Abstract:
Systems, methods, apparatus and devices for head mounted stereoscopic 3-D display devices using the tunable focus liquid crystal micro-lens array eye to produce eye accommodation information. A liquid crystal display panel displays stereoscopic images and uses tunable liquid crystal micro-lens array to change the diopter of the display pixels to provide eye accommodation information. The head mounted display device includes a planar display screen, planar tunable liquid crystal micro-lens array and planar black mask. The display device may optionally include a bias lens. In an embodiment, the display device also includes a backlight and a prism sheet for displaying the images on the display screen. The display screen, tunable liquid crystal micro-lens array, black mask and optional backlight and prism may be flat or curved.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to head mounted displays and, in particular, to apparatus, methods, systems and devices for head mounted stereoscopic 3-D display devices using the tunable focus liquid crystal micro-lens array eye to produce accommodation information, wherein the tunable liquid crystal micro-lens array changes the diopter of the display pixels to provide the eye accommodation information.  
       BACKGROUND AND PRIOR ART  
       [0002]     The perception of three dimensional images is a visual effect created by stereoscopy, visual accommodation, perspective (apparent size dependent on distance), occlusion (objects in front hide what is behind), atmospheric effects (objects in the distance appear hazy), shading, and so on. Images presented by planar displays, such as CRTs, LCDs, projection displays, laser scan displays, and others, provide visual clues of a three dimensional image using perspective, occlusion, shading, and atmospheric effects at a fixed visual focal length that determined by the distance between the display screen and the audience. Stereoscopic displays, such as 3-dimensional LCDs and 3-dimensional head mounted displays, provide spatially distinct images to each eye so that the stereoscopy is also included in the visual clues for the perception of three dimensional images.  
         [0003]     Although some 3-dimensional head mounted displays are superior to 3-dimensional LCDs in providing better stereoscopy images, the displayed images are still at a fixed visual focal length while the stereoscopy and visual accommodation are inherently related in the perception of a three dimensional image. Furthermore, because high power lenses are required to provide visible image on a screen adjacent to the eye, bulky configuration and heavy weight are the common problems in the optical system of conventional head mounted displays, especially when the field of view is increased.  FIG. 1  shows the schematic diagram of the optical system in such a prior art. According to U.S. Pat. No. 4,130,832 issued to Sher on Dec. 19, 1978, and U.S. Pat. No. 5,355,181 issued to Ashizaki et al on Oct. 11, 1994 and U.S. Publication No. 2004/0130783 A1 published on Jul. 8, 2004, inventions about 3-D head mounted displays using variable focal length elements to modulate scanning light beam provided a solution to relating visual accommodation with the stereoscopy.  
         [0004]     However, the high cost, complex configuration, high requirements of components arrangement accuracy are significant problems. According to prior art publications include Ren, Hongwen, Tunable microlens arrays using polymer network liquid crystal, Optics Communication, vol. 230 (2004), p. 267-271, and Lin, Yi-Hsin et al., Tunable-focus cylindrical liquid crystal lenses, Japanese Journal of Applied Physics, vol. 44 (2005), p. 243, and Ren, Hongwen, Tunable-focus flat liquid crystal spherical lens, Applied Physics Letter, vol. 84 (2004), p. 4789, several tunable focus liquid crystal lens were described.  
         [0005]     Therefore, a need exists for a low cost method and device of head mounted display providing stereoscopy images with visual accommodation and the presented device is slim and light weight.  
       SUMMARY OF THE INVENTION  
       [0006]     A primary objective is to provide apparatus, methods, systems and devices for producing eye accommodation information using the tunable focus liquid crystal micro-lens array for head mounted stereoscopic 3-dimensional displays.  
         [0007]     A secondary objective is to provide s to provide apparatus, methods, systems and devices using tunable liquid crystal micro-lens array to change the diopter of the display pixel to provide eye accommodation information.  
         [0008]     A third objective is to provide apparatus, methods, systems and devices for producing light weight head mounted visual displays with eye accommodation information.  
         [0009]     A fourth objective is to provide apparatus, methods, systems and devices for a compact size head mounted visual displays for displaying three dimensional images with visual accommodation.  
         [0010]     A fifth objective is to provide apparatus, methods, systems and devices for the head mounted visual display to display three dimensional images with visual accommodation with a high resolution.  
