Collimating plate, lighting apparatus and liquid crystal display apparatus

• US 20010019378A1
• Filed: 02/14/2001
• Published: 09/06/2001
• Est. Priority Date: 02/14/2000
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Yamaguchi, Akira
• Granted Patent: US 6,876,408 B2
• Time in Patent Office: Days
• US Class Current: 349/61
• CPC Class Codes: G02B 3/0031 Replication or moulding, e.g. hot embossing, UV-casting, injection moulding
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 3/04 with continuous faces that are rotationally symmetrical but deviate from a true sphere , e.g. so called "aspheric" lenses
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133526 Lenses, e.g. microlenses or Fresnel lenses
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity

Abstract

The light collimating plate includes a lens substrate, a plurality of microlenses disposed on a surface of the lens substrate, a plurality of light entrance areas, each having a circular or rectangular form a center of which is on an optical axis of the microlens, and a light shield layer formed on another surface of the lens substrate, and covering other area than the light entrance areas. When n and t are a refractive index and a thickness of the lens substrate, respectively, and C (R; diameter, A, B; sides of rectangle) is a size of light entrance area, a size of the microlens Sr satisfies the following formula in the light collimating plate:

Sr≧2t×tan θ+C

(with the proviso that

θ=sin⁻¹(1/n)).

Or, a form of the microlens in the light collimating plate is a part of an ellipsoid shown in the following formula

X ² /a ² +y ² /a ² +z ² /c ² =1

(x and y represent axis on the surface of the lens substrate, z represents the optical axis), it'"'"'s accentricity ε is shown in the following formula

ε=(c²−a²)^½/c=1/n

and it'"'"'s far focal point is on a position of the light entrance area. The lighting apparatus and the liquid crystal display apparatus use the light collimating plate.

Claims

1. A collimating plate comprising:

a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas, each having a circular form a center of which is on an optical axis of each of said plurality of microlenses and set on another surface of the lens substrate reverse to said plurality of microlenses; and

a light shield layer formed on another surface of said lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein when a refractive index of said lens substrate is represented by n;

a thickness of said lens substrate by t;

a diameter of each of said plurality of light entrance areas by R; and

a size of each of said plurality of microlenses by Sr, the following formula (1);

Sr≧

2t×

tan θ

+R 

 

(1)

(with the proviso that θ

=sin<sup>−

1</sup>(1/n))

is satisfied.

2. The collimating plate according to

claim 1

, further comprising a diffuse reflecting layer formed at a light entrance side than said light shield layer so as to cover other area than said plurality of light entrance areas.

3. The collimating plate according to

claim 1

, wherein said plurality of microlenses are either in circular form when viewed from a direction of the optical axis and are arranged in a closest packing state or in hexagonal form when viewed from the direction of the optical axis and are arranged in a hexagonal close-packed state.

4. The collimating plate according to

claim 1

, wherein said refractive index of said lens substrate is between 1.4 and 2.

5. A lighting apparatus comprising:

a light source;

a lamp housing for containing said light source, whose inner surfaces are covered with a diffuse reflecting layer; and

a collimating plate,

wherein said collimating plate comprises a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas, each having a circular form a center of which is on an optical axis of each of said plurality of microlenses and set on another surface of the lens substrate reverse to said plurality of microlenses; and

a light shield layer formed on another surface of said lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein when a refractive index of said lens substrate is represented by n;

a thickness of said lens substrate by t;

a diameter of each of said plurality of light entrance areas by R; and

a size of each of said plurality of microlenses by Sr, the following formula (1);

Sr≧

2t×

tan θ

+R 

 

(1)

(with the proviso that θ

=sin<sup>−

1</sup>(1/n))

is satisfied.

6. A lighting apparatus comprising:

a collimating plate; and

a plurality of light sources,

wherein said collimating plate comprises a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas, each having a circular form a center of which is on an optical axis of each of said plurality of microlenses and set on another surface of the lens substrate reverse to said plurality of microlenses; and

a light shield layer formed on another surface of said lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein when a refractive index of said lens substrate is represented by n;

a thickness of said lens substrate by t;

a diameter of each of said plurality of light entrance areas by R; and

a size of each of said plurality of microlenses by Sr, the following formula (1);

Sr≧

2t×

tan θ

+R 

 

(1)

(with the proviso that θ

=sin<sup>−

1</sup>(1/n))

is satisfied, and

wherein said plurality of light sources are disposed in said plurality of light entrance areas of said collimating plate respectively.

