Multifunctional-type backlight unit and information device using said backlight unit

• US 20060262562A1
• Filed: 05/09/2006
• Published: 11/23/2006
• Est. Priority Date: 05/10/2005
• Status: Active Grant

• Current Assignee: Citizen Electronics Company Limited
• Original Assignee: Citizen Electronics Company Limited
• Inventors: Fukasawa, Koichi, Ishizaka, Mitsunori
• Granted Patent: US 7,517,132 B2
• Time in Patent Office: Days
• US Class Current: 362/615
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources

Abstract

A multifunctional-type backlight unit, including a light guiding plate having a first incident/exit surface and a second incident/exit surface which are capable of receiving and emitting light, a light emitting device disposed to face the first incident/exit surface and configured to supply light to the first incident/exit surface, and a light receiving device disposed to face the first incident/exit surface and configured to receive light emitted from the first incident/exit surface, the light guiding plate being configured so that the light emitted from the light emitting device enters the light guiding plate, passes through the light guiding plate, and is emitted from the second incident/exit surface, and the light guiding plate being configured so that the light which enters the second incident/exit surface, passes through the light guiding plate emits from the first incident/exit surface is received by the light receiving device.

Claims

1. A multifunctional-type backlight unit, comprising:

a light guiding plate including a first incident/exit surface and a second incident/exit surface which are capable of inputting and outputting light;

a light emitting device disposed to face the first incident/exit surface and configured to supply light to the first incident/exit surface; and

a light receiving device disposed to face the first incident/exit surface and configured to receive light emitted from the first incident/exit surface,

wherein the light guiding plate is configured so that the light emitted from the light emitting device enters the first incident/exit surface, passes through the light guiding plate, and is emitted from the second incident/exit surface, and

wherein the light guiding plate is configured so that the light enters the second incident/exit surface, passes through the light guiding plate, and is emitted from the first incident/exit surface to the light receiving device.

2. The multifctional-type backlight unit according to claim 1,

wherein the light emitting device includes at least one light source disposed to face the first incident/exit surface.

3. The multifunctional-type backlight unit according to claim 1,

wherein the light receiving device including at least one light receiving element is disposed to face the first incident/exit surface.

4. The multifunctional-type backlight unit according to claim 1,

wherein the first incident/exit surface is provided on one side surface of the light guiding plate,

wherein the second incident/exit surface is provided on an upper surface of the light guiding plate,

wherein a plurality of grooves, each of which has a generally triangular shape in section and extends generally in parallel with a long side of the first incident/exit surface and is cut into the light guiding plate toward the second incident/exit surface are provided on a lower surface of the light guiding plate at predetermined intervals,

wherein the light guiding plate is configured to reflect light entering the first incident/exit surface on the grooves and output the light from the second incident/exit surface, and

wherein the light guiding plate is configured to collect incident light entering the second incident/exit surface from outside by the grooves and output the light from the first incident/exit surface.

5. The multiflnctional-type backlight unit according to claim 1,

wherein the light emitting device includes at least one light source, a backlight drive circuit to drive the light source as a backlight, and a transmitting drive circuit to drive the light source as a transmitter of information.

6. The multifunctional-type backlight unit according to claim 5,

wherein the light emitting device further includes a switching circuit to allow selection of drive using either the backlight drive circuit or the transmitting drive circuit.

7. The multifunctional-type backlight unit according to claim 6,

wherein the light emitting device firther includes a control circuit connected to the switching circuit and configured to control the switching circuit so that the switching circuit switches to select drive using either the backlight drive circuit or the transmitting drive circuit.

8. The multifunctional-type backlight unit according to claim 1,

wherein the light receiving device includes at least one light receiving element disposed to face the first incident/exit surface, an amplification circuit to amplify a light receiving signal from the light receiving element and a control circuit configured to receive as input an output signal from the amplification circuit.

9. The multifuinctional-type backlight unit according to claim 1,

wherein the light emitting device includes at least one light source and a backlight drive circuit to drive the light source as a backlight,

wherein the light source is a light emitting diode emitting visible light,

wherein the visible light emitted from the light emitting diode is controlled in response to a backlight drive signal from the backlight drive circuit,

wherein the light guiding plate is configured to output the visible light entering the first incident/exit surface as backlight from the second incident/exit surface.

10. The multifunctional-type backlight unit according to claim 1,

wherein the light emitting device includes at least one light source and a transmitting drive circuit to drive the light source as a transmitter of information,

wherein the light source is a light emitting diode to emitting visible light,

wherein the visible light emitted from the light emitting diode is modulated in response to a transmitting drive signal from the transmitting drive circuit,

wherein the light guiding plate is configured to output the modulated visible light entering the first incident/exit surface as information to be sent to an external device from the second incident/exit surface.

11. The multifunctional-type backlight unit according to claim 8,

wherein the light receiving element receives light which enters the second incident/exit surface of the light guiding plate, is collected by the light guiding plate and emitted from the first incident/exit surface of the light guiding plate and outputs the light receiving signal depending on the intensity of the light entering the second incident/exit surface,

wherein the control circuit demodulates the output signal from the amplification circuit to receive information from an external device.

12. The multifinctional-type backlight unit according to claim 8,

wherein the light emitting device includes at least one light source and a backlight drive circuit to drive the light source as a backlight,

wherein the light receiving element is disposed to face the first incident/exit surface,

wherein the light receiving element receives light which enters the second incident/exit surface of the light guiding plate, is collected by the light guiding plate and emitted from the first incident/exit surface of the light guiding plate and outputs the light receiving signal, depending on the intensity of the light entering the second incident/exit surface,

wherein the control circuit is configured to control the backlight drive circuit in response to the output signal from the amplification circuit and adjust the amount of visible light emitted from the light source.

13. An information device, comprising:

the multifunctional-type backlight unit as recited in claim 1;

and

a display;

wherein a backlight for the display is comprised of the multifunctional-type backlight unit,

wherein the multifunctional-type backlight unit is configured to execute information transmission by way of an exterior device and visible light.

14. An information device., comprising:

the multifunctional-type backlight unit as recited in claim 1;

and

a display having a light receiving surface;

wherein the light receiving surface of the display is disposed to face the second light incident/exit surface of the multifunctional-type backlight unit,

wherein the multifunctional-type backlight unit is configured to adjust intensity of backlight for the display in response to ambient light.

15. An information device, comprising:

the multifunctional-type backlight unit as recited in claim 1;

a display having a light receiving surface; and

a secondary battery,

wherein the light receiving surface of the display is disposed to face the second light incident/exit surface of the multifinctional-type backlight unit,

wherein the light receiving element of the multifunctional-type backlight unit is a solar battery,

wherein the multifunctional-type backlight unit has a charging circuit configured to charge the secondary battery using a light receiving signal from the solar battery.

16. The information device according to any one of claims 13,

wherein the information device is a mobile phone, a personal computer, an information terminal, or an information device for a vehicle.

17. The information device according to any one of claims 14,

wherein the information device is a mobile phone, a personal computer, an information terminal, or an information device for a vehicle.

18. The information device according to any one of claims 15,

wherein the information device is a mobile phone, a personal computer, an information terminal, or an information device for a vehicle.