Display device

• US 9,164,313 B2
• Filed: 11/09/2010
• Issued: 10/20/2015
• Est. Priority Date: 01/31/2006
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Egi, Yuji, Ishitani, Tetsuji, Nishi, Takeshi
• Primary Examiner(s): Nguyen, Lauren
• Assistant Examiner(s): Quash, Anthony G
• Application Number:
  US12/942,061
• Publication Number:
  US 20110051034A1
• Time in Patent Office: 1,806 Days
• Field of Search: 359/437, 349/96, 349/437
• US Class Current: 1/1
• CPC Class Codes: G02F 1/133531 characterised by the arrangement of polariser or analyser axes
• CPC Class Codes: G02F 1/133533 Colour selective polarisers G02F1/1347 takes precedence
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 2203/04 wavelength independent
• CPC Class Codes: G02F 2203/64 Normally black display, i.e. the off state being black

Abstract

To provide a display device having a high contrast ratio by a simple and easy method and to manufacture a high-performance display device at low cost, in a display device having a display element between a pair of light-transmitting substrates, layers each including a polarizer having different wavelength distribution of extinction coefficient from each other with respect to the absorption axes are stacked and provided on an outer side of the light-transmitting substrates. Further, a retardation plate may be provided between the stacked polarizers.

Claims

1. A display device comprising:

a first light-transmitting substrate and a second light-transmitting substrate which are disposed to face each other;

a display element sandwiched between the first light-transmitting substrate and the second light-transmitting substrate; and

a layer including a first polarizer, a second polarizer, a third polarizer provided between a viewer and the first light-transmitting substrate,

wherein the first polarizer and the second polarizer are arranged so that their absorption axes are in a parallel Nicols state,

wherein the third polarizer is arranged so that an absorption axis of the third polarizer is deviated from the parallel Nicols state,

wherein the second polarizer and the third polarizer are not arranged so that their absorption axes are in a cross Nicols state,

wherein the first polarizer, the second polarizer, and the third polarizer are sequentially stacked from the first light-transmitting substrate,

wherein the second polarizer is in direct contact with the third polarizer.

2. The display device according to claim 1, wherein the display element is a liquid crystal element.

3. The display device according to claim 1, further comprising:

a light source on an outer side of the second light-transmitting substrate.

4. The display device according to claim 3, wherein the light source is light emitting diode (LED).

5. The display device according to claim 4, wherein the light emitting diode (LED) is configured to be driven by a successive additive color mixture method (a filed sequential method).

6. The display device according to claim 1, wherein the display device is one selected the group consisting of a television device, a digital camera, a digital video camera, a mobile phone, a portable information terminal (PDA), a portable game machine, a monitor for computer, and an image reproducing device.

7. A display device comprising:

a first light-transmitting substrate and a second light-transmitting substrate which are disposed to face each other;

a display element sandwiched between the first light-transmitting substrate and the second light-transmitting substrate;

a first layer including a first polarizer, a second polarizer, a third polarizer provided between a viewer and the first light-transmitting substrate; and

a second layer including a fourth polarizer and a fifth polarizer on an outer side of the second light-transmitting substrate,

wherein the first polarizer and the second polarizer are arranged so that their absorption axes are in a parallel Nicols state,

wherein the third polarizer is arranged so that an absorption axis of the third polarizer is deviated from the parallel Nicols state,

wherein the second polarizer and the third polarizer are not arranged so that their absorption axes are in a cross Nicols state,

wherein the fourth polarizer and the fifth polarizer are arranged so that their absorption axes are in a parallel Nicols state,

wherein the first polarizer, the second polarizer, and the third polarizer are sequentially stacked from the first light-transmitting substrate, and

wherein the second polarizer is in direct contact with the third polarizer.

8. The display device according to claim 7, wherein the display element is a liquid crystal element.

9. The display device according to claim 7, further comprising:

a light source on an outer side of the second layer.

10. The display device according to claim 9, wherein the light source is light emitting diode (LED).

11. The display device according to claim 10, wherein the light emitting diode (LED) is configured to be driven by a successive additive color mixture method (a filed sequential method).

12. The display device according to claim 7, wherein the display device is one selected the group consisting of a television device, a digital camera, a digital video camera, a mobile phone, a portable information terminal (PDA), a portable game machine, a monitor for computer, and an image reproducing device.

13. A display device comprising:

a first light-transmitting substrate and a second light-transmitting substrate which are disposed to face each other;

a display element sandwiched between the first light-transmitting substrate and the second light-transmitting substrate;

a first layer including a first polarizer, a second polarizer, a third polarizer provided between a viewer and the first light-transmitting substrate; and

a second layer including a fourth polarizer and a fifth polarizer on an outer side of the second light-transmitting substrate,

wherein the first polarizer and the second polarizer are arranged so that their absorption axes are in a parallel Nicols state,

wherein the third polarizer is arranged so that an absorption axis of the third polarizer is deviated from the parallel Nicols state,

wherein the second polarizer and the third polarizer are not arranged so that their absorption axes are in a cross Nicols state,

wherein the fourth polarizer and the fifth polarizer are arranged to so that their absorption axes are in a parallel Nicols state,

wherein the first polarizer, the second polarizer, and the third polarizer are sequentially stacked from the first light-transmitting substrate,

wherein the second polarizer and the forth polarizer are arranged so that their absorption axes are a crossed Nicols state, and

wherein the second polarizer is in direct contact with the third polarizer.

14. The display device according to claim 13, wherein the display element is a liquid crystal element.

15. The display device according to claim 13, further comprising:

a light source on an outer side of the second layer.

16. The display device according to claim 15, wherein the light source is light emitting diode (LED).

17. The display device according to claim 16, wherein the light emitting diode (LED) is configured to be driven by a successive additive color mixture method (a filed sequential method).

18. The display device according to claim 13, wherein the display device is one selected the group consisting of a television device, a digital camera, digital video camera, a mobile phone, a portable information terminal (PDA), a portable game machine, a monitor for computer, and an image reproducing device.