Liquid-crystal display with reduced reflection

• US 4,529,272 A
• Filed: 09/08/1982
• Issued: 07/16/1985
• Est. Priority Date: 09/18/1981
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Leenhouts, Frans, Kruger, Hans
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): Lewis, David
• Application Number:
  US06/416,086
• Time in Patent Office: 1,042 Days
• Field of Search: 350/339 R, 350/341, 350/338, 350/166
• US Class Current: 349/137
• CPC Class Codes: G02F 1/133502 Antiglare, refractive index matching layers
• CPC Class Codes: G02F 1/1337 Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers

Abstract

A liquid crystal display with a liquid crystal layer enclosed by two parallel plates which carry electrodes and on top thereof a first layer system of several dielectric electrodes having refractive indices smaller than 2.2 and a thickness of the layers above the base layer, under 200 nm. The liquid crystal display is characterized by the following features with respect to the first carrier plate.

the electrode has a thickness d_e, within the range according to 0<d_e ≦30 nm or (mλ/2n_e -10) nm≦d_e ≦(mλ/2n_e +10) nm (λ=550 nm, m=natural integer>0, n_e =index of refraction of the electrode, nm=nanometer),

the base layer has an index of refraction n_b and a thickness d_b, within the range according to 1.40≦n_b ≦1.50 and 20 nm≦d_b ≦50 nm or (m 300/n_b -20) nm≦d_b ≦(m 300/n_b +20) nm,

the remaining layers of the first layer system have indices of refraction n_i and a total thickness d_s1-b according to 1.60≦n_i ≦1.70 and 20 nm≦d_s1-b <70 nm and

the orientation layer which is the uppermost layer of the first layer system aligns the adjacent liquid-crystal molecules.

Claims

1. A liquid-crystal display with

(1) a liquid-crystal layer enclosed by

(2) two mutually parallel spaced-apart carrier plates which

(3) carry electrically conductive coatings as electrodes on the surfaces of the two plates facing each other with at least one of the two carrier plates designated first carrier plate provided with

(4a) several separately addressable electrodes, and on top thereof

(4b) with a first layer system of several dielectric layers, the refraction indices of which have values smaller than 2.2 and the thicknesses of which are, at least in the case of the layers above the lowest layer designated base layer, under 200 nm,

the combination therewith wherein at least in the first carrier plate

(4c) the electrode has a thickness d_e, within the range according to 0<

d_e ≦

30 nm, wherein nm=nanometer,

(4d) the base layer has an index of refraction n_b and a thickness d_b, within the ranges according to 1.40≦

n_b ≦

1.50 and 20 nm≦

d_b ≦

50,

(4e) the remaining layers of the first layer system have indices of refraction n_i and a total thickness of d_sl-b according to 1.60≦

n_i ≦

1.70 and 20 nm≦

d_sl-b ≦

70 nm and

(4f) the orientation layer which is the uppermost layer of the first layer system aligns the adjacent liquid-crystal molecules.

5. A liquid-crystal display according to claim 1 or claim 2 or claim 3 or claim 4, wherein the carrier plate has an index of refraction n_t, according to 1.40≦

n_t ≦

1.60.

6. Liquid-crystal display according to claim 1 or claim 2 or claim 3 or claim 4, wherein the carrier plate has an index of refraction n_t, according to 1.40≦

n_t ≦

1.60, wherein the following indices and thicknesses are according to 1.40≦

n_t ≦

1.50;

1.95≦

n_e ≦

2.05;

25 nm≦

d_e ≦

30 nm;

1.44≦

n_b ≦

1.48;

28 nm≦

d_b ≦

45 nm; and

25 nm≦

d_sl-b ≦

40 nm.

7. A liquid-crystal display according to claim 1 or claim 2 or claim 3 or claim 4, wherein the carrier plate consists of glass, the conductive layer of an In₂ O₃ /Sn₂ O₂ alloy, the base layer of SiO₂ and the orientation layer of a polyimide wherein the carrier plate has an index of refraction n_t, according to 1.40≦

n_t ≦

1.60, wherein the following indices and thicknesses are according to 1.40≦

n_t ≦

1.50;

1.95≦

n_e ≦

2.05;

25 nm≦

d_e ≦

30 nm;

1.44≦

n_b ≦

1.48;

28 nm≦

d_b ≦

45 nm; and

25 nm≦

d_sl-b ≦

40 nm.

8. A liquid-crystal display according to claim 1 or claim 2 or claim 3 or claim 4, wherein a second system of dielectric layers is disposed between the first carrier plate and the separately addressable electrodes.

9. A liquid-crystal display according to claim 1 or claim 2 or claim 3 or claim 4, wherein a second system of dielectric layers is disposed between the first carrier plate and first layer system.

