STEREOSCOPIC METHOD AND A DEVICE FOR IMPLEMENTATION THEREOF

• US 20100295930A1
• Filed: 04/15/2008
• Published: 11/25/2010
• Est. Priority Date: 04/20/2007
• Status: Active Grant

• Current Assignee: 3D Essence, LLC
• Original Assignee: Stunny 3D, LLC
• Inventors: Ezhov, Vasily Alexandrovich
• Granted Patent: US 7,929,066 B2
• Time in Patent Office: Days
• US Class Current: 348/58
• CPC Class Codes: G02B 30/25 using polarisation techniques
• CPC Class Codes: H04N 13/31 using parallax barriers
• CPC Class Codes: H04N 13/332 Displays for viewing with the aid of special glasses or head-mounted displays [HMD]
• CPC Class Codes: H04N 13/359 Switching between monoscopic and stereoscopic modes

Abstract

The invention relates to stereoscopic video equipment and can be used to design stereoscopic TV sets and monitors with a possibility to observe stereo images both glasses-free and with use of passive glasses while keeping a possibility to observe monoscopic images. These possibilities are provided in the method and in the device by means of a light flux elliptical polarization modulator with polarization modulation parameters determined by inverse trigonometric functions such as arctg, arcctg, arccos and arcsin (or their combinations) from algebraic relations between squared amplitudes of image temporal scanning signals, that permits with help of spatially-periodic polarization selector to obtain the images of the left and the right views in the left and right observation areas.

Claims

1-8. -8. (canceled)

9. A stereoscopic apparatus, comprising:

(A) a matrix polarization encoding device, that has M rows and N columns; and

(B) a polarization selector, that is arranged sequentially on the same optical axis as the matrix polarization encoding device;

wherein

(a) outputs of the selector are optically connected with left and right observation areas,

(b) a transfer characteristic for a mn-th element of the matrix polarization encoding device is determined by an inverse trigonometric function of a ratio of an algebraic relation of B_L^mn and B_R^mn, which are intensity values in a mn-th pixel of left and right views of a projected 3-dimensional image respectively, wherein m=1, 2, . . . , n=1, 2, . . . , N,

(c) the matrix polarization encoding device comprises a working medium that has mutually orthogonal directions of optical anisotropy for each pair of adjacent columns of the matrix polarization encoding device; and

(d) the polarization selector comprises a working medium comprising electrically addressable columns such that one of the following conditions is satisfied;

(i) an initial optical anisotropy state of the polarization selector is such that all the columns of the working medium of the polarization selector have the same optical anisotropy direction, and a subsequent optical anisotropy state of the polarization selector is such that each two adjacent columns of the working medium of the polarization selector have mutually orthogonal anisotropy directions;

or

(ii) an initial optical anisotropy state of the polarization selector is such that each two adjacent columns of the working medium of the polarization selector have mutually orthogonal anisotropy directions;

10. The apparatus of claim 9, further comprising a source of stereo video signal, an electronic functional module, wherein an output of the source of the stereo video signal is connected to an electrical input of the matrix polarization encoding device and to an electrical input of the electronic functional block;

and an output of the electronic functional block is connected to an electrical input of the polarization selector.

11. The apparatus of claim 9, wherein the matrix polarization encoding device is an electrically controlled matrix-addressable polarization encoding optical modulator, wherein a plane of the working medium of the polarization selector is located at a distance d from a plane of the working medium of the polarization encoding optical modulator, where d=Dp/b, and D is a distance from the polarization encoding optical modulator to the observation areas, p is a spatial period of the columns of the polarization encoding optical modulator and b is a distance between central points of adjacent observation areas.

12. The apparatus of claim 11, wherein the polarization encoding optical modulator comprises (a) a light intensity modulator and (b) an elliptical light polarization encoding modulator that comprises at least one working medium with a controlled polarization plane rotation;

wherein the polarization selector comprises a linear polarizer and wherein the light intensity modulator and the elliptical light polarization modulator are arranged sequentially so that a mn-th element of the light intensity modulator corresponds to a mn-th element of the elliptical light polarization modulator.

13. The apparatus of claim 11, wherein the polarization encoding optical modulator comprises sequentially arranged (a) a light intensity modulator and (b) an elliptical light polarization encoding modulator that comprises at least one working medium with a controlled birefringence and wherein the polarization selector comprises sequentially arranged (i) a phase decoder with a controlled birefringence and (ii) a linear polarizer, wherein the phase decoder is configured to create a phase shift between ordinary and extraordinary beams, which is equal to it in odd columns of the decoder and zero in even columns of the decoder.

14. The apparatus of claim 11, wherein the polarization encoding optical modulator comprises (a) a polarizer;

(b) a first phase and/or polarization optical modulator;

(b) a second phase and/or polarization optical modulator, wherein the polarizer, the first modulator and the second modulator are sequentially optically connected.

15. The apparatus of claim 14, wherein the first modulator is an optical modulator with a controlled polarization plane rotation, while the second modulator is a phase optical modulator with a controlled birefringence.

16. The apparatus of claim 14, wherein each of the first and second modulators is an optical modulator with a controlled polarization plane rotation.

17. The apparatus of claim 14, wherein each of the first and second modulators is an optical modulator with a controlled birefringence.

