Optical navigation module and mobile electronic appliance using optical navigation module

1. An optical navigation module comprising:

a light transmission window comprising a navigation surface;

a light source located under the transmission window;

a first light shield configured for blocking ambient light;

a sensor located under the transmission window;

a second light shield located between the light source and the sensor and configured for blocking direct light from the light source to the sensor;

wherein the light transmission window comprises a first refraction surface on the top of the light source to refract the light and change a direction of the light towards the top navigation surface and a second refraction surface to refract back-scattered light, change a direction of the back-scattered light and guide the back-scattered light from the top navigation surface towards the sensor for sensing relative object movement;

wherein the light transmission window further comprises a top navigation surface, a first lens and a second lens; the top navigation surface is the same height as a top surface of the first light shield; the first lens is on the first refraction surface, the first lens transforms the light from the light source to a desirable size; the second lens is on the second refraction surface; two cavities are formed underneath the first light shield and separated by the second light shield; and the sensor and the light source are placed in the two cavities respectively; wherein a top part of the second light shield is inserted into the light transmission window; a top surface of the second light shield is lower than the top surface of the first light shield, and the top surface of the second light shield is higher than a bottom surface of the light transmission window and is higher than a bottom surface of the first light shield; and

wherein the first light shield and the second light shield are molded together with the light transmission window.

2. The optical navigation module of claim 1 , wherein the light source is a top-emitting laser that emits a coherent optical radiation with a single lateral mode or the light source is a single-mode vertical cavity surface emitting laser.

3. The optical navigation module of claim 1 , wherein the light transmission window is fabricated using a material with refractive index between 1.5 and 1.8.

4. The optical navigation module of claim 1 , wherein the first refraction surface has an angle which is about 50 degrees.

5. The optical navigation module of claim 1 , wherein the second refraction surface has an angle which is in the range of about 60 degrees to about 80 degrees.

6. The optical navigation module of claim 1 , wherein the distance between the top surface of the light source and the top navigation surface is in the range of about 0.5 mm to about 1.0 mm.

7. The optical navigation module of claim 1 , wherein the sensor comprises a photodiode array, the back-scattered light from the external moving object forms a speckle pattern on the photodiode array and the sensor detects the movement of the speckle pattern across the photodiode array to determine the relative movement of the object.

8. The optical navigation module of claim 7 , wherein the distance between the light source center to the near edge of photodiode array is between about 1.7 mm and about 2.3 mm.

9. The optical navigation module of claim 7 , wherein the sensor is positioned in such an arrangement that receives the maximum back-scattered light by the object when the object is placed on the top navigation surface and the back-scattered light reaching the photodiode array is reduced significantly when the external moving object is lifted off the top navigation surface.

10. The optical navigation module of claim 1 , wherein the first and second refraction surfaces are coated with anti-reflection coating.

11. The optical navigation module of claim 1 further comprises a PCB substrate, the sensor and the light source are electrically bonded onto the PCB substrate.

12. The optical navigation module of claim 11 further comprises a switch which is attached at the bottom side of the PCB substrate.

13. The optical navigation module of claim 11 , wherein the distance from the top navigation surface to the PCB substrate bottom is between about 1.2 mm and about 1.5 mm.

14. The optical navigation module of claim 1 , wherein the sensor is located at a lower lateral of the light transmission window which is not directly under the light transmission window.

15. An optical navigation module comprising:

a light source;

a light transmission window comprising a navigation surface;

a first light shield configured for blocking the ambient light;

a sensor configured for detecting light from the light transmission window;

a second light shield located between the light source and the sensor and configured for blocking the direct light from the light source to the sensor;

wherein the light transmission window comprises at least one refraction surface, the refraction surface is positioned in the light path from the light source to the sensor and changes a direction of the light; two cavities are formed underneath the first light shield and separated by the second light shield; and the sensor and the light source are placed in the two cavities respectively; and

wherein a top part of the second light shield is inserted into the light transmission window; the top surface of the second light shield is lower than the top surface of the first light shield, and the top surface of the second light shield is higher than the bottom surface of the light transmission window and is higher than a bottom surface of the first light shield.

16. The optical navigation module of claim 15 , wherein the refraction surface is positioned in the light path from the light source to the top navigation surface.

17. The optical navigation module of claim 15 , wherein the refraction surface is positioned in the light path from the top navigation surface to the sensor.

18. A mobile electronic appliance comprising the optical navigation module of claim 15 .

19. The mobile electronic appliance of claim 18 , wherein the optical navigation module further comprises a PCB substrate, the sensor and the light source are electrically bonded onto the PCB substrate.

20. The mobile electronic appliance of claim 19 , wherein the optical navigation module further comprises a switch which is attached at the bottom side of the PCB substrate.

21. The mobile electronic appliance of claim 19 wherein the distance from the top navigation surface to the PCB substrate bottom is between about 1.2 mm and about 1.5 mm.

22. The mobile electronic appliance of claim 18 , wherein the mobile electronic appliance comprises an ultra-thin mobile phone, a laptop PC, or a tablet PC.

23. The mobile electronic appliance of claim 18 , wherein the refraction surface is positioned in the light path from the light source to the top navigation surface.

24. The mobile electronic appliance of claim 18 , wherein the refraction surface is positioned in the light path from the top navigation surface to the sensor.

25. The mobile electronic appliance of claim 18 , wherein the light source is a top-emitting laser that emits a coherent optical radiation with a single lateral mode.

26. The mobile electronic appliance of claim 18 , wherein the light source is a single-mode vertical cavity surface emitting laser.

27. The mobile electronic appliance of claim 18 , wherein the light transmission window is fabricated using a material with refractive index between 1.5 and 1.8.

28. The mobile electronic appliance of claim 18 , wherein the first refraction surface has an angle which is about 50 degrees.

29. The mobile electronic appliance of claim 18 , wherein the second refraction surface has an angle which is in the range of about 60 degrees to about 80 degrees.

30. The mobile electronic appliance of claim 18 , wherein the distance between the top surface of the light source and the top navigation surface is in the range of about 0.5 mm to about 1.0 mm.

31. The mobile electronic appliance of claim 18 , wherein the sensor comprises a photodiode array, the back-scattered light from the external moving object forms a speckle pattern on the photodiode array and the sensor detects the movement of the speckle pattern across the photodiode array to determine the relative movement of the object.

32. The mobile electronic appliance of claim 31 , wherein the distance between the light source center to the near edge of photodiode array is between about 1.7 mm and about 2.3 mm.

33. The mobile electronic appliance of claim 31 , wherein the sensor is positioned in such an arrangement that receives the maximum back-scattered light by the object when the object is place on the top navigation surface and the back-scattered light reaching the photodiode array will be reduced significantly when the external moving object is lifted off the top navigation surface.

34. The mobile electronic appliance of claim 18 , wherein the first light shield and the light transmission window are molded into one single part.

35. The mobile electronic appliance of claim 18 , wherein the first and second refraction surfaces are coated with anti-reflection coating.

36. The mobile electronic appliance of claim 18 , wherein at least one of the first and second refraction surfaces contains a lens.

37. The mobile electronic appliance of claim 18 , wherein the light transmission window further comprises a top navigation surface, and the top navigation surface is the same height as a top surface of the first light shield.

38. The mobile electronic appliance of claim 18 , wherein the light transmission window further comprises a first lens which is on the refraction surface, and the first lens transforms the light from the light source to a desirable size.

39. The optical navigation module of claim 15 , wherein the sensor is located at a lower lateral of the light transmission window which is not directly under the light transmission window.