7. The lighting apparatus according to

claim 6

, wherein a light emission size of each of said plurality of light sources is smaller than a size of each of said plurality of light entrance areas.

8. The lighting apparatus according to

claim 6

, wherein said plurality of light sources are LEDs or organic EL devices.

9. A liquid crystal display apparatus comprising:

a liquid crystal display panel; and

a lighting apparatus for launching light into said liquid crystal display panel,

wherein said lighting apparatus comprises a light source;

a lamp housing for containing said light source, whose inner surfaces are covered with a diffuse reflecting layer; and

a collimating plate,

wherein said collimating plate comprises a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas, each having a circular form a center of which is on an optical axis of each of said plurality of microlenses and set on another surface of the lens substrate reverse to said plurality of microlenses; and

a light shield layer formed on another surface of said lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein when a refractive index of said lens substrate is represented by n;

a thickness of said lens substrate by t;

a diameter of each of said plurality of light entrance areas by R; and

a size of each of said plurality of microlenses by Sr, the following formula (1);

Sr≧

2t×

tan θ

+R 

 

(1)

(with the proviso that θ

=sin<sup>−

1</sup>(1/n))

is satisfied.

10. The liquid crystal display apparatus according to

claim 9

, further comprising a light diffusing plate for diffusing an image-bearing light which has passed through said liquid crystal display panel.

11. A liquid crystal display apparatus comprising:

a liquid crystal display panel; and

a lighting apparatus for launching light into said liquid crystal display panel,

wherein said lighting apparatus comprises a collimating plate; and

a plurality of light sources,

wherein said collimating plate comprises a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas, each having a circular form a center of which is on an optical axis of each of said plurality of microlenses and set on another surface of the lens substrate reverse to said plurality of microlenses; and

a light shield layer formed on another surface of said lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein when a refractive index of said lens substrate is represented by n;

a thickness of said lens substrate by t;

a diameter of each of said plurality of light entrance areas by R; and

a size of each of said plurality of microlenses by Sr, the following formula (1);

Sr≧

2t×

tan θ

+R 

 

(1)

(with the proviso that θ

=sin<sup>−

1</sup>(1/n))

is satisfied, and

wherein said plurality of light sources are disposed in said plurality of light entrance areas of said collimating plate respectively.

12. A collimating plate comprising:

a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas, each having a rectangular form a center of which is on an optical axis of each of said plurality of microlenses and set on another surface of the lens substrate reverse to said plurality of microlenses; and

a light shield layer formed on another surface of said lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein, when a refractive index of said lens substrate is represented by n;

a thickness of said lens substrate by t;

a length of a side of each of said plurality of light entrance areas by A;

a length of another side of each of said plurality of light entrance areas by B;

a size of each of said plurality of microlenses in a direction of said length A represented by Sa; and

a size of each of said plurality of microlenses in a direction of said length B represented by Sb, the following formulae (2) and (3);

Sa≧

2t×

tan θ

+A 

 

(2) Sb≧

2t×

tan θ

+B 

 

(3)

(with the proviso that θ

=sin<sup>−

1</sup>(1/n))

are satisfied.

13. The collimating plate according to

claim 12

, wherein said plurality of microlenses are either in square form viewed from a direction of the optical axis and are arranged in a square closed-packed state or in rectangular form viewed from the direction of the optical axis and are arranged in a rectangular closed-packed state.

14. A lighting apparatus comprising:

a light source;

a lamp housing for containing said light source, whose inner surfaces are covered with a diffuse reflecting layer; and

a collimating plate,

wherein said collimating plate comprises a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas, each having a rectangular form a center of which is on an optical axis of each of said plurality of microlenses and set on another surface of the lens substrate reverse to said plurality of microlenses; and

a light shield layer formed on another surface of said lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein, when a refractive index of said lens substrate is represented by n;

a thickness of said lens substrate by t;

a length of a side of each of said plurality of light entrance areas by A;

a length of another side of each of said plurality of light entrance areas by B;

a size of each of said plurality of microlenses in a direction of said length A represented by sa; and

a size of each of said plurality of microlenses in a direction of said length B represented by Sb, the following formulae (2) and (3);

Sa≧

2t×

tan θ

+A 

 

(2) Sb≧

2t×

tan θ

+B 

 

(3)

(with the proviso that θ

=sin<sup>−

1</sup>(1/n))

are satisfied.

