Background Art The typical conventional fake banknote detector is comprised of UV emitting lamps, of which size is 120mm long with 20 mm in diameter as well as UV sensors. The above UV sensors detect and measure the amount of UV ray reflected from fluorescent material on the banknote and validate the banknote using the measured data because generally fake ones do not have fluorescent material on them.

However, due to rapid development in printing technology of fluorescent material on fake banknotes, we can say that it is no longer sufficient to verify it by the existing technology. Moreover, the size of UV emitting lamp is too big to make a compact type fake banknote detector. On top of this, relatively expensive fluorescent ray sensors

indispensable to the existing technology make production cost higher.

Disclosure of Invention The present invention is designed to solve above problems by employing small UV LEDs and inexpensive W sensors. We found that UV ray passes through authentic banknote while it does not pass through fake banknote paper but it is reflected. Therefore we can detect fake banknotes by measuring UV ray passed through the banknotes. With this technology of employing small UV LEDs and inexpensive UV sensors, more precise detection of fake banknote is possible with compact type fake banknote detection system at lower production cost.

Brief Description of Drawings Fig 1 shows the side view of PCBs with compact type UV LEDs and UV sensors according to the present invention; Fig 2 shows the ground view of PCBs with ultraviolet LEDs and UV sensors according to the present invention; Fig 3 is the side view of the fake banknote detector according to the present invention showing interactive processes in operation; Fig 4 is the brief diagram showing banknote detection processes with the fake banknote detector according to the present invention; and

Fig 5 is the flow chart showing overall banknote validation processes with the banknote detector according to the present invention..

***Explanation of Reference numerals designating the Major Elements of the Drawings*** 1. 1'Printed Circuit Board 2 UV LEDs 3 UV sensors 4 Hole for receiving UV ray passed through banknote 5 Inlet of banknote 6 : Outlet of banknote 7 : Banknote Best Mode for Carrying Out the Invention Now, preferred embodiments of the present invention will be described in detail with reference to the annexed drawings.

Fig 1 shows the side view of a fake banknote detector according to the present invention with UV LEDs and UV sensors, and Fig 2 is the ground view of a fake banknote detector according to the present invention with UV LEDs and UV sensors Fig 3 is the side view of the fake banknote detector according to the present invention showing interactive processes in operation, and Fig 4 is a brief diagram showing banknote validation processes. Fig 5 is the flow chart showing overall banknote validation

processes with the fake banknote detector according to the present invention.

The fake banknote detector according to the present invention comprising: a UV emitting unit with one or more UV LEDs (2) which are mounted on PCBs (1) (1') on both sides; one or more holes (4) perforated through PCBs (1) (1') to pass or deter UV emitted from UV emitting unit through the introduced banknote; a UV detecting unit with one or more UV sensors (3) which are mounted on PCBs (1) (1') on both sides and detect and measure the amount of passed UV ray through the banknote; and a control unit carrying out the comparison of the amount of passed UV ray through the banknote to the stored data of authentic banknote, and transmitting the result of comparison to display unit and communication unit to display the result and either to validate or reject the banknote.

The function of fake banknote detector according to the present invention is described below.

To operate the fake banknote detector, power supply should be made in order to activate several UV LEDs (2), UV sensors (3), and the other moving parts as well (S10).

As shown in Fig 3, while a banknote (7) is incoming through inlet gate (not shown) of the detector housing (not shown) and passes through the inlet of banknote (5) and travels to outlet of banknote (6) between PCBs (1) (1'), UV ray from UV LEDs (2) falls on the banknote (7) through the holes (4). And the UV ray passes the banknote in case of authentic one. The amount of UV ray passed through the banknote is detected and

measured by optical UV sensors (3), which will provide the measured data to the control unit (CPU) and the CPU transmit the data to the communication unit (S20).

The CPU receives signal of measurement result from UV sensors (3) and compare it with the stored data of authentic banknote (S30).

If the amount of UV ray measured is bigger than the stored data, the CPU compares the other data and validates the banknote (S50). And in case of acceptance, CPU transmits a signal allowing discharge of the banknote and asking further input of another banknote for validation (S60).

And in case the amount of UV ray measured is smaller than the stored data, CPU transmits a signal rejecting the banknote (S70).

It is possible because UV passes through authentic banknote while it does not pass through fake banknote paper but it is reflected. Therefore we can detect fake banknote by measuring UV passed through the banknote. The authentic banknotes transmit most of the UV ray from the UV LEDs (2), so the amount of UV ray detected by UV sensors (3) is larger than the stored data of authentic banknote. On the contrary, the fake banknotes reflect most of the UV rays from the UV LEDs (2), and the amount of UV ray detected by UV sensors is smaller than the stored data of authentic banknote.

As a result, in the present invention we can detect fake banknotes with compact detector system at lower production cost by employing small UV LEDs (2) and UV sensors (3).

And more precise detection of fake banknote is possible by validating the banknote

detecting the amount of UV ray transmitted through the banknote.

Industrial Applicability As explained above, the present invention adopts comparatively low priced UV LEDs and UV sensors, which are mounted in the opposite direction to emit UV ray and to receive it for measurement of passed amount of UV ray through banknote based on the fact that UV ray passes authentic banknotes while it does not pass fake banknotes.

With this technology we can detect and discriminate fake banknotes more precisely with compact construction at lower production cost.