10. A liquid-crystal display according to claim 1 or claim 2 or claim 3 or claim 4, wherein a second system of dielectric layers is disposed between the first carrier plate and the separately addressable electrodes, wherein the carrier plate consists of a glass, the second layer system of a silicon dioxide layer, the electrode of an In₂ O₃ /SnO₂ alloy, the base layer of silicon dioxide, the orientation layer of a polyimide layer;

and a layer of aluminum oxide is further disposed between the base layer and the orientation layer.

11. A liquid-crystal display according to claim 1 or claim 2 or claim 3 or claim 4, wherein a second system of dielectric layers is disposed between the first carrier plate and first layer system, wherein the carrier plate consists of a glass, the second layer system of a silicon dioxide layer, the electrode of an In₂ O₃ /SnO₂ alloy, the base layer of silicon dioxide, the orientation layer of a polyimide layer;

and a layer of aluminum oxide is further disposed between the base layer and the orientation layer.

2. A liquid-crystal display with

(1) a liquid-crystal layer enclosed by

(2) two mutually parallel spaced-apart carrier plates which

(3) carry electrically conductive coatings as electrodes on the surfaces of the two plates facing each other with at least one of the two carrier plates designated first carrier plate provided with

(4a) several separately addressable electrodes, and on top thereof

(4b) with a first layer system of several dielectric layers, the refraction indices of which have values smaller than 2.2 and the thicknesses of which are, at least in the case of the layers above the lowest layer designated base layer, under 200 nm,

the combination therewith wherein at least in the first carrier plate

(4c) the electrode has a thickness d_e, within the range according to 0<

d_e ≦

30 nm, wherein nm=nanometer,

(4d) the base layer has an index of refraction n_b and a thickness d_b, within the ranges according to (m 300/n_b -20) nm≦

d_b ≦

(m 300/n_b +20)nm, wherein m=natural integer >

0,

(4e) the remaining layers of the first layer system have indices of refraction n_i and a total thickness d_sl-b according to 1.60≦

n_i ≦

1.70 and 20 nm≦

d_sl-b ≦

70 nm and

(4f) the orientation layer which is the uppermost layer of the first layer system aligns the adjacent liquid-crystal molecules.

3. A liquid-crystal display with

(1) a liquid-crystal layer enclosed by

(2) two mutually parallel spaced-apart carrier plates which

(3) carry electrically conductive coatings as electrodes on the surfaces of the two plates facing each other with at least one of the two carrier plates designated first carrier plate provided with

(4a) several separately addressable electrodes, and on top thereof

(4b) with a first layer system of several dielectric layers, the refraction indices of which have values smaller than 2.2 and the thicknesses of which are, at least in the case of the layers above the lowest layer designated base layer, under 200 nm,

the combination therewith wherein at least in the first carrier plate

(4c) the electrode has a thickness d_e, within the range according to

(m λ

/2n_e -10)nm≦

d_e ≦

(mλ

/2n_e +10)nm wherein λ

=550 nm, m=natural integer>

0, n_e =index of refraction of the electrode, and wherein nm=nanometer,

(4d) the base layer has an index of refraction n_b and a thickness d_b, within the ranges according to 1.40≦

n_b ≦

1.50 and 20 nm≦

d_b ≦

50,

(4e) the remaining layers of the first layer system have indices of refraction n_i and a total thickness d_sl-b according to 1.60≦

n_i ≦

1.70 and 20 nm≦

d_sl-b ≦

70 nm and

(4f) the orientation layer which is the uppermost layer of the first layer system aligns the adjacent liquid-crystal molecules.

4. A liquid-crystal display with

(1) a liquid-crystal layer enclosed by

(2) two mutually parallel spaced-apart carrier plates which

(3) carry electrically conductive coatings as electrodes on the surfaces of the two plates facing each other with at least one of the two carrier plates designated first carrier plate provided with

(4a) several separately addressable electrodes, and on top thereof

(4b) with a first layer system of several dielectric layers, the refraction indices of which have values smaller than 2.2 and the thicknesses of which are, at least in the case of the layers above the lowest layer designated base layer, under 200 nm,

the combination therewith wherein at least in the first carrier plate

(4c) the electrode has a thickness d_e, within the range according to (m λ

/2n_e -10)nm≦

d_e (m λ

/2n_e +10)nm wherein λ

=550 nm, m=natural integer>

0, n_e =index of refraction of the electrode, and wherein nm=nanometer,

(4d) the base layer has an index of refraction n_b and a thickness d_b, within the range according to (m 300/n_b -20)nm≦

d_b ≦

m 300/n_b +20)n_b wherein m=natural integer>

0,

(4e) the remaining layers of the first layer system have indices of refraction n_i and a total thickness d_sl-b according to 1.60≦

n_i ≦

1.70 and 20 nm≦

d_sl-b ≦

70 nm and

(4f) the orientation layer which is the uppermost layer of the first layer system aligns the adjacent liquid-crystal molecules.