Apparatus for displaying a hologram

Abstract

An apparatus for displaying a hologram comprises: a hologram display panel that represents light having the hologram images to an observer; a detecting camera that decides a position of the observer; a deflector that forms a prism pattern to refract the light corresponding to the detected position of the observer; and a deflector driver that supplies a driving voltage corresponding to a inclined angle for forming the prism pattern, wherein the deflector includes: a plurality of first electrodes running to a first direction and divided into a plurality of electrode groups; a plurality of connection electrodes running to a second direction crossing with the first direction, and connecting same numbered first electrodes of the electrode groups, wherein each end of the connection electrodes forms a pad portion; and a second electrode facing to the plurality of the first electrodes with a liquid crystal cell therebetween.

Claims

1. An apparatus for displaying hologram images, comprising: a hologram display panel that represents light having the hologram images to an observer; a detecting camera configured to acquire images of the observer; a light path deflecting panel, including: a plurality of first electrodes extending in a first direction and divided into a plurality of first electrode groups in a display area of the light path deflecting panel, each first electrode group corresponding to a pitch distance of the light path deflecting panel and including a same number of first electrodes; a plurality of connection electrodes extending in a second direction crossing with the first direction in a non-display area of the light path deflecting panel, wherein one end of each of the connection electrodes forms a pad portion at one end side of a substrate, each of the connection electrodes connected to first ends of corresponding first electrodes of each of the plurality of first electrode groups; a plurality of connection lines extending in a second direction crossing with the first direction in a non-display area of the light path deflecting panel, wherein another end of each of the connection electrodes forms a pad portion at another end side of the substrate, each of the connection lines connected to second ends of corresponding first electrodes of each of the plurality of first electrode groups; and a second electrode facing the plurality of the first electrodes with a liquid crystal cell therebetween; wherein the plurality of connection lines is positioned in the non-display area of the light path deflecting panel, wherein the second end is opposite to the first end of the first electrodes in the non-display area of the light path deflecting panel, and wherein one first electrode of the first electrode groups, one connection line of the connection line groups and one connection electrode of the connection electrodes groups are connected in a closed loop shape.

2. The apparatus according to the claim 1, wherein the first electrodes include a transparent conductive material and the connection electrodes include metal material.

3. The apparatus according to the claim 2, wherein the light path deflecting panel further includes: a first substrate and a second substrate facing to each other with the liquid crystal cell therebetween, wherein the first electrodes are disposed on the first substrate, a first insulating layer is deposited on the first electrodes, the connection electrodes are disposed on the first insulating layer, and a second insulating layer is deposited over the connection electrodes, wherein the second electrode is disposed on the second substrate, and a third insulating layer is deposited on the second electrode, and wherein the light path deflecting panel has the display area and the non-display area surrounding the display area, and the connection electrodes are connected to the corresponding first electrodes through contact holes that penetrate the first insulating layer and expose portions of the first electrodes, at the non-display area.

4. The apparatus of claim 1, wherein a driving voltage applied each of the plurality of connection electrodes is selected between monotonically increasing or monotonically decreasing with connection electrode number to yield a ramp voltage pattern on the first connection electrodes within each pitch distance of the light path deflecting panel to produce refraction and zero voltage for no refraction.

5. The apparatus of claim 1, further comprising a light path deflecting panel driver that includes a look-up table having a plurality of groups of driving voltages, each of the groups of driving voltages including driving voltages to be supplied to the light path deflecting panel at corresponding calculated positions of the observer.

6. The apparatus of claim 1, wherein adjacent first electrodes are spaced apart from one another by a distance of less than 2 micrometers.

7. The apparatus of claim 1, wherein the plurality of connection electrodes and the plurality of connection lines are positioned in the non-display area of the light path deflecting panel.

8. The apparatus of claim 3, wherein each of the first insulating layer and the second insulating layer includes at least one of silicon nitride or silicon oxide.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

(2) FIG. 1 is the structural drawing illustrating the digital holography image/video display device according to the related art.