15. A lighting apparatus comprising:

a collimating plate; and

a plurality of light sources,

wherein said collimating plate comprises a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas, each having a rectangular form a center of which is on an optical axis of each of said plurality of microlenses and set on another surface of the lens substrate reverse to said plurality of microlenses; and

a light shield layer formed on another surface of said lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein, when a refractive index of said lens substrate is represented by n;

a thickness of said lens substrate by t;

a length of a side of each of said plurality of light entrance areas by A;

a length of another side of each of sa d plurality of light entrance areas by B;

a size of each of said plurality of microlenses in a direction of said length A represented by Sa; and

a size of each of said plurality of microlenses in a direction of said length B represented by Sb, the following formulae (2) and (3);

Sa≧

2t×

tan θ

+A 

 

(2) Sb≧

2t×

tan θ

+B 

 

(3)

(with the proviso that θ

=sin<sup>−

1</sup>(1/n))

are satisfied, and

wherein said plurality of light sources are disposed in said plurality of light entrance areas of said collimating plate respectively.

16. A liquid crystal display apparatus comprising:

a liquid crystal display panel; and

a lighting apparatus for launching light into said liquid crystal display panel,

wherein said lighting apparatus comprises a light source;

a lamp housing for containing said light source, whose inner surf aces are covered with a diffuse reflecting layer; and

a collimating plate,

wherein said collimating plate comprises a lens substrate;

a plurality of microlenses disposed on a surf ace of said lens substrate;

a plurality of light entrance areas, each having a rectangular form a center of which is on an optical axis of each of said plurality of microlenses and set on another surface of the lens substrate reverse to said plurality of microlenses; and

a light shield layer formed on another surface of said lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein, when a refractive index of said lens substrate is represented by n;

a thickness of said lens substrate by t;

a length of a side of each of said plurality of light entrance areas by A;

a length of another side of each of said plurality of light entrance areas by B;

a size of each of said plurality of microlenses in a direction of said length A represented by Sa; and

a size of each of said plurality of microlenses in a direction of said length B represented by Sb, the following formulae (2) and (3);

Sa≧

2t×

tan θ

+A 

 

(2) Sb≧

2t×

tan θ

+B 

 

(3)

(with the proviso that θ

=sin<sup>−

1</sup>(1/n))

are satisfied.

17. A liquid crystal display apparatus comprising:

a liquid crystal display panel; and

a lighting apparatus for launching light into said liquid crystal display panel,

wherein said lighting apparatus comprises a collimating plate; and

a plurality of light sources,

wherein said collimating plate comprises a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas, each having a rectangular form a center of which is on an optical axis of each of said plurality of microlenses and set on another surface of the lens substrate reverse to said plurality of microlenses; and

a light shield layer formed on another surface of said lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein, when a refractive index of said lens substrate is represented by n;

a thickness of said lens substrate by t;

a length of a side of each of said plurality of light entrance areas by A;

a length of another side of each of said plurality of light entrance areas by B;

a size of each of said plurality of microlenses in a direction of said length A represented by Sa; and

a size of each of said plurality of microlenses in a direction of said length B represented by Sb, the following formulae (2) and (3);

Sa≧

2t×

tan θ

+A 

 

(2) Sb≧

2t×

tan θ

+B 

 

(3)

(with the proviso that θ

=sin<sup>−

1</sup>(1/n))

are satisfied, and

wherein said plurality of light sources are disposed in said plurality of light entrance areas of said collimating plate respectively.

18. A collimating plate comprising:

a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas disposed on another surface of said lens substrate reverse to said plurality of microlenses, and having an optical axis of each of said plurality of microlenses; and

a light shield layer formed on said another surface of the lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein a form of each of said plurality of microlenses is a part of an ellipsoid shown in the following formula (4),

wherein an eccentricity ε

of said ellipsoid is shown in the following formula (5) and

wherein, in said ellipsoid, a focal point away from a side from which light is issued is on a position of each of said plurality of light entrance areas;

X²/a²+y²/a²+z²/c²=1 

 

(4) ε

=(c²−

a²)^½

/c=1/n 

 

(5)

wherein x and y represent axes on the surface of the lens substrate;

z represents the optical axis; and

n represents a refractive index of a material forming said plurality of microlenses.

19. The collimating plate according to

claim 18

, wherein said plurality of microlenses are either in circular form viewed from a direction of the optical axis and are arranged in a closest packing state, or in hexagonal form viewed from the direction of the optical axis and are arranged in a hexagonal close-packed state.

