Illuminated button backlighted by white light

• US 6,148,075 A
• Filed: 07/08/1998
• Issued: 11/14/2000
• Est. Priority Date: 08/27/1997
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Saito, Koji, Inoue, Tsutomu, Inubushi, Toshiya
• Primary Examiner(s): Chiang, Jack
• Application Number:
  US09/112,019
• Time in Patent Office: 860 Days
• Field of Search: 379/433, 379/428, 379/368-370, 200/314, 455/90, 455/575
• US Class Current: 379/368
• CPC Class Codes: G09F 13/04 Signs, boards or panels, illuminated from behind the insignia
• CPC Class Codes: H01H 2219/018 Electroluminescent panel
• CPC Class Codes: H01H 2221/002 integral with membrane
• CPC Class Codes: H01H 2221/07 transparent
• CPC Class Codes: H04M 1/22 Illumination; Arrangements for improving the visibility of characters on dials

Abstract

An illuminated button including a key button and an electroluminescent light (EL) for illuminating the key button from its bottom. The key button is composed of a silicone rubber material mixed with white color particles which prevent, while the EL is inoperative, a pink light reflected from the EL from being projected to the outside through the key button. This makes possible to solve a problem of a conventional illuminated button, which includes a key button and a white light EL used as a backlight, in that the pink color of the EL is seen from the outside through the key button, and this spoils the beauty of the illuminated button.

Claims

1. An illuminated button, comprising:

a key button composed of a light transmission material;

an electroluminescent light source, disposed on a bottom side of said key button, for illuminating, while said electroluminescent light source is operative, said key button from its bottom side;

switch contacts for producing a key operation signal when said key button is depressed; and

means for attenuating reflected light from said electroluminescent light while it is inoperative, said attenuating means functioning to prevent light reflected by said electroluminescent light source from being projected through said key button when said electroluminescent light source is not operative.

2. The illuminated button as claimed in claim 1, wherein said attenuating means is composed of a material with a light transmission repression property.

3. The illuminated button as claimed in claim 1, wherein said attenuating means is composed of a material with a light scattering property.

4. The illuminated button as claimed in claim 1, wherein said attenuating means comprises color particles mixed into said light transmission material constituting said key button.

5. The illuminated button as claimed in claim 4, wherein a color of said color particles belongs to a same color family as that of light emitted from said electroluminescent light to backlight said key button.

6. The illuminated button as claimed in claim 5, wherein both said color particles and the light that backlights said key button are white.

7. The illuminated button as claimed in claim 1, wherein said means for attenuating comprises a light transmission color print formed on the bottom of said key button.

8. The illuminated button as claimed in claim 7, wherein a color of said light transmission color print belongs to a same color family as that of light emitted from said electroluminescent light to backlight said key button.

9. The illuminated button as claimed in claim 8, wherein both said light transmission color print and said light that backlights said key button are white.

10. The illuminated button as claimed in claim 1, wherein said attenuating means comprises a matte surface formed on top of said key button.

11. The illuminated button as claimed in claim 1, wherein said attenuating means comprises a semi-transparent reflection sheet disposed between said key button and said electroluminescent light.

12. The illuminated button as claimed in claim 11, wherein said semi-transparent sheet is disposed on a surface of said electroluminescent light.

13. The illuminated button as claimed in claim 1, wherein said attenuating means comprises a semi-transparent reflection material printed on a surface of said electroluminescent light.

14. The illuminated button as claimed in claim 1, wherein said attenuating means comprises a light scattering prism sheet disposed between said key button and said electroluminescent light.

15. The illuminated button as claimed in claim 1, wherein said attenuating means comprises a base film constituting said electroluminescent light, and wherein said base film has undergone a light transmission repression processing.

16. The illuminated button as claimed in claim 15, wherein said light transmission repression processing is a matte processing applied to a surface of said base film.

17. The illuminated button as claimed in claim 15, wherein said light transmission repression processing is a processing to form a plurality of microscopic triangular asperities on the surface of said base film.

18. The illuminated button as claimed in claim 15, wherein said base film consists of a semi-transparent sheet.

19. The illuminated button as claimed in claim 1, wherein said key button comprises a letter print formed on its top.

20. An illuminated button pad including a plurality of illuminated buttons, each of the illuminated buttons comprising:

a key button composed of a light transmission material;

an electroluminescent light source, disposed on a bottom side of said key button, for illuminating, while said electroluminescent light source is operative, said key button from its bottom side;

switch contacts for producing a key operation signal when said key button is depressed; and

means for attenuating reflected light from said electroluminescent light while it is inoperative, said attenuating means functioning to prevent light reflected by said electroluminescent light source from being projected through said key button when said electroluminescent light source is not operative.