         [0011]     A sixth objective is to provide apparatus, methods, systems and devices for head mounted visual displays with large field of view.  
         [0012]     A seventh objective is to provide apparatus, methods, systems and devices for displaying three dimensional images with visual accommodation at a low cost.  
         [0013]     A first preferred embodiment of the invention is to provide an improved method and device for producing eye accommodation information by alternating the diopter of display pixel using the tunable focus liquid crystal micro-lens array wherein the head mounted stereoscopic 3-D display devices. In a first embodiment, the display device comprises planar display screen, planar tunable liquid crystal micro-lens array, planar black mask, and bias lens.  
         [0014]     In a second embodiment of the invention, the display device comprises planar display screen, planar tunable liquid crystal micro-lens array, planar black mask, and bias micro-lens array.  
         [0015]     In a third embodiment of the invention, the display device comprises curved display screen, curved tunable liquid crystal micro-lens array, and curved black mask.  
         [0016]     Further objectives, features, and advantages of this invention will be apparent from the following detailed descriptions of the presently preferred embodiments that are illustrated schematically in the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0017]      FIG. 1  is a schematic diagram showing an example of a prior art head mounted 3-D display device with fixed focus length.  
         [0018]      FIG. 2  is a schematic diagram showing an example of a head mounted 3-dimensional display device comprising planar display screen and tunable focus liquid crystal micro-lens array and bias lens according to a first embodiment of the present invention.  
         [0019]      FIG. 3   a  is a schematic diagram showing an example of the configuration of the optical components according to the first embodiment.  
         [0020]      FIG. 3   b  shows an example of a virtual image displayed on the planar emissive display screen being provided to the user as a retinal image using the configuration shown in  FIG. 3   a.    
         [0021]      FIG. 4   a  is a schematic diagram showing another example of the configuration of the optical components according to the first embodiment.  
         [0022]      FIG. 4   b  shows an example of a virtual image displayed on the planar transmissive display screen being provided to the user as a retinal image using the configuration shown in  FIG. 4   a.    
         [0023]      FIG. 5   a  is a schematic diagram showing another example of the configuration of the optical components according to the first embodiment.  
         [0024]      FIG. 5   b  shows an example of a virtual image displayed on the planar reflective display screen being provided to the user as a retinal image using the configuration shown in  FIG. 5   a.    
         [0025]      FIG. 6   a  is a schematic diagram showing another example of the configuration of the optical components according to the first embodiment.  
         [0026]      FIG. 6   b  shows another example of a virtual image displayed on the planar reflective display screen being provided to the user as a retinal image using the configuration shown in  FIG. 6   a.    
         [0027]      FIG. 6   c  is a schematic diagram showing another example of the configuration of the optical components according to the first embodiment.  
         [0028]      FIG. 6   d  shows another example of a virtual image displayed on the planar reflective display screen being provided to the user as a retinal image using the configuration shown in  FIG. 6   c.    
         [0029]      FIG. 7  is a schematic diagram showing an example of a head mounted 3-dimensional display device having a planar display screen, tunable focus liquid crystal micro-lens array and bias micro-lens array according to a second embodiment of the present invention.  
         [0030]      FIG. 8   a  is a schematic diagram showing an example of the configuration of the optical components according to a second embodiment.  
         [0031]      FIG. 8   b  shows an example of a virtual image displayed on the planar emissive display screen being provided to the user as a retinal image using the configuration shown in  FIG. 8   a.    
         [0032]      FIG. 9   a  is a schematic diagram showing another example of the configuration of the optical components according to the second embodiment.  
         [0033]      FIG. 9   b  shows an example of a virtual image displayed on the planar transmissive display screen being provided to the user as a retinal image using the configuration shown in  FIG. 9   a.    
         [0034]      FIG. 10   a  is a schematic diagram showing another example of the configuration of the optical components according to the second embodiment.  
         [0035]      FIG. 10   b  shows an example of a virtual image displayed on the planar reflective display screen being provided to the user as a retinal image using the configuration shown in  FIG. 10   a.    
         [0036]      FIG. 11   a  is a schematic diagram showing another example of the configuration of the optical components according to the second embodiment.  
         [0037]      FIG. 11   b  shows another example of a virtual image displayed on the planar reflective display screen being provided to the user as a retinal image using the configuration shown in  FIG. 11   a.    
