OPTICALLY BASED PLANAR SCANNER

• US 20110063604A1
• Filed: 09/09/2010
• Published: 03/17/2011
• Est. Priority Date: 09/11/2009
• Status: Active Grant

• Current Assignee: Morphotrust USA Incorporated (Advent International Corporation)
• Original Assignee: Identix, Inc. (Advent International Corporation)
• Inventors: Maase, Daniel F., Hamre, John D.
• Granted Patent: US 8,354,640 B2
• Time in Patent Office: Days
• US Class Current: 356/71
• CPC Class Codes: G02B 6/4214 the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device G02B6/4246 takes precedence
• CPC Class Codes: G02F 1/1326 Liquid crystal optical waveguides or liquid crystal cells specially adapted for gating or modulating between optical waveguides
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/295 Analog deflection from or in an optical waveguide structure]
• CPC Class Codes: G02F 2201/307 Reflective grating, i.e. Bragg grating
• CPC Class Codes: G02F 2203/62 Switchable arrangements whereby the element being usually not switchable
• CPC Class Codes: G06V 40/1318 using electro-optical elements or layers, e.g. electroluminescent sensing
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 31/02327 the optical elements being integrated or being directly associated to the device, e.g. back reflectors optical coatings H01L31/0216

Abstract

Apparatus and methods for providing an optically based planar scanner for generating an image are provided. In one embodiment, the apparatus includes a switchable Bragg grating. An area of the switchable Bragg grating is configured to be activated to direct light to a platen. The platen is configured to reflect the light to a waveguide or to refract the light. The light reflected to the waveguide is guided to a light detector. By activating a number of the areas of the switchable Bragg grating and measuring the intensity of the light with a light detector, an image of an object contacting the platen may be formed.

Claims

1. An apparatus configured to scan an image, comprising:

a light source configured to provide light;

a light detector configured to detect the light;

a platen;

a waveguide;

a reflection grating;

a switchable Bragg grating; and

wherein an area of the switchable Bragg grating is configured to be activated to direct the light through the reflection grating and the waveguide to the platen, wherein the platen is configured to reflect the light via total internal reflection though the waveguide to the reflection grating or to refract the light, wherein the reflection grating is configured to reflect the light reflected from the platen to the waveguide, and wherein the waveguide is configured to guide the light to the light detector.

2. The apparatus of claim 1, wherein the apparatus is configured to scan a fingerprint image, a palm print image, or a hand print image.

3. The apparatus of claim 1, the light source comprising a laser.

4. The apparatus of claim 3, the laser comprising a laser configured to output infrared light.

5. The apparatus of claim 1, further comprising:

a plurality of transparent conducting oxide electrodes on a first surface and on a second surface of the switchable Bragg grating, each electrode on the first surface corresponding to an electrode on the second surface to form a plurality of pairs of electrodes.

6. The apparatus of claim 5, the transparent conducting oxide of the electrodes comprising indium tin oxide.

7. The apparatus of claim 5, wherein a pair of the pairs of electrodes is configured to generate an AC electric field.

8. The apparatus of claim 7, wherein the area of the switchable Bragg grating between the pair of electrodes is activated when an AC electric field is not generated between the pair of electrodes.

9. The apparatus of claim 1, further comprising:

a plurality of transparent conducting oxide electrodes on a first surface of the switchable Bragg grating; and

a layer of transparent conducting oxide electrode on a second surface of the switchable Bragg grating.

10. The apparatus of claim 1, further comprising:

a polarizer, the polarizer configured to polarize the light from the light source before the light enters the switchable Bragg grating.

11. The apparatus of claim 1, further comprising:

a first glass layer on a first side of the switchable Bragg grating; and

a second glass layer on a second side of the switchable Bragg grating.

12. The apparatus of claim 1, the light detector selected from the group consisting of a plurality of optical sensor arrays, a two-dimensional optical sensor array, and a linear optical sensor array.

13. The apparatus of claim 1, wherein the platen, the waveguide, the reflection grating, and the switchable Bragg grating are transparent, the apparatus further comprising:

a display, the display configured to be visible from a surface of the platen.

14. The apparatus of claim 13, wherein the display is further configured to display the image and an input selection.

15. An apparatus configured to scan an image and to receive input, comprising:

a light source configured to provide light;

a light detector configured to detect the light;

a platen;

a waveguide, the waveguide located under the platen;

a reflection grating, the reflection grating located under the waveguide;

a switchable Bragg grating, the switchable Bragg grating located under the reflection grating, wherein the platen, the waveguide, the reflection grating, and the switchable Bragg grating are transparent;

a display, the display configured to be visible to a user of the apparatus and to display an input selection, the display located under the switchable Bragg grating; and

wherein an area of the switchable Bragg grating is configured to be activated to direct the light through the reflection grating and the waveguide to the platen, wherein the platen is configured to reflect the light via total internal reflection though the waveguide to the reflection grating or to refract the light, wherein the reflection grating is configured to reflect the light reflected from the platen to the waveguide, and wherein the waveguide is configured to guide the light to the light detector.

16. A method of scanning an image, the method comprising:

(a) providing light to a switchable Bragg grating;

(b) activating an area of the switchable Bragg grating to direct the light through a reflection grating and a waveguide to a platen;

(c) reflecting the light from a surface of the platen via total internal reflection or refracting the light into an object contacting the surface of the platen, the reflected light directed through the waveguide to the reflection grating;

(d) reflecting the reflected light from the reflection grating to the waveguide; and

(e) guiding the reflected light with the waveguide to a detector.

