence, as shown in
FIG. 5
, when light emitting devices are arranged in a definite interval on a side surface of the light transmitting plate
30
, a portion which is referred to as a dark portion
31
is generated in which light is not allowed to be incident at a portion of the light transmitting plate
30
between the light emitting devices
20
. A portion of such dark portion
31
is compensated with light which is reflected and brought back within the light transmitting plate
30
, but the dark portion
31
has a problem such that the portion has a different luminance from a portion on which light is directly allowed to be incident so that the luminance does not become uniform on the entire surface of the light transmitting plate
30
.
In order to solve such a problem, the interval between the light emitting devices must be narrowed down with an increase in the number of the light emitting devices with the result that the production cost will increase.
SUMMARY OF THE INVENTION
The present invention has been made to solve such a problem, and an object of the invention is to provide a side surface emitting chip-type semiconductor light emitting device having a wide directivity wherein a dark is hardly generated between light sources in the case where the light sources for use in backlights are arranged in a definite interval.
Another object of the present invention is to provide a side surface emitting chip-type semiconductor light emitting device which can be manufactured at simple steps wherein bending of wires is not generated at the manufacturing stage so that a good quality light emitting device can be provided.
The chip-type semiconductor device according to the present invention comprises:
a rectangle-shaped insulation substrate on which a pair of electrodes are provided;
a light emitting element chip provided on the insulation substrate, the device having an n-side electrode and a p-side electrode connected to the pair of electrodes respectively;
a light transmitting member being provided on the insulation substrate and covering the periphery of the light emitting element chip; and
a light reflection member covering at least a part of the light transmitting member, the light reflection member being provided to radiate light from the portion of the light transmitting member which is not covered and exposed;
wherein the above light reflection member is formed in such a manner that the portion of the light transmitting member which is not covered with the light reflection member and is exposed is exposed over from one side in the rectangle shape to at least a part of the side portions on both sides which continue to the one side.
Here, the light transmitting member refers to a material which transmits light which is emitted with the light emitting element chip. The material is not required to be transparent. A material which transmits light while scatteri
Arent Fox Kintner & Plotkin & Kahn, PLLC
Fahmy Wael
Ha Nathan W.
Rohm Co. Ltd
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