         [0038]      FIG. 12  is a schematic diagram showing an example of a head mounted 3-dimensional display device comprising curved display screen and tunable focus liquid crystal micro-lens array according to a third embodiment.  
         [0039]      FIG. 13   a  is a schematic diagram showing an example of the configuration of the optical components according to the third embodiment.  
         [0040]      FIG. 13   b  shows an example of a virtual image displayed on the curved emissive display screen being provided to the user as a retinal image using the configuration shown in  FIG. 13   a.    
         [0041]      FIG. 14   a  is a schematic diagram showing another example of the configuration of the optical components according to the third embodiment.  
         [0042]      FIG. 14   b  shows an example of a virtual image displayed on the curved transmissive display screen being provided to the user as a retinal image using the configuration shown in  FIG. 14   a.    
         [0043]      FIG. 15   a  is a schematic diagram showing another example of the configuration of the optical components according to the third embodiment.  
         [0044]      FIG. 15   b  shows an example of a virtual image displayed on the curved reflective display screen being provided to the user as a retinal image using the configuration shown in  FIG. 15   a.    
         [0045]      FIG. 16   a  is a schematic diagram showing another example of the configuration of the optical components according to the third embodiment.  
         [0046]      FIG. 16   b  shows another example of a virtual image displayed on the curved reflective display screen being provided to the user as a retinal image using the configuration shown in  FIG. 16   b.    
         [0047]      FIG. 16   c  is a schematic diagram showing another example of the configuration of the optical components according to the third embodiment.  
         [0048]      FIG. 16   d  shows another example of a virtual image displayed on the curved reflective display screen being provided to the user as a retinal image using the configuration shown in  FIG. 16   c.   
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0049]     Before explaining the disclosed embodiments of the present invention in detail it is to be understood that the invention is not limited in its application to the details of the particular arrangements shown since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation.  
         [0050]     The following is a list of the designators used in the drawings and the detailed specification to identify components, wherein like components assigned like designators:  1011  display screens  25   205  eyes  102  image lenses  206  liquid crystal micro-lens  103  eyes  301  planar emissive LC display screen  201  planar display screens  302  planar black mask  202  planar black masks  303  planar tunable focus LC lens array  203  planar tunable focus LC lens arrays  30   304  bias lens  204  planar bias lens  306  liquid crystal micro-lens  308  liquid crystal micro-lens  25   812  virtual object of display pixel  2   311  virtual object of display pixel  1   813  retinal image of the display pixel I  312  virtual object of display pixel  2   814  retinal image of the display pixel  2   313  retinal image of the display pixel  1   815  eye  314  retinal image of the display pixel  2   901  planar transmissive LC display  315  eye  30  screen  401  planar transmissive LC display  1001  planar reflective LC display screen screen  1101  image projector  501  planar reflective LC display screen  1102  planar reflective LC display screen  601  image projector  1201  curved display screens  602  planar reflective display screen  35   1202  curved black masks  701  planar display screens  1203  curved tunable focus LC lens  702  planar tunable focus LC lens arrays arrays  703  planar black masks  1205  eye  704  bias micro-lens arrays  1206  liquid crystal micro-lens  706  liquid crystal micro-lens  40   1301  curved emissive LC display screen  708  bias lens  1302  curved black mask  801  planar emissive LC display screen  1303  curved tunable focus LC lens array  802  planar tunable focus LC lens array  1306  liquid crystal micro-lens  803  planar black mask  1311  virtual object of display pixel  1   804  bias micro-lens array  45   1312  virtual object of display pixel  2   806  liquid crystal micro-lens  1313  retinal image of the display pixel  1   808  bias micro-lens  1314  retinal image of the display pixel  2   811  virtual object of display pixel  1   1315  eye  1401  curved transmissive LC display  1501  curved reflective LC display screen screen  1601  image projector  5   1602  curved reflective display screen  
         [0051]     The method, system apparatus and device of the present invention provides a new device structure for producing eye accommodation information using a tunable focus liquid crystal micro-lens array within a head mounted display devices.  
         [0052]      FIG. 2  shows an example of the configuration of the tunable focus liquid crystal micro-lens arrays for use in head mounted display devices of the presented invention. The head mounted display includes, for each of the left eye and the right eye, planar display screen  201 , black mask  202 , tunable focus liquid crystal micro-lens array  203  and a bias lens  204 . Planar display screens  201  display the stereoscopic images that are seen by the eyes  205  of the viewer. The planar display screens  201  can be emissive displays, such as OLEDs, transmissive displays, such as transmissive liquid crystal displays, reflective displays, such as reflective liquid crystal displays, or an alternative planar display.  
