Liquid crystal display device with light transmission and reflection regions

• US 6,819,379 B2
• Filed: 08/13/2001
• Issued: 11/16/2004
• Est. Priority Date: 12/26/1997
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Shimada, Takayuki, Kubo, Masumi, Ishii, Yutaka, Ban, Atsushi, Yoshimura, Youji, Narutaki, Yozo, Maruyama, Yuko, Yamakawa, Shinya, Katayama, Mikio, Fujioka, Shogo
• Primary Examiner(s): CHOWDHURY, TARIFUR RASHID
• Application Number:
  US09/927,547
• Publication Number:
  US 20010055082A1
• Time in Patent Office: 1,191 Days
• Field of Search: 349/84, 349/96, 349/113, 349/114, 349/117, 349/119, 349/147, 349/138, 349/143, 349/144, 257/59, 257/72
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133371 Cells with varying thickness of the liquid crystal layer
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/133557 Half-mirrors
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/1362 Active matrix addressed cells G02F1/134336, G02F1/134363 take precedence
• CPC Class Codes: G02F 1/13712 the liquid crystal having negative dielectric anisotropy
• CPC Class Codes: G02F 2203/09 transflective

Abstract

A liquid crystal display device includes a first substrate; a second substrate; a liquid crystal layer interposed between the first substrate and the second substrate; a first polarizer provided on a surface of the first substrate which is on the opposite side to the liquid crystal layer; a second polarizer provided on a surface of the second substrate which is on the opposite side to the liquid crystal layer; a first phase compensation element provided between the first polarizer and the liquid crystal layer; and a second phase compensation element provided between the second polarizer and the liquid crystal layer. A plurality of pixel areas are provided for display. The first substrate includes at least one transmissive electrode, and the second substrate includes a reflective electrode region and a transmissive electrode region in correspondence with each of the plurality of pixel areas.

Claims

1. A liquid crystal display device comprising:

a first substrate and a second substrate;

a liquid crystal layer interposed between the first substrate and the second substrate;

a first polarizer provided on a surface of the first substrate which is opposite the liquid crystal layer;

a second polarizer provided on a surface of the second substrate which is opposite the liquid crystal layer;

a first phase compensation element provided between the first polarizer and the liquid crystal layer; and

a second phase compensation element provided between the second polarizer and the liquid crystal layer,

wherein a plurality of pixel areas are provided for display, each of the plurality of pixel areas is a liquid crystal region including a reflection area for performing display using reflected light and a transmission area for performing display using transmitted light, wherein a reflective electrode region defining the reflection area and a transmissive electrode region defining the transmission area are formed in correspondence with each pixel area on the second substrate, and

wherein a thickness (d1) of the liquid crystal layer in the transmissive electrode region and a thickness (d2) of the liquid crystal layer in the reflective electrode region are defined by a relationship d1>

d2, and wherein thickness d1 is substantially larger than thickness d2 so that electrooptical characteristics of the reflection area and the transmission area are approximately matched.

2. A liquid crystal display device comprising:

a first substrate and a second substrate;

a liquid crystal layer interposed between the first substrate and the second substrate;

a first polarizer provided on a surface of the first substrate which is opposite the liquid crystal layer;

a second polarizer provided on a surface of the second substrate which is opposite the liquid crystal layer;

a first phase compensation element provided between the first polarizer and the liquid crystal layer; and

a second phase compensation element provided between the second polarizer and the liquid crystal layer,

wherein a plurality of pixel areas are provided for display, each of the plurality of pixel areas comprises a reflection area for performing display using reflected light and a transmission area for performing display using transmitted light, wherein a reflective electrode region defining the reflection area and a trasmissive electrode region defining the transmission area are formed in correspondence with each pixel area on the second substrate,

wherein a thickness (d1) of the liquid crystal Layer in the transmissive electrode region and a thickness (d2) of the liquid crystal layer in the reflective electrode region are defined by a relationship d1>

2×

d2.

