JPH01118494A - Ic card - Google Patents

Abstract

PURPOSE: To positively display the arrival of the termination of a cell life by providing an insulating substrate, a printed character layer, a filmy liquid crystal layer and its protecting layer on an alarm unit part for a drop in the voltage through detecting a drop in the voltage of a cell and energizing the printed character layer to generate a heat when a signal for detecting the drop of the cell voltage is output. CONSTITUTION: An alarm unit 1 for a drop in the voltage has a zigzag pattern character 3a, formed on a substrate 2, on which a liquid crystal layer 4 in the form of a film is laminated using an adhesive, with a protecting layer 5 coated on the liquid crystal layer 4. In addition, the output terminal of a circuit element 8 for detecting a drop in the cell voltage is connected to an input terminal for the zigzag pattern character 3a of a resistor through connecting parts 8a, 8b. When the circuit element 8 detects the drop in the voltage of the cell 11, the character 3a is displayed on the face of a panel. That is, the voltage is detected using a voltage drop detection part 8d, then this detection data is entered to a control part 8e and the control part 8e turns a switch 8f ON under control or performs the ON/OFF control of the switch 8f when the voltage drops below a specified reference value. Thus the character 3a is energized to generate a heat.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an IC card, and particularly to an IC card in which a battery voltage drop detection function is added to the card itself.

[Prior Art] Usually, an IC card contains semiconductor devices such as a memory, a timer element, and a microprocessor, and a replaceable battery.

However, conventional IC cards do not have a voltage drop detection means for the stored battery, and to detect a voltage drop in the internal battery, the battery voltage is output to one terminal of the external connection terminal of the IC card, and this terminal voltage is transferred to the IC card. This was done by monitoring the equipment used.

[Problems to be Solved] As described above, conventional IC cards cannot detect a drop in battery voltage by themselves.

For example, if the IC card is left alone, or if the device is powered off even though the IC card is connected to the device, even if the internal battery is nearing the end of its lifespan and the voltage begins to drop, this will not occur. There was a problem in that it was not possible to detect the battery in advance and replace the battery.

The present invention was made in view of such conventional problems, and its purpose is to realize an IC card that can accurately detect a drop in internal voltage and display this to the user. be.

[Means for Solving Problems] In order to achieve the above object, the present invention provides: a battery voltage drop detection circuit that detects a voltage drop in a built-in battery of an IC card; and a battery voltage drop detection circuit that detects a voltage drop on the card surface when a battery voltage drop is detected. a voltage drop warning unit section that displays warning characters; the voltage drop warning unit section includes an insulating substrate with low thermal conductivity; and printed characters formed on the substrate using a thick film resistor heater. layer, a film-like liquid crystal layer coated on the surface of this character layer, and a protective layer coated on this liquid crystal layer, and placed on the IC card substrate so that its surface side coincides with the surface of the IC card. The printed character layer is fixed and is configured to be heated by energization when a battery voltage drop detection signal is output from a battery voltage drop detection circuit.

[Example] Next, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a preferred example of the IC card according to the present invention, and the IC card of the embodiment is provided with a voltage drop warning unit 1 that warns of a voltage drop in the internal battery.

FIG. 2 shows the internal structure of the IC card of this embodiment, in which the voltage drop warning unit 1 is held and fixed on the IC circuit board 6 using a suitable spacer 12.

In the embodiment, this voltage drop warning unit 1 includes a third
As shown in the figure, fine zigzag pattern characters 3a of a thick film resistor are formed by printing on a substrate 2 of low thermal conductivity, such as epoxy resin containing glass resin, and a liquid crystal layer on a film is formed on the substrate 2. 4 is adhesively laminated, and a protective layer 5 is further coated thereon.

This voltage drop warning unit 1 is formed so as to mesh with a panel]-0 that protects the surface of the card as shown in FIG. 1, and a battery voltage drop detection circuit element 8 shown in FIG. , when a voltage drop of the battery 11 is detected, the characters 3a are displayed so as to appear on the surface of the panel 10.

In the embodiment, the voltage drop detection unit 1 and the battery voltage drop detection circuit element 8 are connected by connecting the connecting portions 8a and 8b provided at both ends of the connecting element 8c to the circuit board 6, respectively.
This is done by crimping or soldering the terminals provided on the side and the terminals provided on the resin substrate side.