         [0053]     The tunable focus liquid crystal micro-lens arrays  203  are disposed in front of each display screen  201  between the display screen  201  and the corresponding eye  205 . The individual liquid crystal lenses  206  of the tunable focus liquid crystal micro-lens arrays  203  are aligned with the display pixels of the display screen  201 . Black masks  202  are disposed adjacent to the tunable focus liquid crystal micro-lens arrays  203  and bias lens  204 . The black masks  202  have apertures that are aligned with the individual liquid crystal lenses  206  so that only the light from the display screens passes through the liquid crystal lenses  206 . While the black masks  202  are shown between the display screen  201  and the liquid crystal micro-lens arrays  203 , the black mask  202  can be disposed on either side or on both sides of the liquid crystal micro-lens arrays  203 .  
         [0054]     When control signals are applied, the liquid crystal micro-lenses of the tunable focus liquid crystal micro-lens arrays  203  alternates the convergence of the light emitting from the corresponding display pixels of the planar display screens  201 . Thus, the viewer&#39;s eye acclimates to variations in the diopter of the display pixels to enhance the experience of three dimensional visual effects. The bias lenses  204  are disposed between the tunable focus liquid crystal micro-lens arrays  203  and the corresponding eye  205 . The bias lenses  204  converges the light into the pupil of the adjacent eye  205  so that all portions of the displayed image visible even though the field of view is large and/or the viewer moves the eye  205 .  
         [0055]     A more specific example of the first embodiment is shown in  FIGS. 3   a  and  3   b .  FIG. 3   a  is a schematic diagram showing an example of a configuration of the tunable focus liquid crystal and  FIG. 3   b  shows an example of an image displayed on the planar emissive display screen  301  being transmitted to the viewer&#39;s eye using the configuration shown in  FIG. 3   a . For purpose of illustration and discussion, the device is described for one eye although there is a duplicate device for the other eye.  
         [0056]     As shown in  FIG. 3   b , the head mounted stereoscopic 3-dimensional display devices comprise planar emissive display screens  301 , planar black masks  302 , planar tunable focus liquid crystal micro-lens arrays  303  and bias lenses  304  as previously described in regard to  FIG. 2 . The each planar emissive display screen  301  displays one of the stereoscopic images to be seen by the corresponding eye of the viewer.  
         [0057]     The tunable focus liquid crystal micro-lens array  303  is disposed in front of the display screen between the planar emissive display screen  301  and the viewer&#39;s eye  315 . The individual liquid crystal micro-lenses  306  of the tunable focus liquid crystal micro-lens array  303  are aligned with the display pixels of the planar emissive liquid crystal display screen  301 . Black mask  302  is disposed adjacent the tunable focus liquid crystal micro-lens array  303  so that only light from the display screens  301  passes through the liquid crystal micro-lenses  306  as shown in  FIG. 3   b . As previously described, the black mask  302  can be disposed on either side or on both sides of the liquid crystal micro-lens array  303 .  
         [0058]     Upon application of control signals, the liquid crystal micro-lenses  306  of the tunable focus liquid crystal micro-lens array  303  alternates, from pixel  1  to pixel  2  and vice versa, for convergence of light emitting from the corresponding display pixels of the planar emissive liquid crystal display screen  301 . For example, a virtual object  311  of display pixel  1  passes through the liquid crystal micro micro-lens  306  of the tunable focus liquid crystal micro-lens array  303  to the bias lens  304  which converges the virtual image  311  onto the pupil of the eye to provide retinal image  313  of display pixel  1 . Similarly, virtual object  312  of display pixel  2  passes through liquid crystal micro-lens  308  to bias lens  304  which converges the virtual image  312  on the eye  315  to provide the retinal image  314  of pixel  2 . Thus, the eye  315  of the viewer acclimates itself to the variations in the diopter of the display pixels to enhance the experience of three dimensional visual effects. In this example, the bias lens  304  is configured as shown in  FIG. 3   a  to converge light into the pupils so that approximately all portions of the displayed image are visible even though the field of view is large and/or the viewer moves the eye.  