20. A lighting apparatus comprising:

a light source;

a lamp housing for containing said light source, whose inner surfaces are covered with a diffuse reflecting layer; and

a collimating plate,

wherein said collimating plate comprises a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas disposed on another surface of said lens substrate reverse to said plurality of microlenses, and having an optical axis of each of said plurality of microlenses; and

a light shield layer formed on said another surface of the lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein a form of each of said plurality of microlenses is a part of an ellipsoid shown in the following formula (4),

wherein an eccentricity ε

of said ellipsoid is shown in the following formula (5) and

wherein, in said ellipsoid, a focal point away from a side from which light is issued is on a position of each of said plurality of light entrance areas;

X²/a²+y²/a²+z²/c²=1 

 

(4) ε

=(c²−

a²)^½

/c=1/n 

 

(5)

wherein x and y represent axes on the surface of the lens substrate;

z represents the optical axis; and

n represents a refractive index of a material forming said plurality of microlenses.

21. A lighting apparatus comprising:

a collimating plate; and

a plurality of light sources,

wherein said collimating plate comprises a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas disposed on another surface of said lens substrate reverse to said plurality of microlenses, and having an optical axis of each of said plurality of microlenses; and

a light shield layer formed on said another surface of the lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein a form of each of said plurality of microlenses is a part of an ellipsoid shown in the following formula (4),

wherein an eccentricity ε

of said ellipsoid is shown in the following formula (5) and

wherein, in said ellipsoid, a focal point away from a side from which light is issued is on a position of each of said plurality of light entrance areas;

X²/a²+y²/a²+z²/c²=1 

 

(4) ε

=(c²−

a²)^½

/c=1/n 

 

(5)

wherein x and y represent axes on the surface of the lens substrate;

z represents the optical axis; and

n represents a refractive index of a material forming said plurality of microlenses, and

wherein said plurality of light sources are disposed in said plurality of light entrance areas of said collimating plate respectively.

22. A liquid crystal display apparatus comprising:

a liquid crystal display panel; and

a lighting apparatus for launching light into said liquid crystal display panel,

wherein said lighting apparatus comprises a light source;

a lamp housing for containing said light source, whose inner surfaces are covered with a diffuse reflecting layer; and

a collimating plate,

wherein said collimating plate comprises a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas disposed on another surface of said lens substrate reverse to said plurality of microlenses, and having an optical axis of each of said plurality of microlenses; and

a light shield layer formed on said another surface of the lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein a form of each of said plurality of microlenses is a part of an ellipsoid-shown in the following formula (4),

wherein an eccentricity ε

of said ellipsoid is shown in the following formula (5) and

wherein, in said ellipsoid, a focal point away from a side from which light is issued is on a position of each of said plurality of light entrance areas;

X²/a²⁺y²/a²+z²/c²=1 

 

(4) ε

=(c²−

a²)^½

/c=1/n 

 

(5)

wherein x and y represent axes on the surface of the lens substrate;

z represents the optical axis; and

n represents a refractive index of a material forming said plurality of microlenses.

23. A liquid crystal display apparatus comprising:

a liquid crystal display panel; and

a lighting apparatus for launching light into said liquid crystal display panel,

wherein said lighting apparatus comprises a collimating plate; and

a plurality of light sources,

wherein said collimating plate comprises a lens substrate;

a plurality of microlenses disposed on a surface of said lens substrate;

a plurality of light entrance areas disposed on another surface of said lens substrate reverse to said plurality of microlenses, and having an optical axis of each of said plurality of microlenses; and

a light shield layer formed on said another surface of the lens substrate reverse to said plurality of microlenses so as to cover other area than said plurality of light entrance areas,

wherein a form of each of said plurality of microlenses is a part of an ellipsoid shown in the following formula (4),

wherein an eccentricity ε

of said ellipsoid is shown in the following formula (5) and

wherein, in said ellipsoid, a focal point away from a side from which light is issued is on a position of each of said plurality of light entrance areas;

X²/a²+y²/a²+z²/c²=1 

 

(4) ε

=(c²−

a²)^½

/c=1/n 

 

(5)

wherein x and y represent axes on the surface of the lens substrate;

z represents the optical axis; and

n represents a refractive index of a material forming said plurality of microlenses, and

wherein said plurality of light sources are disposed in said plurality of light entrance areas of said collimating plate which are surrounded with said light shield layer and said diffuse reflecting layer.