Further, in this embodiment, in addition to the battery voltage drop detection circuit element 8 described above, a semiconductor device 9 such as a memory and an external connection connector 7 are mounted on the circuit board 6, and the battery voltage drop detection circuit is mounted on the circuit board 6. The battery voltage is input to the element 8 via the contact terminal 11a of the battery 11.

Further, the output terminal of the battery voltage drop detection circuit element 8 is connected to the resistor zigzag pattern character 3a via the connection parts 8a and 8b.
is connected to the input terminal of

FIG. 3 shows the cross-sectional internal structure of the IC card of this embodiment.

The figure also shows that a printed character layer 3 made of a thick film resistor is formed on the implementation substrate, and a film-like liquid crystal layer 4 and a protective layer 5 are formed on this.
It will be more clearly understood that the voltage drop warning unit 1 of the embodiment is constructed by laminating the following.

In FIG. 4, I
C. The circuit block of the card is shown.

The battery voltage drop detection circuit element 8 of the embodiment includes a voltage drop detection section 8d, a switch control section 8e, and a switch 8f.

Then, the voltage of the battery 11 is detected using the voltage drop detection section 8d, and the detection signal is inputted to the switch control section 8e.

The switch control unit 8e controls the switch 8f to turn on when the battery voltage drops below a predetermined reference value based on the detection signal.
Or control it on and off intermittently.

As a result, the fine zigzag pattern character 3 of the thick film resistor
A is energized, and the pattern character 3a generates heat continuously or intermittently.

Next, the principle of character display according to the present invention will be explained using FIG.

As shown in FIG. 5(a), the fine zigzag pattern letters 3a of the thick film resistor are formed on a resin substrate with low thermal conductivity, and when heat is generated by electricity, the fine zigzag pattern letters 3a are Heat only the immediate area.

By the way, since the film-like liquid crystal has a property that its refractive index changes with heat, when the film-like liquid crystal layer 4 is coated on the zigzag pattern characters 3a as in the present invention,
As shown in FIG. 5(b), only the heated character portion becomes a region 3b which has a different color or reflection from other low temperature regions, and a message consisting of a series of character patterns can be exuded on its surface.

Therefore, by visually checking the message displayed in this way, you can smoothly replace the battery.
This makes it possible to prevent the loss of card contents.

In addition, in the present invention, when electricity is intermittently applied to the fine zigzag pattern characters 3a of the thick film resistor, the message is displayed slowly, so that the life of the built-in battery 11 is extended and the message is displayed for a long time. It can be performed.

[Effects of the Invention] As explained above, according to the present invention, when a drop in battery voltage is detected, the fine zigzag pattern characters on the thick film resistor are heated by electricity, and the voltage drop warning characters are raised on the liquid crystal layer by this heat. By having a structure that allows the IC card to be lifted up, for example, even when the IC card is placed alone, or even when the IC card is installed in the device but the power to the device is turned off,
Since the end of battery life can be reliably detected and displayed, it is possible to realize an IC card that allows smooth battery replacement and prevents loss of card contents.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view of a preferred example of the IC card according to the present invention, FIG. 2 is a perspective view showing the internal structure of the IC card shown in FIG. 1, and FIG. 3 is a perspective view of the IC card shown in FIG. 1. 4 is a block circuit diagram showing the circuit configuration of the IC card shown in FIG. 1; FIG. 5 is a diagram explaining the principle of character display by the voltage drop warning unit. 1: Voltage drop warning unit 2: Resin substrate 3: Fine zigzag pattern letters of thick film resistor 4: Film liquid crystal layer 5: Protective layer 6: Circuit board 11: Battery

Claims (1)

[Claims] (1) A battery voltage drop detection circuit that detects a voltage drop in the built-in battery of an IC card; and a voltage drop warning unit that displays voltage drop warning characters on the card surface when a battery voltage drop is detected; The voltage drop warning unit section includes an insulating substrate with low thermal conductivity, a printed character layer formed on this substrate using a thick film resistor heater, and a film-like coating formed on the surface of this character layer. a liquid crystal layer; a protective layer formed on the liquid crystal layer;
1. An IC card, wherein the printed character layer is fixed on a C card substrate and is heated by electricity when a battery voltage drop detection signal is output from a battery voltage drop detection circuit.