         [0059]     Another example is shown in  FIGS. 4   a  and  4   b .  FIG. 4   a  shows the configuration of the optical components and  FIG. 4   b  shows a virtual image  311 ,  312  from the transmissive display device  401  being transmitted to the user as retinal images  313 ,  314  using the optical configuration shown in  FIG. 4   a . In this example, the head mounted stereoscopic 3-dimensional display devices includes a planar transmissive liquid crystal display screens  401 .  
         [0060]     Operationally, one of the stereoscopic images is shown on the planar transmissive liquid crystal display panel  401 . As described in the previous example, the tunable focus liquid crystal micro-lens array  303  is disposed between the display screen  401  and the eye  315 . the individual liquid crystal lenses  306  and  308  in the tunable focus liquid crystal micro-lens array  303  are aligned with the display pixels of the planar transmissive liquid crystal display panel  401 . Black mask  302  with apertures corresponding to the liquid crystal lenses  306  and  308  is disposed adjacent to the tunable focus liquid crystal micro-lens array  303  so that only the light from the display screen pixel  1  and pixel  2 , alternately, pass through the liquid crystal micro-lenses  106  as shown in  FIG. 4   b . As in the previous example, the black mask  302  can be disposed on either side or on both sides of the liquid crystal micro-lens array  303 .  
         [0061]     Another example is shown in  FIGS. 5   a  and  5   b . In this example the head mounted stereoscopic 3-D display devices includes planar reflective liquid crystal display screens  501  in combination with the planar black mask  302 , planar tunable focus liquid crystal micro-lens arrays  303  and bias lenses  304  as previously described. In this alternative example, the light reflected from the planar reflective liquid crystal display screen  501  is already collimated. One of the stereoscopic images is shown on the planar reflective liquid crystal display panel  501 . The tunable focus liquid crystal micro-lens array  303  is disposed between the planar reflective display screen  501  and the eye  315 . As previously described, the individual liquid crystal lenses  306  of the tunable focus liquid crystal micro-lens array  303  are aligned with the display pixels of the planar reflective liquid crystal display panel  501 . Black mask  302  is disposed adjacent to, and aligned with, the tunable focus liquid crystal micro-lens array  303  so that only light from the display screen passes through the liquid crystal micro-lenses  303  as shown in  FIG. 5   b.    
         [0062]     Another example is shown in  FIGS. 6   a  and  6   b . In this example the head mounted stereoscopic 3-D display devices includes image projector  601 , planar reflective display screens  602  in combination with the planar black mask  302 , planar tunable focus liquid crystal micro-lens arrays  303  and bias lenses  304  as previously described. One of the stereoscopic images is produced from the image projector  601  and reflected from the planar reflective display screen  602 . In this alternative example, the light produced from the image projector is already collimated. The tunable focus liquid crystal micro-lens array  303  is disposed between the planar reflective display screen  602  and the eye  315 . As previously described, the individual liquid crystal micro-lenses  306  of the tunable focus liquid crystal micro-lens array  303  are aligned with the display pixels of the planar reflective display panel  602 . Black mask  302  is disposed adjacent to, and aligned with, the tunable focus liquid crystal micro-lens array  303  so that only light from the display screen passes through the liquid crystal micro-lenses  303  as shown in  FIG. 6   b.    
         [0063]     An alternate disposition of the tunable focus liquid crystal micro-lens array  303  for this example is illustrated in  FIGS. 6   c  and  6   d . The tunable focus liquid crystal micro-lens array  303  is disposed between the image projector  601  and the planar reflective display screen  602 . Black mask  302  is disposed adjacent to, and aligned with, the tunable focus liquid crystal micro-lens array  303  so that only light from the display screen passes through the liquid crystal micro-lenses  303  as shown in  FIG. 6   b.    
         [0064]      FIG. 7  show an alternative example of a tunable focus liquid crystal micro-lens array configuration of the present invention. In this example, the head mounted stereoscopic 3-D display devices includes planar display screens  701 , planar black masks  703 , planar tunable focus liquid crystal micro-lens arrays  702  and bias micro-lens arrays  704 . Referring back to  FIG. 2 , since the display screens of the head mounted displays are arranged at a distance very close to the eyes of the viewer, the power of the bias lenses  204  is large enough to cover the planar tunable focus liquid crystal lens array  203 .  
