Focus unit of fly back transformer

Details Focus unit of fly back transformer Focus unit of fly back transformer

1999-03-19

2001-01-09

Easthom, Karl D. (Department: 2832)

Electrical resistors

Mechanically variable

Movable contact electrically adjustable over length of...

C338S162000, C338S202000, C338S184000

Reexamination Certificate

active

06172594

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fly back transformer (to be called “FBT” below) which generates a high voltage to supply it to a TV or a monitor. Particularly, the present invention relates to a focus unit of an FBT, which is installed on a side of the FBT, so that the focus and screen voltages can be adjusted. More specifically, the present invention relates to a focus unit of an FBT, in which the filling and curing of an insulating resin are eliminated. That is, a ceramic substrate with a resistor pattern formed thereon is installed within a cover through which an actuation knob of the focus unit passes. A slider is installed at an end of a volume shaft, and the volume shaft is formed integrally with the actuation knob, while a central contact of the slider contacts to a central terminal which is formed within the case, the case being facingly coupled with the cover. Further, a variable contact of the slider contacts to the resistor pattern of the ceramic substrate, so that a volume control can be carried out. Further, the ceramic substrate which is installed within the focus unit and on which the resistor pattern is printed is installed within the cover of the focus unit, and separated from an FBT case within which bobbins are installed. Therefore, the filling and curing of an insulating resin becomes needless.
2. Description of the Prior Art
In the generally known conventional FBT, the low voltage and high voltages bobbins generate a high voltage, and this high voltage is supplied through an anode cable to a cathode ray tube. Under this condition, the focus unit which is installed on a side of the FBT case varies the focus voltage and the screen voltage through a volume slider.
This conventional focus unit of the FBT is constituted as shown in FIG.
1
. That is, a rotating piece
54
is installed within a main body
52
of the focus unit
51
, and is connected to a focus and screen adjusting handle
53
. On the top of the rotating piece
54
, there is installed a slider
55
which has two contact points
56
and
56
′. A substrate
58
on which a circuit pattern
57
having variable and central contact points
57
a
and
57
b
is printed is installed in such a manner that the contact points
57
a
and
57
b
are connected to the contacts
56
and
56
′ of the slider
55
. From the substrate
58
, there protrudes an output pin
59
, and the substrate
58
is insulated by coating an insulating resin
60
.
In the conventional focus unit
51
constituted as described above, if the focus and screen voltages are to be varied, the focus and screen adjusting handle
53
is turned. Then the slider
55
is rotated together with the rotating piece
54
to vary the voltages. Under this condition, the slider
55
has two contacts
56
and
56
′, and one of them (
56
) is connected to the variable contact
57
a
of the circuit pattern
57
of the substrate
58
, thereby stepping up or down the focus and screen voltages. Meanwhile, another (
56
′) of the contacts is connected to the central contact
57
b
, so that an output can be drawn through a resistor.
However, in this conventional focus unit
51
, the slider
55
which is installed above the handle
53
has two contacts
56
and
56
′ for stepping up or down the focus and screen voltages. Further, the circuit pattern
57
of the substrate
58
has variable and central contacts
57
a
and
57
b
, so that these contacts can be made to be connected to the contacts
56
and
56
′. Thus the structure is very complicated, and the contacts might not be electrically connected, these being serious disadvantages.
Further, the substrate
58
having the circuit pattern
57
is disposed at the rear side of the focus unit, and therefore, the circuit pattern
57
is disposed near to the bobbins from which the high voltage is drawn. Therefore, the insulating characteristic is very weak. In order to overcome this problem, the substrate
58
is coated with an insulating resin, this being a troublesome task.
SUMMARY OF THE INVENTION
The present invention is intended to overcome the above described disadvantages of the conventional technique.
Therefore it is an object of the present invention to provide a focus unit of an FBT, in which a ceramic substrate with a resistor pattern printed thereon is installed within a cover of the focus unit, so that the ceramic substrate can be separated from a case of bobbins, thereby making it needless to fill an insulating resin into the focus unit and to cure the resin.
In achieving the above object, the focus unit of an FBT according to the present invention includes: a focus unit cover having two through holes for passing volume shafts of actuation knobs; each of the volume shafts being formed integrally with the actuation knob, and passing through each of the through holes; a substrate installed on an inside of the focus unit cover, and having a resistor pattern on an upper face of the substrate; a slider installed on an upper end of the volume shaft, and having a central contact and a variable contact for adjusting a voltage volume by contacting with the resistor pattern of the substrate; and a case facing toward the cover, and having a central terminal so as to contact with the central contact of the slider.


REFERENCES:
patent: 3631371 (1971-12-01), Maurice
patent: 5105128 (1992-04-01), Choi
patent: 5321385 (1994-06-01), Rilling
patent: 5726625 (1998-03-01), Hasebe et al.
patent: 5920252 (1999-07-01), Nakagawa
patent: 5923241 (1999-07-01), Garvalos
patent: 98-065047 (1998-10-01), None

Affiliated with

Also associated with

Rating

Focus unit of fly back transformer does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Focus unit of fly back transformer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Focus unit of fly back transformer will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2457832