3. A liquid crystal display device comprising:

a first substrate and a second substrate;

a liquid crystal layer interposed between at least the first substrate and the second substrate;

a first polarizer supported by the first substrate;

a second polarizer supported by the second substrate;

wherein a plurality of pixel areas are provided for display, at least one of the pixel areas comprising a liquid crystal region including a reflection area for performing display using reflected light and a transmission area for performing display using transmitted light, wherein a reflective electrode is provided in at least the reflection area and a transmissive electrode is provided in at least the transmission area, said reflective and transmissive electrodes each being supported by the second substrate; and

wherein a thickness (d1) of the liquid crystal layer in the transmissive area and a thickness (d2) of the liquid crystal layer in the reflection urea are defined by a relationship d1>

d2, and wherein thickness d1 substantially larger than thickness d2.

4. The liquid crystal display device of claim 3, wherein the reflective electrode is located over top of the transmissive electrode.

5. The liquid crystal display device of claim 3, wherein d1≧

d2.

6. The liquid crystal display device of claim 3, wherein at least part of the reflective electrode overlaps part of the transmissive electrode.

7. The liquid crystal display device of claim 3, further comprising an optical compensating film located on each side of the liquid crystal layer.

8. The liquid crystal display device of claim 3, wherein d1≧

d2×

2.

9. The liquid crystal display device of claim 3, wherein at least parts of both the reflective and transmissive electrodes are located in the reflection area.

10. The liquid crystal display device of claim 9, wherein the transmission area comprises the transmissive electrode but not the reflective electrode.

11. The liquid crystal display device of claim 3, wherein the reflective and transmissive electrodes are both supported by the second substrate, wherein color filters of the display are supported by the first substrate and are thus across the liquid crystal layer from the transmissive and reflective electrodes.

12. A liquid crystal display device comprising:

a first substrate and a second substrate;

a liquid crystal layer interposed between at least the first substrate and the second substrate;

wherein a plurality of pixel areas are provided for display, at least one of the pixel areas comprising a liquid crystal region including a reflection area for performing display using reflected light and a transmission area for performing display using transmitted light, wherein a reflective electrode is provided in at least the reflection area and a transmissive electrode is provided in at least the transmission area, said reflective and transmissive electrodes each being supported by the second substrate; and

wherein a thickness (d1) of the liquid crystal layer in the transmissive area and a thickness (d2) of the liquid crystal layer in the reflection area are defined by a relationship d1≧

d2×

2.

13. The liquid crystal display device of claim 12, wherein the reflective electrode is located over top of the transmissive electrode.

14. The liquid crystal display device of claim 12, wherein at least part of the reflective electrode overlaps part of the transmissive electrode.

15. The liquid crystal display device of claim 12, further comprising an optical compensating film located on each side of the liquid crystal layer.

16. The liquid crystal display device of claim 12, wherein at least parts of both the reflective and transmissive electrodes are located in the reflection area.

17. The liquid crystal display device of claim 16, wherein the transmission area comprises the transmissive electrode but not the reflective electrode.

18. A liquid crystal display device comprising:

a first substrate and a second substrate;

a liquid crystal layer interposed between at least the first substrate and the second substrate;

wherein at least one pixel area comprises a liquid crystal region including a reflection area for performing display using reflected light and a transmission area for performing display using transmitted light, wherein a reflective electrode is provided in at least the reflection area and a transmissive electrode is provided in at least the transmission area, maid reflective and transmissive electrodes each being supported by the second substrate;

wherein a thickness (d1) of the liquid crystal layer in the transmissive area and a thickness (d2) of the liquid crystal layer in the reflection area are defined by a relationship d1>

d2, and wherein thickness d1 is substantially larger ban thickness d2, and wherein the reflective electrode at least partially overlaps the transmissive electrode.

19. A liquid crystal display device comprising a first substrate, a second substrate, and a liquid crystal layer provided between at least the first and second substrates, a plurality of pixel regions comprising respective electrodes for applying voltage to the liquid crystal layer,

wherein each of a plurality of the pixel regions includes a reflection region and a transmission region, and wherein light reflected in said reflection regions and light transmitted through said transmission regions are utilized in displaying an image;

wherein the first substrate includes a reflection electrode region provided in at least the reflection region of a pixel region and a transmission electrode region provided in at least the transmission region of the pixel region; and

wherein the reflection electrode region is higher than the transmission electrode region, forming a step on a surface of the first substrate, and thus a thickness of the liquid crystal layer in the reflection region is smaller than a thickness of the liquid crystal layer in the transmission region.