Target for laser cathode ray tube and fabrication method...

Details Target for laser cathode ray tube and fabrication method... Target for laser cathode ray tube and fabrication method...

1999-05-28

2001-05-29

Le, Que T. (Department: 2878)

Radiant energy

Photocells; circuits and apparatus

Photocell controlled circuit

C250S2140LA, C313S376000

Reexamination Certificate

active

06239420

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a target for a laser cathode ray tube (CRT) with improved efficiency by improving an adhesion layer for adhering a laser projecting portion and a radiation layer to each other, and a fabrication method thereof.
2. Description of the Related Art
In general, a conventional laser CRT includes a tube in which an electron gun is installed, a bulb integrally welded with the tube and a target portion for generating a laser beam by collision of electron beams emitted from the electron gun.
FIG. 1
shows a target
10
for a conventional laser CRT, including a laser projecting portion
11
, a radiation layer
12
and an adhesion layer
15
.
The laser projecting portion
11
is comprised of a semiconductor layer
13
made of a single crystal such as CdS, CdSSe or ZnSe, and first and second mirrors
14
a
and
14
b
respectively fixed on the bottom and top surfaces of the semiconductor layer
13
. The radiation layer
12
is made of sapphire so that the heat generated from the laser projecting portion
11
is conducted and emanated.
The first mirror
14
a
of the laser projecting portion
11
is adhered to the radiation layer
12
by the adhesion layer
15
. Here, the adhesion layer
15
serves to transmit the heat generated from the laser projecting portion
11
to the radiation layer
12
and acts as a buffer layer when polishing a surface of the semiconductor layer
13
. Also, the adhesion layer
15
maintains the flatness of the laser projecting portion
11
during the polishing process. A laser generated from the laser projecting portion
11
is transmitted through the adhesion layer
15
.
During the operation of the conventional laser CRT, when a voltage is applied to an electron gun (not shown), an electron beam is emitted from the electron gun to the laser projecting portion
11
. The electron beam impinges on the semiconductor layer
13
to thus excite electrons, thereby generating light. The generated light resonates between the first and second mirrors
14
a
and
14
b
and is emitted as a laser beam. Then, the laser beam penetrates the radiation layer
12
and is projected onto a screen through a lens (not shown).
Here, the heat generated from the semiconductor layer
13
is conducted to the radiation layer
12
through the adhesion layer
15
to then be emitted to the outside. Conventionally, transparent epoxy glue having a shear stress of 1 Kg per unit area, has been used as the adhesion layer
15
. The adhesiveness and light transmittance of the optical glue tend to be noticeably reduced at a temperature of 150° C. or higher. Thus, the processing or driving temperature at which the laser CRT is driven is limited to the range of −200~150° C.
During fabrication of a laser CRT, the inside of the laser CRT must be maintained at a high-vacuum state while being applied to a high-temperature furnace. However, since the upper limit temperature is limited to the above temperature range, it is rather difficult to achieve a high-vacuum state.
Also, while a laser CRT is driven, since an adhesion layer cannot withstand heat immediately applied by electrons at a high voltage, the degree of the vacuum state of a bulb is lowered.
SUMMARY OF THE INVENTION
To solve the above problems, the present invention provides a target for a laser CRT having an improved adhesion layer for adhering a laser projecting portion and a radiation layer to each other, and a fabrication method thereof.
Accordingly, to achieve the above objective, there is provided a method for fabricating a target for a laser cathode ray tube including the steps of (a) polishing one plane of a semiconductor layer, (b) forming a first mirror on the polished plane of the semiconductor layer, (c) forming an adhesion layer made of a bisbenzocyclobutene solution on top of a radiation layer, (d) adhering the adhesion layer and the first mirror to each other, (e) polishing the other surface of the semiconductor layer, and (f) forming a second mirror on the other surface of the semiconductor layer.
According to another aspect of the present invention, there is provided a target for a laser cathode ray tube including a laser projecting portion comprised of a semiconductor layer, and first and second mirrors formed on bottom and top surfaces of the semiconductor layer, a radiation layer from which the heat generated from the semiconductor layer is emitted to the outside, and an adhesion layer interposed between the laser projecting portion and the radiation layer and formed of a bisbenzocyclobutene solution.


REFERENCES:
patent: 6146992 (2000-11-01), Lauterbach et al.

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