(3) FIG. 2 is a structural drawing illustrating a hologram system according to an exemplary embodiment of the present disclosure.

(4) FIGS. 3 and 4 are drawings explaining the principle of the light refraction by the prism pattern formed at the light path deflecting panel.

(5) FIG. 5 is a plan view illustrating the array structure of the first electrodes of the light path deflecting panel.

(6) FIG. 6 is a cross sectional view along the cutting line VI-VI of FIG. 5.

(7) FIG. 7 is a cross sectional view along the cutting line VII-VII and VIII-VIII of FIG. 5.

(8) FIG. 8 is a drawing explaining one method for driving the hologram display according to the present disclosure.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

(9) Referring to attached figures, preferred embodiments of the present disclosure will be described. Like reference numerals designate like elements throughout the detailed description. However, the present disclosure is not restricted by these embodiments but can be applied to various changes or modifications without changing the technical spirit. In the following embodiments, the names of the elements are selected for ease of explanation and may be different from actual names.

(10) FIG. 2 is a structural drawing illustrating a hologram system according to an exemplary embodiment of the present disclosure. Referring to FIG. 2, a hologram system according to the present disclosure comprises a hologram display panel 10, a light path deflecting panel 30, a display panel driver 50, a deflecting panel driver 60, a controller 80 and detecting camera 90.

(11) In this embodiment, the hologram display panel 10 may have the similar structure as shown in FIG. 1. For example, the hologram display panel 10 may be made of the transmittive liquid crystal display panel. The hologram display panel 10 may represent the interference fringe patterns by receiving the data relating to the interference fringe patterns from a computer or video processor (not shown in figures). Then, as the collimated light from the laser source disposed at one side of the hologram display panel 10 is radiated to the hologram display panel 10, the hologram images may be displayed the other side from the hologram display panel 10.

(12) On the path of the collimated light is going (+Z axis of FIG. 2), the light path deflecting panel (or deflector) 30 may be disposed nest to the hologram display panel 10. The deflector 30 can transmit the light from the hologram display panel 10 as is. Or, it can refract the light to the left side () or to the right side (+) (on the X axis of FIG. 2). Therefore, the hologram images reproduced at distance apart from the hologram display panel 10 may be represented at the left/right shifted position on the horizontal axis (X axis) by the deflector 30.

(13) The hologram display panel driver 50 includes a gate driver and a data driver. The data driver receives the hologram data DATA from the controller 80 and then converts the hologram data DATA to the positive/negative analogue data voltages using the positive/negative gamma compensation voltage supplied from the gamma voltage generator (not shown). The data driver supplies the positive/negative analogue data voltages to the data lines of the hologram display panel 10. The gate driver supplies the gate pulse (or scan pulse) synchronized with the data voltage to the gate lines of the hologram display panel 10 sequentially, by the controlling signal from the controller 80.

(14) The deflector driver 60 supplies the driving voltages for controlling the deflector 30 to the deflector 30. The driving voltages can decide the inclined amount of the prism pattern formed at the deflector 30 so that the hologram images can be radiated to a proper position of the user/observer. The driving voltages may be groups of voltages which are linearly increased or decreased for linearly controlling the alignment of the liquid crystal molecules disposed in the liquid crystal cell.

(15) The controller 80 may control the hologram display panel driver 50 for driving the hologram display panel 10. The controller 80 supplies the gate control signal GCS to the gate driver and it supplies the data control signal DCS and the hologram data DATA to the data driver. The gate control signal GCS may include a gate start pulse, a gate shift clock, a gate output enable and so on. The data control signal DCS may include a source start pulse, a source sampling clock, a source output enable, a polarity signal and so on.

(16) The detecting camera 90 takes the pictures of the observer and sends them to the controller 80. The controller 80 analyses the images of the pictures and calculates the position of the observer. The controller 80 compares the detected position of the observer with the reference position to decide the relative position of the observer from the reference position. According to this relative position of the observer, the controller 80 controls the deflector driver 60 to form the prism pattern having proper inclined angle at the deflector 30. For the case that the observer moves to a horizontal direction from the reference position, the deflector driver 60 makes the deflector 30 form a prism pattern for refracting the light to the horizontal direction (along the X axis).