         [0065]     To further reduce the weight and the thickness of the head mounted display devices, the bias lenses in  FIG. 2  are replaced by the bias micro-lens arrays  704  having individual bias lenses  708  that are aligned with the liquid crystal micro-lenses  706  of the planar tunable focus liquid crystal micro-lens arrays  702 . In the example shown in  FIG. 7 , the planar black masks  703  is located between the bias micro-lens arrays  704  and the planar tunable focus liquid crystal micro-lens arrays  702  although the planar black mask  703  can alternatively be located on the opposite side or on both sides of the planar tunable focus liquid crystal micro-lens arrays  702 .  
         [0066]     The planar display screens  701  can be emissive displays, such as OLEDs, transmissive displays, such as transmissive liquid crystal displays, reflective displays, such as reflective liquid crystal displays, or other planar displays. The tunable focus liquid crystal micro-lens arrays  702  are disposed in front of each display screen between the display screen and the eyes  315 . The liquid crystal micro-lenses  706  of the tunable focus liquid crystal micro-lens arrays  702  and bias lenses  708  of the bias micro-lens arrays  704  are aligned with one another and with the display pixels of the display screen  701 .  
         [0067]      FIGS. 8   a  and  8   b  show another example of the present invention using the configuration shown in  FIG. 7 .  FIG. 8   a  is a schematic diagram showing another example of the configuration of the optical components and  FIG. 8   b  shows an example of a virtual image  811  and  812  displayed on the planar emissive display screen as pixels  1  and  2  being transmitted to the viewer&#39;s eye  815  as a retinal image  813  and  814 , respectively, using the configuration shown in  FIG. 8   a . In this example the planar display screens are planar emissive liquid crystal display screens  801 .  
         [0068]     As described in regard to  FIG. 3 , when the planar display screen is an emissive display screen  801 , head mounted stereoscopic 3-D display devices includes planar emissive liquid crystal display screen  801 , planar black masks  803 , planar tunable focus liquid crystal micro-lens arrays  802  and bias micro-lens arrays  804 . The bias micro-lenses  808  of the bias micro-lens array  804  are aligned with the liquid crystal micro-lenses  806  of the tunable focus liquid crystal micro-lens array  802 . Operationally, the device reflects images from the planar emissive liquid crystal display  801  screen in the same manner as described in regard to  FIG. 3   b.    
         [0069]     Another example of the present invention is shown in  FIGS. 9   a  and  9   b . Like the head mounted stereoscopic 3-D display device previously described in regard to  FIG. 4   b , the planar display screen is alternatively a planar transmissive display screen  901 . The images are displayed on the planar transmissive liquid crystal display panel  901  are transmitted to the viewer in the same manner described in regard to  FIG. 4   b.    
         [0070]      FIGS. 10   a  and  10   b  show yet another example of the present invention. In this embodiment, the planar display screen is a planar reflective liquid crystal display screen  1001  wherein the light reflected from the display screen  1001  is already collimated as described in regard to the example shown in  FIG. 5   b . The difference between this example and the example shown in  FIG. 5   b  is plural bias micro-lenses  808  in the bias micro-lens array  804  which are aligned with the plural liquid crystal micro-lenses  806  in the tunable focus liquid crystal micro-lens array  802 .  
         [0071]      FIGS. 11   a  and  11   b  show another example of the present invention. In this embodiment, the planar display screen is a planar reflective screen  1102  wherein the light produced from the image projector  1101  is reflected from the display screen  1102 . The tunable focus liquid crystal micro-lens array  802  is disposed between the planar reflective display screen  1102  and the eye  815 . The difference between this example and the example shown in  FIG. 6 ( b ) is plural bias micro-lenses  808  in the bias micro-lens array  804  which are aligned with the plural liquid crystal lenses  806  in the tunable focus liquid crystal micro-lens array  802 .  
         [0072]      FIG. 12  shows yet another example of the of the tunable focus liquid crystal micro-lens arrays components and their placement with respect to the viewer&#39;s eye  1205 . In this example, the head mounted stereoscopic 3-D display device includes curved display screens  1201 , curved black masks  1202  and curved tunable focus liquid crystal micro-lens arrays  1203 . Another difference between the configurations shown in  FIGS. 2 and 8  and the configuration shown in  FIG. 12 , the device does not include a bias lens or a bias micro-lens arrays. The curved display screens  1201  can be emissive displays, such as OLEDs, transmissive displays, such as transmissive liquid crystal displays, reflective displays, or other curved displays.  
