Spread illuminating apparatus to illuminate two liquid crystal display panels different in screen size

• US 7,248,308 B2
• Filed: 12/04/2003
• Issued: 07/24/2007
• Est. Priority Date: 01/24/2003
• Status: Expired due to Fees

• Current Assignee: Minebea Company Limited (MinebeaMitsumi Inc.)
• Original Assignee: Minebea Company Limited (MinebeaMitsumi Inc.)
• Inventors: Kawashima, Satoshi, Mizutani, Hitoshi, Egawa, Motoji, Ishigami, Katsuji, Takayanagi, Kazutoshi
• Primary Examiner(s): Nguyen; Dung T.
• Assistant Examiner(s): Duong; Thoi V.
• Application Number:
  US10/726,682
• Publication Number:
  US 20040145688A1
• Time in Patent Office: 1,328 Days
• Field of Search: 349/65, 349/67, 349/73, 349/96, 349113-115, 349/63, 349/61, 349/62, 349/74, 349/69, 349/70, 362/560, 362/561, 362/603, 362/604, 362/623, 362/625, 362/626, 362/602, 362/609, 362/611, 362/615
• US Class Current: 349/67
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02B 6/0063 for extracting light out both the major surfaces of the light guide
• CPC Class Codes: G02F 1/133342 for double-sided displays

Abstract

A spread illuminating apparatus includes: at least one light source; a light conductive plate which has the at least one light source disposed at one end surface thereof, and which allows light emitted from the at least one light source and introduced therein to exit out therefrom through both major surfaces thereof toward first and second liquid crystal display elements disposed respectively over the both major surfaces of the light conductive plate, wherein the second liquid crystal display element has a smaller display screen size than the first liquid crystal display element; and a reflecting means which is disposed at the other major surface of the light conductive plate so as to cover at least areas not covered by the second liquid crystal display element, and which reflects light toward the first liquid crystal display element.

Claims

1. A spread illuminating apparatus for illuminating two objects, the apparatus comprising:

at least one light source;

a light conductive plate having the at least one light source provided at one end surface thereof and adapted to allow light emitted from the at least one light source and introduced therein to exit out therefrom through two major surfaces thereof respectively toward a first liquid crystal display element which constitutes one of two objects to be illuminated, and which is disposed over one of the two major surfaces of the light conductive plate, and toward a second liquid crystal display element which constitutes the other of the two objects to be illuminated, has a smaller display screen size than the first liquid crystal display element, and which is partially disposed over the other of the two major surfaces of the light conductive plate, the second liquid crystal display element covering one area, but not covering another area, of the other of the two major surfaces of the light conductive plate; and

a reflector plate, reflecting light toward the first liquid crystal display element, partially disposed at the other major surface of the light conductive plate having the second liquid crystal display element, the reflector plate covering an area of the other of the two major surfaces that is not covered by the second liquid crystal display element, the reflector plate not covering an area of the other of the two major surfaces that is covered by the second liquid crystal display element,

wherein the reflector plate has a reflectance that matches with a reflectance of the second liquid crystal display element.

2. A spread illuminating apparatus according to claim 1 wherein the reflector plate has an area partially formed thereon so that the reflectance of the reflector plate gradually decreases according to a distance from the second liquid crystal display element.

3. A spread illuminating apparatus according to claim 1 wherein the reflector plate has its reflectance gradually varying at a given area close to the second liquid crystal display element.

4. A spread illuminating apparatus for illuminating two objects, the apparatus comprising:

at least one light source;

a light conductive plate having the at least one light source provided at one end surface thereof and adapted to allow light emitted from the at least one light source and introduced therein to exit out therefrom through two major surfaces thereof respectively toward a first liquid crystal display element which constitutes one of two objects to be illuminated, and which is disposed over one of the two major surfaces of the light conductive plate, and toward a second liquid crystal display element which constitutes the other of the two objects to be illuminated, has a smaller display screen size than the first liquid crystal display element, and which is partially disposed over the other of the two major surfaces of the light conductive plate, the second liquid crystal display element covering one area, but not covering another area, of the other of the two major surfaces of the light conductive plate; and

a reflector plate partially provided so as to cover an area of the other of the two major surfaces that is not covered by the second liquid crystal display element, the reflector plate not covering an area of the other of the two major surfaces that is covered by the second liquid crystal display element; and

a reflective polarizer plate which reflects P-polarized light and transmits S-polarized light selectively, or vice versa, and which is provided so as to cover entirely the other major surface of the light conductive plate having the second liquid crystal display element,

wherein the reflector plate has a reflectance that matches with a reflectance of the second liquid crystal display element.

5. A spread illuminating apparatus according to claim 4 wherein the reflector plate has an area partially formed thereon so that the reflectance of the reflector plate gradually decreases according to a distance from the second liquid crystal display element.

