Liquid crystal display device and electronic apparatus

• US 20040061812A1
• Filed: 07/09/2003
• Published: 04/01/2004
• Est. Priority Date: 07/22/2002
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Maeda, Tsuyoshi
• Granted Patent: US 7,106,395 B2
• Time in Patent Office: Days
• US Class Current: 349/65
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

The invention provides a liquid crystal display device having a high display luminance and performs highly visibly display even in a bright outdoor environment. The invention also provides an electronic apparatus equipped with the same. A liquid crystal display device according to the present invention includes (i) a liquid crystal display panel having: a upper substrate and a lower substrate which are disposed so as to oppose each other; a liquid crystal layer sandwiched by the two substrates; an upper polarizer and a lower polarizer disposed above and below the liquid crystal layer, and (ii) a backlight (illumination device) disposed close to the rear surface of the liquid crystal display panel. The backlight includes a prism sheet which has a prism surface having a plurality of ribs, each having an approximately triangular cross-section, formed thereon close to the liquid crystal display panel, and which is arranged such that the prism surface faces in the opposite direction to the liquid crystal display panel. Also, the lower polarizer has a light diffusing layer and a reflective polarizer deposited in that order on the outer surface thereof.

Claims

1. A liquid crystal display device, comprising:

a liquid crystal display panel that includes;

an upper substrate and a lower substrate disposed so as to oppose each other;

a liquid crystal layer sandwiched between the two substrates; and

an upper polarizer and a lower polarizer respectively disposed above and below the liquid crystal layer; and

an illumination device disposed close to a rear surface of the liquid crystal display panel, the illumination device including a prism sheet which has a prism surface having a plurality of ribs, each having an approximately triangular cross-section, formed thereon close to the liquid crystal display panel, and which is arranged such that the prism surface faces in the opposite direction to the liquid crystal display panel, and

the lower polarizer having a light diffusing layer and a reflective polarizer deposited in that order on an outer surface of the lower polarizer.

2. The liquid crystal display device according to claim 1, each of the ribs of the prism sheet having an apex in a range from 63 degrees to 68 degrees.

3. The liquid crystal display device according to claim 1, the liquid crystal layer including TN (twisted nematic) liquid crystal, and

the liquid crystal display panel having a clear viewing direction in a direction of about six o'"'"'clock.

4. The liquid crystal display device according to claim 1, the ribs of the prism sheet extending in a direction substantially orthogonal to an incident direction of external light in use.

5. The liquid crystal display device according to claim 1, the illumination device including a light source and a light-guiding plate, and the light source being disposed on an end surface of the light-guiding plate, the end surface extending orthogonal to the width direction of the ribs of the prism sheet.

6. The liquid crystal display device according to claim 1, the transmissive polarization axes of the lower polarizer and the reflective polarizer being arranged so as to be substantially parallel to each other.

7. The liquid crystal display device according to claim 6, the transmissive polarization axes of the lower polarizer and the reflective polarizer being arranged so as to form an angle in a range from −

30 degrees to 30 degrees.

8. The liquid crystal display device according to claim 1, the light diffusing layer having a haze value in a range from 60% to 85%.

9. An electronic apparatus, comprising:

the liquid crystal device according to claim 1.