(17) According to the X value of the observer's position, the deflector 30 may changes the refraction angle of the light of the hologram images. For example, when the observer's position has a positive value on the X axis, the deflector 30 may form the first prism pattern to refract the light of hologram images to the + direction. On the other hand, when the observer's position has a negative value on the X axis, the deflector 30 may form the second prism pattern to refract the light of hologram images to the direction. In addition, when the difference between the observer's position and the reference position is not larger than the predetermined threshold value, the controller 80 decides that the observer is stay on the reference position. In that case, the deflector 30 does not form any prism pattern so that the light of the holography image is passing through the deflector 30 as it is.

(18) The deflector driver 60 may include a look-up-table (or LUT) having the first driving voltage group for transmitting the light as is, the second driving voltage group for refracting the light to + direction, and the third driving voltage group for refracting the light to direction. In this case, responding to the controlling signal from the controller 80, the deflector driver 60 may output any selected one of the first to third driving voltage groups. Here, the look-up-table may include a plurality of the second driving voltage groups and a plurality of the third driving voltage groups in order that the prism pattern may have various inclined angles for corresponding to the various positions of the observer

(19) Hereinafter, referring to FIGS. 3 and 4, we will explain about the various prism patterns of the light path deflecting panel, the deflector. FIG. 3 illustrates the prism pattern for refracting the light to the + direction, and FIG. 4 illustrates the prism pattern for refracting the light to the direction.

(20) As shown in figures, in the ECB mode, the prism pattern 1PP and 2PP can be represented by controlling the alignment direction of the liquid crystal molecules. In the ECB mode, the liquid crystal molecules can have any direction angle between the horizontal state (X axis on the FIGS. 3 and 4) to the surface of the substrate and the vertical state (Z axis on the FIGS. 3 and 4) to the surface of the substrate. In the ECB mode, when the liquid crystal molecules are aligned to the vertical direction to the surface of the substrate, the refraction ratio, no, is the minimum value. When the liquid crystal molecules are aligned to the horizontal direction to the surface of the substrate, the refraction ratio, ne, is the maximum value. As the light from the hologram display panel 10 is horizontally polarized, the refraction ratio of this polarized light may be changed according to the alignment direction of the liquid crystal molecules of the deflector 30. When the horizontally polarized light is passing through the vertically aligned liquid crystal molecules, the refraction ratio may be the minimum value, no. When the horizontally polarized light is passing through the horizontally aligned liquid crystal molecules, the refraction ratio may be the maximum value, ne.

(21) By controlling the aligned directions of the liquid crystal molecules included in one pitch 1P of the prism pattern 1PP and 2PP as to be progressively changed from vertical state to the horizontal state along to the +X axis, it is possible to make a prism pattern having the inclined angle of +, as shown in FIG. 3. By controlling the aligned direction of the liquid crystal molecules along to the X axis, it is possible to make a prism pattern having the inclined angle of , as shown in FIG. 4.

(22) At first, in the case the prism pattern has the inclined angle of +, as shown in FIG. 3, the first electrodes 33 are supplied with the second driving voltage including the gradually decreased voltages along to the +X axis. To the second electrode 34, a ground or reference voltage may be supplied. For example, 5 first electrodes 33 are disposed within the one pitch 1P of the first prism pattern 1PP; along to the +X axis, {circle around (a)} electrode, {circle around (b)} electrode, {circle around (c)} electrode, {circle around (d)} electrode and {circle around (e)} electrode are disposed. The V1 voltage is supplied to the {circle around (a)} electrode, the V2 voltage is supplied to the {circle around (b)} electrode, the V3 voltage is supplied to the {circle around (c)} electrode, the V4 voltage is supplied to the {circle around (d)} electrode and the V5 voltage is supplied to the {circle around (e)} electrode. Here, these 5 voltages should be gradually decreased that is, the relations between them would be V1>V2>V3>V4>V5.

