Incremental printing of symbolic information – Thermal marking apparatus or processes – Specific resistance recording element type
Reexamination Certificate
2001-04-06
2004-02-03
Tran, Huan (Department: 2861)
Incremental printing of symbolic information
Thermal marking apparatus or processes
Specific resistance recording element type
Reexamination Certificate
active
06686945
ABSTRACT:
FIELD OF THE INVENTION
1. Technical Field
The present invention relates to a thermal head and a thermal head unit, which are used, for instance, in a miniature portable recording apparatus, a facsimile machine, a printer for tickets and receipts, etc, and also relates to a method of manufacturing the thermal head and the thermal head unit.
2. Background Art
A thermal head includes a head chip in which heating elements arrayed in a row and electrodes connected to these elements are provided on a ceramic substrate, and an IC chip serving as a driver for outputting print signals to selectively generate heat from desired heating elements at desired timings.
FIG. 19
shows an example of a thermal head unit in which the thermal head of this type is mounted onto a heat radiating plate to form a unit. The thermal head unit includes a thermal head
101
, and a heat radiating plate
102
made of aluminum or the like. The thermal head
101
is designed such that an electrode
104
and a heating element
105
are formed on a ceramic substrate
103
, and an IC chip
106
is further mounted thereon. The electrode
104
, a separately provided external terminal
107
for inputting external signals therein, and the IC chip
106
.are connected together through bonding wires
108
. The IC chip
106
and the bonding wires
108
are molded with sealing resin
109
.
To form aboard for the thermal head
101
of this type, a relatively large ceramic substrate
103
is used, and the electrodes
104
, the heating elements
105
and the like are formed as thin or thick films on the substrate
103
. For this reason, the board obtained by one board forming process is low in number, and thus the productivity is low.
To improve the productivity of the board forming process, it known to provide a composite substrate using a ceramic substrate reduced in size. That is, as shown in
FIG. 20
, in place of the ceramic substrate
103
, a ceramic circuit board
103
A and a wiring substrate
103
B such as a glass fabric based epoxy resin substrate (hereafter referred to as GE substrate when applicable) are used. In this case, the external terminal
107
is provided on the wiring substrate
103
B.
Although this approach makes it possible to improve the productivity of the board forming process, the handling ability is considerably reduced since the ceramic substrate
103
A and the wiring substrate
103
B are joined to the heat radiating plate
102
, and then the IC chip
106
is mounted thereon and the wire bonding is carried out therefor.
In view of the above problems, an object of the present invention is to provide a thermal head, a thermal head unit and a method of manufacturing the same, which can improve the productivity of a board forming process while improving the handling ability of a mounting process, thereby remarkably reducing the cost.
According to a first aspect of the present invention, to solve the above problems, a thermal head is characterized by comprising a head chip having one surface on which heating elements and electrodes connected to the heating elements are provided, and a semiconductor integrated circuit connected to the electrodes, the thermal head characterized in that a wiring substrate is provided, which is joined to the other surface of the head chip, and the semiconductor integrated circuit is mounted to the wiring substrate.
According to a second aspect of the present invention, in the first aspect of the invention, a thermal head is characterized in that one end side of the head chip in a width direction thereof is protruded from the wiring substrate.
According to a third aspect of the present invention, in the second aspect of the invention, a thermal head is characterized in that a protruded amount by which the head chip is protruded from the wiring substrate is 20% to 70% of a width of the head chip.
According to a fourth aspect of the present invention, in the first aspect of the invention, a thermal head is characterized in that the head chip is completely overlapped with and joined onto the wiring substrate.
According to a fifth aspect of the present invention, in the fourth aspect of the invention, a thermal head is characterized in that one end side of the wiring substrate is protruded from one end side of the head chip in a width direction thereof.
According to a sixth aspect of the present invention, in any one of the first to fifth aspects of the invention, a thermal head is characterized in that the semiconductor integrated circuit is mounted onto the wiring substrate to be substantially contacted with an end face of the head chip.
According to a seventh aspect of the present invention, in any one of the first to sixth aspects of the invention, a thermal head is characterized in that a height of a surface of the semiconductor integrated circuit is substantially the same as a height of a surface of the head chip.
According to an eighth aspect of the present invention, in any one of the first to sixth aspects of the invention, a thermal head is characterized in that a height of a surface of the semiconductor integrated circuit is lower than a height of a surface of the head chip.
According to a ninth aspect of the present invention, in any one of the first to eighth aspects of the invention, a thermal head is characterized in that a common electrode is provided, which extends in a longitudinal direction along an end portion of the head chip opposite from the heating elements in a width direction, and connection wirings connecting the common electrode to common electrode wirings provided to the wiring substrate are provided at plural locations in the longitudinal direction.
According to a tenth aspect of the present invention, in the ninth aspect of the invention, a thermal head is characterized in that each of the connection wirings connecting the common electrode provided to the head chip to the common electrode wirings provided to the wiring substrate are provided between physical blocks defined by the semiconductor integrated circuits.
According to an eleventh aspect of the present invention, in the tenth aspect of the invention, a thermal head is characterized in that the connection wirings connecting the common electrode provided to the head chip to the common electrode wirings provided to the wiring substrate are provided for the respective physical blocks defined by the semiconductor integrated circuits.
According to a twelfth aspect of the present invention, in the any one of the ninth to eleventh aspects of the invention, a thermal head is characterized in that at least one connection wiring connecting the common electrode provided to the head chip to a common electrode wiring provided to the wiring substrate is provided within the physical block defined by the semiconductor integrated circuit.
According to a thirteenth aspect of the present invention a thermal head unit is characterized in that the thermal head in any one of the first to twelfth aspects is mounted to a support member.
According to a fourteenth aspect of the present invention, in the thirteenth aspect of the invention, a thermal head unit is characterized in that one end portion of the head chip in the width direction, which serves as a heating element forming portion, is protruded from the wiring substrate, the support member is formed with an upper step portion to which the heating element forming portion is joined, and a step difference portion recessed more deeply than a thickness of the wiring substrate, and an adhesive agent layer is provided in a clearance that is formed between the step difference portion and the wiring substrate when the heating element forming portion of the head chip is joined to the upper step portion.
According to a fifteenth aspect of the present invention, in the fourteenth aspect of the invention, a thermal head unit is characterized in that an adhesive layer is provided for joining the heating element forming portion of the head chip to the upper step portion, and the adhesive agent layer is softer than the adhesive layer after the heating element forming portio
Ito Taro
Nakamura Yuji
Sambongi Norimitsu
Shoji Noriyoshi
Takizawa Osamu
Adams & Wilks
Seiko Instruments Inc.
Tran Huan
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