Fingerprint recognition sensor and portable display device having the same

• US 10,078,777 B2
• Filed: 01/10/2017
• Issued: 09/18/2018
• Est. Priority Date: 08/29/2016
• Status: Active Grant

• Current Assignee: Silicon Display Technology
• Original Assignee: Silicon Display Technology
• Inventors: Kim, Jaemin, Kim, Kijoong, Park, Young Man, Hur, Ji Ho
• Primary Examiner(s): Shah, Utpal
• Application Number:
  US15/402,388
• Publication Number:
  US 20180060642A1
• Time in Patent Office: 616 Days
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G06V 40/1318 using electro-optical elements or layers, e.g. electroluminescent sensing
• CPC Class Codes: G06V 40/1324 by using geometrical optics, e.g. using prisms G06V40/1312 takes precedence
• CPC Class Codes: G06V 40/1329 Protecting the fingerprint sensor against damage caused by the finger
• CPC Class Codes: G06V 40/1365 Matching; Classification

Abstract

Disclosed are a fingerprint recognition sensor including: a light source positioned while being spaced apart on one surface of the substrate and irradiating light toward the substrate; and a light direction switching layer positioned between the substrate and the light source, having a thickness-direction cross-section having a right-angled triangular shape, and including multiple protrusions constituted by a first surface in which the light irradiated from the light source is incident and refracted, a second surface contacting the one surface of the substrate, in which the refracted light is transmitted toward the substrate, and a third surface vertical to the one surface of the substrate, and a mobile display device having the same.

Claims

1. A fingerprint recognition sensor comprising:

a light source positioned while being spaced apart on one surface of the substrate and irradiating light toward the substrate;

a light direction switching layer positioned between the substrate and the light source, having a thickness-direction cross-section having a right-angled triangular shape, and including multiple protrusions constituted by a first surface in which the light irradiated from the light source is incident and refracted, a second surface contacting the one surface of the substrate, in which the refracted light is transmitted toward the substrate, and a third surface vertical to the one surface of the substrate;

a cover layer spaced apart from the other surface of the substrate and facing the substrate;

multiple sensor pixels defined by multiple scan lines and multiple data readout lines on the other surface of the substrate and positioned between the substrate and the cover layer; and

multiple photo sensors positioned in the respective sensor pixels and sensing the light transmitted from the light direction switching layer toward the substrate and total-reflected on a surface contacting a fingerprint of a user on the cover layer,

wherein an angle formed by the first surface and the third surface of the protrusion is 19°

or lower.

2. The fingerprint recognition sensor of claim 1, wherein:

as the angle formed by the first surface and the third surface of the protrusion is smaller, an incident angle of the light transmitted toward the substrate on the surface contacting the fingerprint of the user in the cover layer increases.

3. The fingerprint recognition sensor of claim 1, wherein:

the angle formed by the first surface and the third surface of the respective protrusion is different from each other.

4. The fingerprint recognition sensor of claim 3, wherein:

a thickness-direction length of the third surface of the respective protrusion is different from each other.

5. The fingerprint recognition sensor of claim 1, wherein:

a refractive index of the respective protrusion is larger than 1.0 and equal to or less than 2.0, and

the refractive index of the respective protrusion is the same as each other.

6. The fingerprint recognition sensor of claim 5, wherein:

the refractive index of the cover layer is larger than 1.0 and equal to or less than 2.0, and

the refractive index of the cover layer is the same as the refractive index of the protrusion.

7. The fingerprint recognition sensor of claim 1, further comprising:

multiple thin film transistors connected to the multiple scan lines and the multiple data readout lines and transmitting a current signal depending on resistance variation of each photo sensor to the multiple data readout lines,

wherein each photo sensor includes a first electrode formed by extending the drain electrode of the thin film transistor, a semiconductor layer positioned on the first electrode, and a second electrode including the transparent material and positioned on the semiconductor layer, and

wherein the first electrode and the second electrode form a capacitor.

8. The fingerprint recognition sensor of claim 7, wherein:

the thin film transistor has a co-planar structure, a staggered structure, an inverted co-planar structure, or an inverted staggered structure.

9. The fingerprint recognition sensor of claim 7, wherein:

a channel layer of the thin film transistor includes a low-temperature polycrystalline silicon (LTPS), an amorphous silicon (a-Si), or an oxide.

10. The fingerprint recognition sensor of claim 7, wherein:

a semiconductor layer of the photo sensor includes an amorphous silicon (a-Si), an organic material, or a quantum dot.

16. A mobile display device comprising:

a display panel displaying an image or video;

a transparent protective layer positioned on the display panel; and

a fingerprint recognition sensor of claim 1, which is positioned at least at a partial area between the display panel and the transparent protective layer.

17. The mobile display device of claim 16, wherein:

the fingerprint recognition sensor is positioned at a groove positioned in a partial area of the transparent protective layer.

11. A fingerprint recognition sensor comprising:

a light source positioned while being spaced apart on one surface of the substrate and irradiating light toward the substrate;

a first light direction switching layer positioned between the substrate and the light source, having a thickness-direction cross-section having a right-angled triangular shape, and including multiple first protrusions constituted by a first surface in which the light irradiated from the light source is incident and refracted, a second surface parallel to the one surface of the substrate, in which the refracted light is transmitted, and a third surface vertical to the one surface of the substrate;

a second light direction switching layer positioned between the first light direction switching layer and the substrate and having a thickness-direction cross-section having a right-angled triangular shape, and including multiple second protrusions constituted by a fourth surface in which the light transmitted from the first light direction switching layer is incident and refracted, a fifth surface contacting the one surface of the substrate, in which the refracted light is transmitted toward the substrate, and a sixth surface vertical to the one surface of the substrate;

a cover layer spaced apart from the other surface of the substrate and facing the substrate;

multiple sensor pixels defined by multiple scan lines and multiple data readout lines on the other surface of the substrate and positioned between the substrate and the cover layer; and

multiple photo sensors positioned in the respective sensor pixels and sensing the light transmitted from the second light direction switching layer toward the substrate and total-reflected on a surface contacting a fingerprint of a user on the cover layer.

12. The fingerprint recognition sensor of claim 11, wherein:

the angle formed by the first surface and the third surface of the respective first protrusion is different from each other, and

a thickness-direction length of the third surface of the respective first protrusion is the same as each other.

13. The fingerprint recognition sensor of claim 12, wherein:

the respective first protrusion and the respective second protrusion overlap with each other in the thickness direction, and

the angle formed by the first surface and the third surface of the respective first protrusion is the same as the angle formed by the fourth surface and the sixth surface of the respective second protrusion which overlaps with the respective first protrusion.

14. The fingerprint recognition sensor of claim 11, wherein:

a refractive index of the first protrusion is different from a refractive index of the second protrusion.

15. The fingerprint recognition sensor of claim 11, further comprising:

multiple thin film transistors connected to the multiple scan lines and the multiple data readout lines and transmitting a current signal depending on resistance variation of each photo sensor to the multiple data readout lines.