(23) Further, in the case the prism pattern has the inclined angle of , as shown in FIG. 4, the first electrodes 33 are supplied with the third driving voltage including the gradually increased voltages along to the +X axis. To the second electrode 34, a ground or reference voltage may be supplied. For example, 5 first electrodes 33 are disposed within the one pitch 1P of the first prism pattern 1PP; along to the +X axis, as mentioned above. Here, these 5 voltages should be gradually increased, that is, the relations between them would be V1<V2<V3<V4<V5.

(24) When the observer is on the reference position, the liquid crystal molecules are in the initial aligned condition. That is, no electric power is supplied to the first electrodes. In the ECB mode, when no electric field is supplied to the liquid crystal cell, all liquid crystal molecules are aligned in the initial alignment direction, horizontal direction. In that case, the refraction ratios of the liquid crystal cells have the same value, ne. Therefore, the horizontally polarized light from the hologram display panel 10 would transmit the deflector 30 without any refraction.

(25) In the deflector 30 as mentioned above, the first electrodes 33 supplied with the driving voltages should be disposed having 2 micrometer (m) gap at most. Forming the first electrodes 33 having the fine pitch like this, the neighboring first electrodes 33 may be shorted each other, or any first electrode 33 may be broken (disconnected).

(26) Considering these problems, in the present disclosure, the first electrodes may be formed as shown in FIG. 5. FIG. 5 is a plan view illustrating the array structure of the first electrodes of the light path deflecting panel (deflector).

(27) Referring to FIG. 5, the first electrodes 33 are disposed in horizontal direction across the substrate. Two neighboring first electrodes are apart 2 micrometer (m) at most from each other. In order to form the prism patterns 1PP and 2PP, a plurality of the first electrodes 33 is included in one group. As shown in FIG. 5, the each of the first electrode group G1, G2, . . . Gn includes 5 first electrodes. For example, the first group G1 includes {circle around (a)} electrode, {circle around (b)} electrode, {circle around (c)} electrode, {circle around (d)} electrode and {circle around (e)} electrode. The voltages of V1, V2, V3, V4 and V5 are supplied to the 5 first electrodes, respectively. Similarly, the second group G2 includes {circle around (a)} electrode, {circle around (b)} electrode, {circle around (c)} electrode, {circle around (d)} electrode and {circle around (e)} electrode. That is, in the present disclosure, all first electrodes are grouped in n groups G1, G2, . . . Gn. Each group has 5 first electrodes.

(28) The deflector (light path deflecting panel) 30 can be divided into two areas; the one is display area AA and the other is non-display area NA. One end of one first electrode 33 is connected to one end of other first electrode 33 by the connection electrode 331 in the non-display area NA. In this embodiment, the connection electrode 331 includes the first connection electrode 331a to the fifth connection electrode 331e.

(29) The first connection electrode 331a is running across the panel along the X axis crossing the first electrodes 33. One end of the first connection electrode 331a is extended to one end of the panel to form a pad portion PAD. The first connection electrode 331a is connected to {circle around (a)} electrode of each group via the first node N1.

(30) The second connection electrode 331b is disposed as being parallel and neighbored with the first connection electrode 331a. One end of the second connection electrode 331b is extended to the one end of the panel to form the pad portion PAD. The second connection electrode 331b is connected to {circle around (b)} electrode of each group via the second node N2.

(31) The third connection electrode 331c is disposed as being parallel and neighbored with the second connection electrode 331b. One end of the third connection electrode 331c is extended to the one end of the panel to form the pad portion PAD. The third connection electrode 331c is connected to {circle around (c)} electrode of each group via the third node N3.

(32) The fourth connection electrode 331d is disposed as being parallel and neighbored with the third connection electrode 331c. One end of the fourth connection electrode 331d is extended to the one end of the panel to form the pad portion PAD. The fourth connection electrode 331d is connected to {circle around (d)} electrode of each group via the fourth node N4.