18. The apparatus of claim 14, wherein the polarizer is a linear or circular polarizer.

19. A stereoscopic method comprising:

(A) forming using a first device, that has M rows and N columns, a modulated light flux that has a complex modulation of intensity and polarization, such that a mn-th element of a cross section of the light flux presents jointly B_Lⁿⁿ and B_R^mn, which are intensity values in a mn-th pixel of left and right views of a projected 3-dimensional image, whereas polarization modulation parameters of the modulated light flux are set as an inverse trigonometric function of an algebraic relation between B_L^mn and B_R^mn, wherein m=1, 2, . . . , M, n=1, 2, . . . , N, are respectively numbers of rows and columns of the first device;

said forming comprises forming N groups of the modulated light flux, wherein an n-th group of the N groups, that is formed on an nth column of the first device, comprises a left and right partial light fluxes, which carry respectively information about an n-th column for the left and right views of the projected 3-dimensional image, whereas the polarization modulation parameters of the modulated light flux are mutually orthogonal (i) between the left and the right partial light fluxes for each of the N groups and (ii) between a partial light flux of the nth group and a partial flux of the (n+1) th group, which is adjacent to the nth group; and

(B) for each of the N groups, separating from the formed modulated light flux, using a second device, the left partial light flux and the right partial light flux and directing the left and right partial light fluxes to left and right observation areas respectively;

said second device comprises a decoder and a polarization filter;

wherein said separating comprises;

(i) decoding left and right views of the modulated light flux at a decoding plane of the decoder and

(ii) filtering the decoded light flux,

wherein the decoding plane of the decoder is divided into columns, each of which has a symmetry axis at an intersection of central axes of partial light fluxes with identical elliptical polarization modulation parameters, wherein said columns of the decoding plane of the decoder are such that one of the following two conditions is satisfied;

(a) a phase shift between each pair of adjacent columns in the decoding plane is π

/4 multiplied by a positive integer; and

(b) adjacent columns of the decoding plane produce mutually orthogonal changes of a polarization state.

20. The method of claim 19, wherein the first device is a matrix addressable polarization encoding optical modulator.

21. The method of claim 19, wherein:

(a) said forming the modulated light flux comprises encoding an elliptical polarization modulation in the modulated light flux using a matrix electrically addressable optical modulator with a controlled polarization plane rotation, which comprises N columns, such that a polarization plane rotation angle in each odd (2n−

1)-th column is

22. The method of claim 19, wherein:

(a) said forming the modulated light flux comprises encoding an elliptical polarization modulation in the modulated light flux using a matrix electrically addressable optical modulator with a controlled birefringence, which comprises N columns, such that a phase shift Δ

δ

<sup>m(2n−

1)</sup> between ordinary and extraordinary beams in each odd (2n−

1)-th column and a phase shift Δ

δ

^m(2n) between ordinary and extraordinary beams in each even column 2n-th column are set respectively to be arccos and arcsin functions of a ratio of an algebraic relation of B_L^mn and B_R^mn with addition of π

/4 multiplied by a non-negative integer;

wherein an intensity of light in an mn-th element of a cross section of the formed modulated light flux corresponds to a sum of B_L^mn and B_R^mn, and

(b) said decoding is performed using an electrically addressable by column optical modulator with a controlled birefringence by setting a value of a difference in a phase shift between ordinary and extraordinary beams for each pair of adjacent columns to be π

/4 multiplied by a positive integer.

23. The method of claim 19, wherein said forming the modulated light flux comprises encoding an elliptical polarization modulation of the modulated light flux using the following elements that are sequentially positioned and optically connected:

(i) a polarizer, (ii) a first matrix electrically addressable optical modulators with a controlled birefringence, that has M rows and N columns, and (iii) a second matrix electrically addressable optical modulators with a controlled birefringence, that has M rows and N columns, wherein a resulting phase shift Δ

δ

₁<sup>m(2n−

1)</sup>−

Δ

δ

₂<sup>m(2n−

1)</sup> between ordinary and extraordinary beams in each odd (2n−

1)-th column and a resulting phase shift Δ

δ

₁^m(2n)−

Δ

δ

₂^m(2n) between ordinary and extraordinary beams in each even column 2n-th column of both the first and the second optical modulators are set respectively to be arccos and arcsin functions of a ratio of an algebraic relation of B_L^mn and B_R^mn with addition of π

/4 multiplied by a non-negative integer.

24. The method of claim 19, wherein said forming the modulated light flux is performed using the following elements that are sequentially positioned and optically connected:

(i) a polarizer, (ii) a first matrix electrically addressable optical modulators with a controlled polarization plane rotation, that has M rows and N columns and (iii) a second matrix electrically addressable optical modulator with a controlled polarization plane rotation, that has M rows and N columns, wherein a resulting angle of polarization plane rotation φ

₁<sup>m(2n−

1)</sup>−

φ

₂<sup>m(2n−

1)</sup> in each odd (2n−

1)-th column and a resulting angle of polarization plane rotation φ

₁<sup>m(2n)−

φ</sup>

₂^m(2n) in each even column 2n-th column of both the first and the second optical modulators are set respectively to be

25. The method of claim 19, wherein said forming the modulated light flux is performed using the following elements that are sequentially positioned and optically connected:

(i) a polarizer, (ii) a first matrix electrically addressable optical modulators with a controlled polarization plane rotation, that has M rows and N columns and (iii) a second matrix electrically addressable optical modulators with a controlled birefringence, that has M rows and N columns.

26. The method of claim 19, wherein said decoding is performed using a controlled or static polarization filter that creates mutually orthogonal polarization states between adjacent columns of the decoding plane.

27. The method of claim 26, wherein said polarization filter is (a) a linear polarization filter that creates mutually orthogonal linear polarization states between adjacent columns of the decoding plane or (b) a circular polarization filter that creates mutually orthogonal circular polarization states between adjacent columns of the decoding plane.