6. A spread illuminating apparatus for illuminating two objects, the apparatus comprising:

at least one light source;

a light conductive plate having the at least one light source provided at one end surface thereof and adapted to allow light emitted from the at least one light source and introduced therein to exit out therefrom through two major surfaces thereof respectively toward a first liquid crystal display element which constitutes one of two objects to be illuminated, and which is disposed over one of the two major surfaces of the light conductive plate, and toward a second liquid crystal display element which constitutes the other of the two objects to be illuminated, has a smaller display screen size than the first liquid crystal display element, and which is partially disposed over the other of the two major surfaces of the light conductive plate, the second liquid crystal display element covering one area, but not covering another area, of the other of the two major surfaces of the light conductive plate; and

a reflector plate partially provided so as to cover an area of the other of the two major surfaces that is not covered by the second liquid crystal display element, the reflector plate not covering an area of the other of the two major surfaces that is covered by the second liquid crystal display element, and

a reflective polarizer plate which reflects P-polarized light and transmits S-polarized light selectively, or vice versa, and which is provided entirely at and in direct contact with the other major surface of the light conductive plate having the second liquid crystal display element,

wherein the reflector plate has a reflectance that matches with a reflectance of the second liquid crystal display element.

7. A spread illuminating apparatus according to claim 6 wherein the reflector plate has an area partially formed thereon so that the reflectance of the reflector plate gradually decreases according to a distance from the second liquid crystal display element.

8. A spread illuminating apparatus for illuminating two objects, the apparatus comprising:

at least one light source;

a light conductive plate having the at least one light source provided at one end surface thereof and adapted to allow light emitted from the at least one light source and introduced therein to exit out therefrom through two major surfaces thereof respectively toward a first liquid crystal display element which constitutes one of two objects to be illuminated, and which is disposed over one of the two major surfaces of the light conductive plate, and toward a second liquid crystal display element which constitutes the other of the two objects to be illuminated, has a smaller display screen size than the first liquid crystal display element, and which is partially disposed over the other of the two major surfaces of the light conductive plate, the second liquid crystal display element covering one area, but not covering another area, of the other of the two major surfaces of the light conductive plate; and

a reflector plate, reflecting light toward the first liquid crystal display element, partially disposed at the other major surface of the light conductive plate having the second liquid crystal display element, the reflector plate covering an area of the other of the two major surfaces that is not covered by the second liquid crystal display element, the reflector plate not covering an area of the other of the two major surfaces that is covered by the second liquid crystal display element,

wherein the reflector plate has an area facing the light conductive plate and only partially formed at an end area close to a boundary formed between the second liquid crystal display element and the reflector plate, so that the reflectance of the reflector plate gradually decreases according to a distance from the second liquid crystal display element in the area, and

wherein the area partially formed on the reflector plate is provided without overlapping any parts of the second liquid crystal display element relative to a back surface of the light conductive plate.

9. A spread illuminating apparatus for illuminating two objects, the apparatus comprising:

at least one light source;

a light conductive plate having the at least one light source provided at one end surface thereof and adapted to allow light emitted from the at least one light source and introduced therein to exit out therefrom through two major surfaces thereof respectively toward a first liquid crystal display element which constitutes one of two objects to be illuminated, and which is disposed over one of the two major surfaces of the light conductive plate, and toward a second liquid crystal display element which constitutes the other of the two objects to be illuminated, has a smaller display screen size than the first liquid crystal display element, and which is partially disposed over the other of the two major surfaces of the light conductive plate, the second liquid crystal display element covering one area, but not covering another area, of the other of the two major surfaces of the light conductive plate; and

a reflector plate partially provided so as to cover an area of the other of the two major surfaces that is not covered by the second liquid crystal display element, the reflector plate not covering an area of the other of the two major surfaces that is covered by the second liquid crystal display element; and

a reflective polarizer plate which reflects P-polarized light and transmits S-polarized light selectively, or vice versa, and which is provided so as to cover entirely the other major surface of the light conductive plate having the second liquid crystal display element,

wherein the reflector plate has an area facing the light conductive plate and only partially formed at an end area close to a boundary formed between the second liquid crystal display element and the reflector plate, so that the reflectance of the reflector plate gradually decreases according to a distance from the second liquid crystal display element in the area, and

wherein the area partially formed on the reflector plate is provided without overlapping any parts of the second liquid crystal display element relative to a back surface of the light conductive plate.

10. A spread illuminating apparatus for illuminating two objects, the apparatus comprising:

at least one light source;

a light conductive plate having the at least one light source provided at one end surface thereof and adapted to allow light emitted from the at least one light source and introduced therein to exit out therefrom through two major surfaces thereof respectively toward a first liquid crystal display element which constitutes one of two objects to be illuminated, and which is disposed over one of the two major surfaces of the light conductive plate, and toward a second liquid crystal display element which constitutes the other of the two objects to be illuminated, has a smaller display screen size than the first liquid crystal display element, and which is partially disposed over the other of the two major surfaces of the light conductive plate, the second liquid crystal display element covering one area, but not covering another area, of the other of the two major surfaces of the light conductive plate; and

a reflector plate partially provided so as to cover an area of the other of the two major surfaces that is not covered by the second liquid crystal display element, the reflector plate not covering an area of the other of the two major surfaces that is covered by the second liquid crystal display element, and

a reflective polarizer plate which reflects P-polarized light and transmits S-polarized light selectively, or vice versa, and which is provided entirely at and in direct contact with the other major surface of the light conductive plate having the second liquid crystal display element,

wherein the reflector plate has an area facing the light conductive plate and only partially formed at an end area close to a boundary formed between the second liquid crystal display element and the reflector plate, so that the reflectance of the reflector plate gradually decreases according to a distance from the second liquid crystal display element in the area, and

wherein the area partially formed on the reflector plate is provided without overlapping any parts of the second liquid crystal display element relative to a back surface of the light conductive plate.