17. The method of claim 16, further comprising:

transmitting the light through a polarizer before providing the light to the switchable Bragg grating.

18. The method of claim 16, wherein the light is provided by a laser, further comprising:

collimating and expanding the light from the laser before providing the light to the switchable Bragg grating.

19. The method of claim 16, wherein the switchable Bragg grating includes a plurality of areas configured to be activated, further comprising:

repeating steps (b)-(e) for each area of the switchable Bragg grating configured to be activated.

20. The method of claim 19, further comprising:

measuring an intensity of the light with the detector after each repetition of steps (b)-(e).

21. The method of claim 20, further comprising:

storing the measured intensity of the light after each repetition of steps (b)-(e); and

generating an image of the object contacting the platen using the measured intensities of the light.

22. The method of claim 16, further comprising:

displaying an input selection with a display, the display located under the platen, the waveguide, the reflection grating, and the switchable Bragg grating, the input selection being visible from the surface of the platen; and

detecting a selection of the input selection.

23. The method of claim 22, wherein the switchable Bragg grating includes a plurality of areas configured to be activated, wherein detecting a selection of the input selection includes:

repeating steps (b)-(e) for each area of the switchable Bragg grating configured to be activated;

measuring an intensity of the light with the detector after each repetition of steps (b)-(e); and

determining a region of the platen being contacted with a second object to select the input selection.

24. An apparatus configured to scan an image, comprising:

a light source configured to provide light;

a light detector configured to detect the light;

an object receiving surface;

a first plurality of switchable Bragg grating components arranged to form a first layer;

a second plurality of switchable Bragg grating components arranged to form a second layer; and

wherein areas of the first plurality of switchable Bragg grating components are configured to be activated to direct the light to the object receiving surface, wherein the object receiving surface is configured to reflect the light via total internal reflection though the first switchable Bragg grating components to activated areas of the second plurality of switchable Bragg grating components or to refract the light, and wherein the activated areas of the second switchable Bragg grating components are configured to direct the light towards the light detector.

25. The apparatus of claim 24, wherein each switchable Bragg grating component of the first plurality of switchable Bragg grating components and the second plurality of switchable Bragg grating components includes a waveguide wall on either side of a switchable Bragg grating material, the waveguide walls configured contain the light within the switchable Bragg grating material.

26. The apparatus of claim 24, further comprising:

a first plurality of transparent conducting oxide electrodes on a first surface and on a second surface of the first plurality of switchable Bragg grating components, each electrode on the first surface corresponding to an electrode on the second surface to form a first plurality of pairs of electrodes; and

a second plurality of transparent conducting oxide electrodes on a first surface and on a second surface of the second plurality of switchable Bragg grating components, each electrode on the first surface corresponding to an electrode on the second surface to form a second plurality of pairs of electrodes.

27. The apparatus of claim 24, wherein a pair of the first plurality of pairs of electrodes is configured to generate an AC electric field, and wherein a pair of the second plurality of pairs of electrodes is configured to generate an AC electric field.

28. The apparatus of claim 27, wherein the areas of the first plurality of switchable Bragg grating components between the pair of electrodes of the first plurality of pairs of electrodes is activated when an AC electric field is not generated between the pair of electrodes, and wherein the areas of the second plurality of switchable Bragg grating components between the pair of electrodes of the second plurality of pairs of electrodes is activated when an AC electric field is not generated between the pair of electrodes.

29. The apparatus of claim 24, wherein the object receiving surface, the first plurality of switchable Bragg grating components, and the second plurality of switchable Bragg grating components are transparent, the apparatus further comprising:

a display, the display configured to be visible from the object receiving surface, the display located under the object receiving surface, the first plurality of Bragg grating components, and the second plurality of Bragg grating components.

30. An apparatus configured to scan an image, comprising:

a light source configured to provide light;

a light detector configured to detect the light;

a platen;

a switchable Bragg grating;

a glass layer;

a waveguide;

a reflection grating; and

wherein an area of the switchable Bragg grating is configured to be activated such that light is taken out of total internal reflection with the switchable Bragg grating, wherein the platen is configured to reflect the light taken out of total internal refection with the switchable Bragg grating via total internal refection though the waveguide to the reflection grating, wherein the reflection grating is configured to reflect the light reflected from the platen to the waveguide, and wherein the waveguide is configured to guide the light to the light detector.

31. The apparatus of claim 30, further comprising:

a plurality of electrodes associated with the switchable Bragg grating, wherein the area of the switchable Bragg grating is activated when an electrode of the plurality of electrodes does not generate an AC electric field in the area of the switchable Bragg grating.

32. The apparatus of claim 31, wherein adjacent electrodes of the plurality of electrodes are configured to generate an AC electric field in areas of the switchable Bragg grating.

33. The apparatus of claim 30, the light source comprising a laser.

34. The apparatus of claim 30, the light detector selected from the group consisting of a plurality of optical sensor arrays, a two-dimensional optical sensor array, and a linear optical sensor array.

35. The apparatus of claim 30, wherein light is not taken out of total internal reflection with the switchable Bragg grating when the area of the switchable Bragg grating is activated and a ground reference object is in contact with the platen.