(33) The fifth connection electrode 331e is disposed as being parallel and neighbored with the fourth connection electrode 331d. One end of the fifth connection electrode 331e is extended to the one end of the panel to form the pad portion PAD. The fifth connection electrode 331e is connected to {circle around (e)} electrode of each group via the fifth node N5.

(34) In addition, all {circle around (a)} electrodes of each group are connected via the first connection line 333a. All {circle around (b)} electrodes of each group are connected via the second connection line 333b. All {circle around (c)} electrodes of each group are connected via the third connection line 333c. All {circle around (d)} electrodes of each group are connected via the fourth connection line 333d. All {circle around (e)} electrodes of each group are connected via the fifth connection line 333e.

(35) At the non-display area NA, one end of the n.sup.th first electrode 33 is connected to the same n.sup.th first electrodes 33 of other group by the connection electrode 331. The connection electrodes 331 form the pad portion PAD at one end side of the substrate. Further, the other end of the n.sup.th first electrode 331 is connected to the same n.sup.th first electrode 33 of other group by the connection line 333.

(36) To the pad portion PAD, a conductive flexible film, such as COF (Chip On Film) on which IC package is mounted, may be attached to connect the connection electrode 331 to the driver IC. The driving voltages may be supplied to the {circle around (a)} electrode, the {circle around (b)} electrode, the {circle around (c)} electrode, the {circle around (d)} electrode and the {circle around (e)} electrode included in each group G1, G2, . . . Gn via the IC package and the connection electrode 331. As the first connection electrode 331a is connected to all {circle around (a)} electrodes of all groups via the first node N1, V1 voltage received from the IC package can be supplied to all {circle around (a)} electrodes.

(37) Further, as all {circle around (a)} electrodes are also connected via the first connection line 333a, even though if any one {circle around (a)} electrode is not connected to the connection electrode 331a, that is if any first node N1 is failed, the voltage V1 can be supplied to the disconnected {circle around (a)} electrode via the first connection line 333a.

(38) As the same n.sup.th first electrodes of all group are connected each other, the number of the IC package can be minimized. If not, each first electrode should have its own channel for IC package, so that the IC package's number may be equal to or larger than the integer number of (the number of the first electrode)/(number of channel per IC package). However, according to the present disclosure, only one IC package having 5 channels would be enough.

(39) In the above embodiment, each group of the first electrodes is driven with the same driving voltages. However, each group may be driven by different driving voltages. In this case, other IC packages may be required for supplying different driving voltages and the groups using the same driving voltages may be connected same IC package.

(40) In addition, the first electrodes 33 disposed in the display area AA may be made of a transparent conductive electrode. The connection electrode 331 and the connection line 333 disposed in the non-display area NA may be made of metal electrode. In that case, the transparent conductive electrode and the metal electrode are formed at different layers, respectively having an insulating layer therebetween. Then, they can be electrically connected each other via contact hole formed at the non-display area. This structure will be explained referring to FIGS. 6 and 7.

(41) FIG. 6 is a cross sectional view along the cutting line VI-VI in the display area AA of FIG. 5. In FIG. 6, the deflector 30 includes a first substrate 31, a second substrate 32 and a liquid crystal cell disposed between the first substrate 31 and the second substrate 32.

(42) The first substrate 31 facing with the hologram display panel 10 may be made of a transparent plastic substrate or a glass substrate. The first substrate 31 is disposed at the light incident side of the deflector 30. On the first substrate 31, a plurality of the first electrodes 33 are formed. The first electrode 33 may be formed by depositing a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) and patterning it through the photolithography method. The first electrodes 33 may be a line pattern running along to one direction of the first substrate 31. The neighboring first electrodes 33 are apart with predetermined distance from each other and disposed in parallel.

(43) In FIG. 6, the first electrodes 33 are running along to the Z axis in parallel each other. For example, the direction of Z axis is perpendicular to the polarization direction of the light from the hologram display panel 10. A first insulating layer 35a and a second insulating layer 35b are deposited on the first electrodes 33. The first and second insulating layers 35a and 35b may include the silicon nitride SiNx or the silicon oxide SiOx.

