Input device with optical module for determining a relative position of an object thereon

• US 9,285,926 B2
• Filed: 07/20/2012
• Issued: 03/15/2016
• Est. Priority Date: 11/17/2011
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Yang, Feng-Cheng, Chung, Ching-Lin, Chen, Hsin-Chia, Chen, Hui-Hsuan
• Primary Examiner(s): Spar, Ilana
• Assistant Examiner(s): Hermann, Kirk
• Application Number:
  US13/554,052
• Publication Number:
  US 20130127713A1
• Time in Patent Office: 1,334 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04109 FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

An input device comprising an optical module having a light guide plate, a light source, a scattering layer and a sensor is provided. The light guide plate has a top surface, a bottom surface, and a side. The light source emits a light to the side. The light travels within the light guide plate. The scattering layer changes a path of parts of the light on the bottom surface so that the light is projected out of the top surface to form a penetrating light. When an object approaches or touches the top surface of the light guide plate, at least a part of the penetrating light is reflected by the object to form a reflected light received by the sensor. According to the reflected light, the input device generates a position signal indicating at least one relative position of the object with respect to the top surface.

Claims

1. An input device, comprising:

an optical module, comprising;

a light guide plate, being made of a transparent material, having a top surface, a bottom surface opposite the top surface, and a side, wherein the transparent material makes the light travel in a way of total reflection between the top surface and the bottom surface within the light guide plate;

a light source, being disposed adjacent to the side of the light guide plate to emit a light to the side, the light traveling within the light guide plate;

a scattering layer, being formed on the bottom surface and being configured to change a reflection path of the partial light hitting on the bottom surface so that the partial light is projected out of the top surface by the scattering layer to form a penetrating light; and

a sensor, having a viewing angle covering at least a part of the bottom surface of the light guide plate, wherein when an object approaches or touches the top surface of the light guide plate, at least a part of the penetrating light is reflected by the object to form a reflected light passing through the light guide plate and then being received by the sensor, and the input device generates a position signal according to the reflected light, the position signal indicating at least one relative position of the object with respect to the top surface of the light guide plate;

wherein the sensor further continuously receives the reflected light so that the input device determines a variance of the at least one relative position over time according to the position signal;

wherein the input device is a mouse, the optical module is used as a mouse wheel, and the variance is used by the input device to generate a control signal which represents one of a 360°

scroll action, a click action and a combination thereof.

2. The input device of claim 1, wherein the optical module further comprises a lens disposed between the light guide plate and the sensor, and the reflected light reflected by the object penetrates the light guide plate and is focused by the lens onto the sensor.

3. The input device of claim 1, wherein the variance includes a horizontal component and a vertical component, the horizontal component represents an amount of movement of the object along a first direction of the top surface, the vertical component represents an amount of movement of the object along a second direction of the top surface, and the first direction and the second direction are orthogonal.

4. The input device of claim 1, wherein the scattering layer is formed by coating an optical scattering material on the bottom surface.

5. The input device of claim 1, wherein the scattering layer is formed by etching the bottom surface to form a plurality of recesses in the bottom surface.

6. The input device of claim 1, wherein the light source is a light emitting diode (LED), and the light is one of a visible light, an invisible light and a combination thereof.

7. The input device of claim 1, further comprising at least one another light source disposed adjacent to the light guide plate.

8. An input device, comprising:

an optical module, comprising;

a light guide plate, being made of a transparent material, having a top surface, a bottom surface opposite the top surface, and a side, wherein the transparent material makes the light travel in a way of total reflection between the top surface and the bottom surface within the light guide plate;

a light source, being disposed adjacent to the side of the light guide plate to emit a light to the side, the light traveling within the light guide plate;

a scattering layer, being formed by coating an optical scattering material on the bottom surface and being configured to change a reflection path of the partial light hitting on the bottom surface so that the partial light is projected out of the top surface by the scattering layer to form a penetrating light; and

a sensor, having a viewing angle covering at least a part of the bottom surface of the light guide plate, wherein when an object approaches or touches the top surface of the light guide plate, at least a part of the penetrating light is reflected by the object to form a reflected light passing through the light guide plate and then being received by the sensor, and the input device generates a position signal according to the reflected light, the position signal indicating at least one relative position of the object with respect to the top surface of the light guide plate.

9. The input device of claim 8, wherein the optical module further comprises a lens disposed between the light guide plate and the sensor, and the reflected light reflected by the object penetrates the light guide plate and is focused by the lens onto the sensor.

10. The input device of claim 8, wherein the sensor further continuously receives the reflected light so that the input device determines a variance of the at least one relative position over time according to the position signal.

11. The input device of claim 10, wherein the input device is a mouse, the optical module is used as a mouse wheel, and the variance is used by the input device to generate a control signal which represents one of a 360°

scroll action, a click action and a combination thereof.

12. The input device of claim 11, wherein the variance includes a horizontal component and a vertical component, the horizontal component represents an amount of movement of the object along a first direction of the top surface, the vertical component represents an amount of movement of the object along a second direction of the top surface, and the first direction and the second direction are orthogonal.

13. The input device of claim 10, wherein the input device is a trackpad, and the variance is used by the input device to generate a control signal which represents one of a pointer moving action, a click action and a combination thereof.

14. The input device of claim 13, wherein the variance includes a horizontal component and a vertical component, the horizontal component represents an amount of movement of the object along a first direction of the top surface, the vertical component represents an amount of movement of the object along a second direction of the top surface, and the first direction and the second direction are orthogonal.

15. The input device of claim 8, wherein the light source is a light emitting diode (LED), and the light is one of a visible light, an invisible light and a combination thereof.

16. The input device of claim 8, further comprising at least one another light source disposed adjacent to the light guide plate.