DISPLAY DEVICE FOR CONTROLLING LIGHT TRANSMITTANCE

• US 20150168776A1
• Filed: 04/30/2014
• Published: 06/18/2015
• Est. Priority Date: 12/18/2013
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Song, Young-Woo, Yim, Sang-Hoon, Chung, Jin-Koo
• Granted Patent: US 9,391,127 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 2413/02 Number of plates being 2
• CPC Class Codes: G02F 2413/05 Single plate on one side of the LC cell
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/121 characterised by the geometry or disposition of pixel elements
• CPC Class Codes: H10K 59/50 OLEDs integrated with light modulating elements, e.g. with electrochromic elements, photochromic elements or liquid crystal elements
• CPC Class Codes: H10K 59/8791 Arrangements for improving contrast, e.g. preventing reflection of ambient light

Abstract

A display device that can control light transmittance is disclosed. One aspect is a display device for controlling light transmittance. The display device includes a light-emitting region and a light-transmitting region. The light-emitting region includes a light-emitting unit. The light-transmitting region includes a light-transmitting unit configured to adjust the transmittance of external light, wherein the light-emitting unit and the light-transmitting unit are formed over the same substrate.

Claims

1. A display device for controlling light transmittance, the display device comprising:

a transparent display, including;

a plurality of pixels each comprising a first region that includes an organic light-emitting diode (OLED); and

a second region configured to transmit external light,

wherein the OLED includes i) a first electrode formed in the first region of each pixel, ii) an organic layer comprising an organic emission layer, wherein the organic layer is formed over the first electrode, and iii) a second electrode substantially covering the organic layer and is electrically connected to the pixels;

a first polarizer formed over one side of an optical path of light emitted from the transparent display, wherein the first polarizer is configured to polarize and transmit external light; and

a second polarizer, formed over the opposite side of the optical path of the emitted light, wherein the second polarizer is configured to polarize the output of the first polarizer,

wherein the second region includes a liquid crystal device formed between the first and second polarizers,

wherein the combination of the first polarizer, the liquid crystal device and the second polarizer is configured to adjust the transmittance of external light through the transparent display.

2. The display device of claim 1, wherein the liquid crystal device comprises:

a third electrode formed in the second region of each pixel;

a liquid crystal layer formed over the third electrode, wherein the liquid crystal layer is not exposed to the environment; and

a fourth electrode substantially covering the liquid crystal layer and electrically connected to the pixels.

3. The display device of claim 2, further comprising:

a plurality of thin film transistors (TFTs) formed in the first region of each pixel;

at least one insulating layer substantially covering the TFTs; and

a transmission window formed in a portion of the at least one insulating layer corresponding to the second region, wherein the liquid crystal layer is formed in the transmission window.

4. The display device of claim 2, wherein the first electrode is a light-reflecting electrode, and wherein the third electrode is a light-transmitting electrode.

5. The display device of claim 1, wherein the first region comprises a circuit area including a thin film transistor (TFT), and an emission area including the first electrode, and wherein the circuit area and the emission area substantially overlap each other.

6. The display device of claim 4, wherein the fourth and second electrodes are integrally formed.

7. The display device of claim 2, wherein the first and third electrodes are light-transmitting electrodes.

8. The display device of claim 1, wherein the first region comprises a circuit area including a thin film transistor (TFT), and an emission area including the first electrode, and wherein the circuit area and the emission area are adjacent to each other.

9. The display device of claim 7, wherein the fourth and second electrodes are formed separately.

10. The display device of claim 2, wherein the liquid crystal device is formed separately for each pixel.

11. The display device of claim 2, wherein the liquid crystal device is electrically connected to at least two adjacent pixels.

12. The display device of claim 1, wherein vertical alignment nematic (VAN) liquid crystals are formed in the liquid crystal layer.

13. The display device of claim 1, wherein the transparent display device comprises:

a substrate on which the pixels are formed over a first surface thereof; and

an encapsulating substrate facing the first surface.

14. The display device of claim 13, wherein the encapsulating substrate is a thin film encapsulation (TFE) member.

15. The display device of claim 13, wherein the first polarizer comprises:

a first linear polarizer formed over the encapsulating substrate, wherein the first polarizer is configured to linearly polarize the external light and output a first linearly polarized light; and

a first retarder formed between the first linear polarizer and the encapsulating substrate, wherein the first retarder is configured to change a phase of the first linearly polarized light by a first phase and output a first retarded light,

wherein the second polarizer comprises;

a second linear polarizer formed below the substrate, wherein the second linear polarizer is configured to linearly polarize the first retarded light and output a second linearly polarized light; and

a second retarder formed between the second linear polarizer and the substrate wherein the second retarder is configured to change the phase of the second linearly polarized light by a second phase, and

wherein the first and second phases have substantially the same absolute value but different rotation directions.