(44) The second substrate 32 may be made of a transparent plastic substrate or a glass substrate, like the first substrate 31. The second substrate 32 is disposed at the light radiated side of the deflector 30.

(45) On the second substrate 32, a second electrode 34 is formed. Unlike the first electrodes 33, the second electrode 34 is formed as one body by depositing a conductive material on the whole surface of the second substrate 32. The second electrode 34 can be made of the transparent conductive materials including indium-tin-oxide (ITO) or indium-zinc-oxide (IZO), for transmitting the light. On the second electrode 34, a third insulating layer 36 is deposited to protect the second electrode 34. The third insulating layer 36 may include the silicon nitride SiNx or the silicon oxide SiOx.

(46) Between the first substrate 31 and the second substrate 32, a plurality of column spacers CS are disposed for keeping the cell gap, the joining distance between the first substrate 31 and the second substrate 32, evenly. Over the spacer CS, black matrixes BM is disposed for preventing the light from being reflected by the column spacers CS or being recognized by any observer.

(47) FIG. 7 is a cross sectional view along the cutting line VII-VII and VIII-VIII of FIG. 5. FIG. 7 illustrates the structure of the node connecting between the metal connection electrode 331 and the transparent first electrode 33 or between the connection line 333 and the transparent first electrode 33.

(48) The transparent first electrode 33 is formed on the first substrate 31. Over the transparent first substrate 33, the first insulating layer 35a is deposited. Some portions of the transparent first electrode 33 are exposed through the first contact hole CH. The metal connection electrode 331 or the metal connection line 333 is formed over the exposed first electrode 33 so that the first electrode 33 can be connected to the connection electrode 331 or to the connection line 333. Over the first insulating layer 35a, the second insulating layer 35b may be further deposited.

(49) The liquid crystal cell LC disposed between the first substrate 31 and the second substrate 32 may include the ECB (Electrically Controlled Birefringence) mode liquid crystal material.

(50) FIG. 8 is a drawing explaining one method for driving the hologram display according to the present disclosure.

(51) Referring to FIG. 8, at the step S101, the hologram display panel 10 receives the hologram pattern data and displays hologram pattern to represent the hologram images.

(52) At the step S102, the detecting camera 90 takes pictures of the observer and sends the picture images to the controller 80. The controller 80 analyzes the picture images to calculate the coordination of the observer's position. The controller 80 compares the calculated coordination of the observer's position with the coordination of the reference position to decide the relative coordination of the observer's position. If the observer's position is shifted to + from the reference position, the controller 80 sends the second driving voltage corresponding to the observer's position to the light path deflecting panel (or deflector) 30. The deflector 30 forms a prism pattern to refract the light from the hologram display panel 10 to the correct position of the observer.

(53) According to the moved position of the observer, that is, it is shifted to + or , the deflector 30 forms different prism pattern to refract the light properly. For example, when the observer moves to + direction, the deflector 30 may form the prism pattern as shown in FIG. 4 to refract the light to +. When the observer moves to direction, the deflector 30 may form the prism pattern as shown in FIG. 5 to refract the light to . Therefore, the hologram 3D images can be radiated to the proper position of the observer, as shown at the steps S103 to S106.

(54) In other hand, at the step S107, when the movement of the observer's position by detecting and calculating the position of the observer is less than a predetermined threshold value, it is decided as the observer has not moved. The deflector 30 may not form any prism pattern so that the light from the hologram display panel 10 may pass the deflector 30 as is.

(55) As mentioned above, in one embodiment of the present disclosure, the light path deflecting panel (or deflector) 30 may be disposed between the hologram display panel 10 and the observer. The deflector 30 can form various prism patterns corresponding to the left or right shifting amount of the observer's position. As a result, the deflector 30 can control the direction of the light for representing the hologram images. According to the present disclosure, as the hologram images can follow the varied position of the observer, it is possible to enjoy the hologram images, even though the observer moves out of view angle of the hologram image system having the narrow view angle.

(56) Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.