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Fingerprint Sensor
LES (Light Emitting Sensor)Dual SensorOptical SensorFingerprint sensor selection


LES (Light Emitting Sensor)
LE센서
It is a Polymer based sensor that emits light when fingerprint is contacted.

It is designed for demanding environments where users are exposed to bright sunlight, dusty, dirty and dry conditions.
There is also a function of fake fingerprint detection technology.
Sensor block diagram
What is light emitting sensor?
It is polymer based sensor that emits light through the rifges of the finger when a live finger is contacted.

Emitting theory
There are many luminescent centers in the luminescent layer. (Picture below)
- Electric field is generated if a finger is contacted.
- Electrons on trap level in the luminescent layer will gain the energy.
- These electrons repeats togo to ground state and go to excited
   state continuously and it makes lights.

Light emitting sensor structure
It is polymer based sensor that emits light through the ridges of the finger when a live finger is contacted.



Repellent layer technology
1. We developed the polymer that has the characteristics of chemical resistance, abrasion resistance, heat resistence, repellent.

2. Repellent layer development
   - Generally, the manufacturing process of polymer that has the characteristics of chemical resistance, abrasion resistance, heat resistance is done at
   high remperature, and it is difficult to apply.
   - We develloped low temperature (below 100℃) process to apply easier.

3. Repellent layer efficiency : refer to pictures below

Good repellent :
Good for wet fingers



(No repellent layer)


(Add repellent layer)
Abrasion resistance : Life time
(more than 1,500,000 touches)



(Initial image)


(After 1,500,000 touches)

[LE sensor's repellent and abrasion resistance characteristics]
Life time
Generally, competitors announced their touching life time is about 1,500,000 touches.
We referred this and tested, but there is no problem if it is higher than 1,500,000 touches.

1. Mechanical Life time test
  (Method)
  - We made the automatic tester below and tested.
  - We tested until 1,500,000 touches.
  (Result)
  - We tested with cow skin and so the real life time si longer than the result.

Make a fake fingerprint using adhesive
Very easy
Hacking comparison optical & out Le sensor
1. Optical fingerprint reader
2. LE fingerprint reader
Compare SENSOR - 1

Compare SENSOR - 2

Works well in harsh environments including direct sunlight.

Because direct sunlight cannot penetrate the surface of the LE sensor
Works poorly in harsh environments including direct sunlight.

Because direct sunlight can penetrate the surface of the optical sensor
Simulation Test (Direct sun light)
Please see attached movie