         [0073]     The tunable focus liquid crystal micro-lens arrays  1203  are disposed between the display screens  1201  and the viewer&#39;s eye  1205 . The plural liquid crystal micro-lenses  1206  of the tunable focus liquid crystal micro-lens arrays  1203  are aligned with the display pixels of the display screen  1201  so that the convergent light passes through the liquid crystal micro-lenses  1206  as described in the previous examples. Curved black masks  1202  are disposed adjacent to the curved tunable focus liquid crystal micro-lens arrays  1203  so that the light from the display screens only passes through the liquid crystal micro-lenses  1203 . As with the previous examples, the curved black masks  1202  can be disposed on either side or both sides of the curved tunable focus liquid crystal micro-lens arrays  1203 .  
         [0074]     A more specific example is shown in  FIGS. 13   a  and  13   b .  FIG. 13   a  shows the optical components and their placement with respect to one another and  FIG. 13   b  shows the focusing of the virtual images  1311  and  1312  corresponding to a first and second display pixel to the viewer&#39;s eye  1315  to produce retinal images  1313  and  1314 , respectively. The optical components shown in  FIG. 13   a  are curved as described for the example shown in  FIG. 12  with an alternative number of apertures in the curved black masks  1302  and the liquid crystal lenses  1306  of the curved tunable focus liquid crystal micro-lens arrays  1303 . As in the previous embodiments, the curved black masks  1302  can be disposed on either side or on both sides of the curved tunable focus liquid crystal micro-lens arrays  1303 .  
         [0075]     As previously described, when control signals are applied, the liquid crystal lenses  1306  of the tunable focus liquid crystal micro-lens array  1303  alternate the convergence of the light emitting from the corresponding display pixels of the curved emissive display screen  1301  as shown in  FIG. 13   b  so that the corresponding eye acclimates itself to the variations in the diopter of display pixels to enhance the experience of three dimensional visual effects as described in regard to  FIGS. 3   b  and  8   b.    
         [0076]     In the example shown in  FIGS. 14   a  and  14   b , the head mounted stereoscopic 3-D display devices includes the curved planar transmissive display screen  1401 , curved black mask  1202  and curved tunable focus liquid crystal lens array  1203  as shown in  FIGS. 12   a  and  12   b . However, in this example, like the examples shown in  FIGS. 4   b  and  9   b , the planar transmissive display screen is a curved transmissive display screen  1401  The stereoscopic images are shown on the curved transmissive liquid crystal display panel  1401 .  
         [0077]     As previously described, when control signals are applied, the liquid crystal micro-lenses of the tunable focus liquid crystal micro-lens array  1203  alternate the convergence of the light emitting from the corresponding display pixels of the planar transmissive liquid crystal display panel  1401  as shown in  FIG. 14   b  to change the diopter of display pixels so that the eye accommodation information is provided.  
         [0078]      FIGS. 15   a  and  15   b  show yet another example of the present invention. In this embodiment, the display screen is a curved reflective liquid crystal display screen  1501  wherein the light reflected from the curved reflective liquid crystal display screen  1501  is already collimated as described in regard to the example shown in  FIGS. 5   b  and  10   b.    
         [0079]      FIGS. 16   a  and  16   b  show yet another example of the present invention. In this embodiment, the light produced from the image projector  1601  is reflected by the curved reflective display screen  1602 . The curved tunable focus liquid crystal micro-lens array  1303  is disposed between the curved reflective display screen  1602  and the eye  1315  as described in regard to the example shown in  FIGS. 6   b  and  11   b .  FIGS. 16   c  and  16   d  show an alternate arrangement of the curved tunable focus liquid crystal micro-lens array  1303  and the curved black mask  1302 . The curved tunable focus liquid crystal micro-lens array  1303  is disposed between the image projector  1601  and the curved reflective display screen  1602  in the same configurations as described in regard to the example shown in  FIG. 6   d . As previously described, the difference between the configuration shown in  FIG. 6   d  and  FIG. 16   d , is the bias micro-lens array shown in  FIG. 6   d . While there is a difference in the configuration, the operation of the head mounted display shown in  FIG. 16   d  is the same as described in regard to  FIG. 6   d.    
         [0080]     While the invention has been described, disclosed, illustrated and shown in various terms of certain embodiments or modifications which it has presumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.