KR20160042760A - Holographic display apparatus and holographic display method - Google Patents

Abstract

Disclosed are a holographic display device and a holographic display method which prevent binocular crosstalk. The disclosed holographic display device comprises: a space optical modulator configured to form first and second hologram patterns; and a lighting unit configured to provide light. First and second phase modulation values of the first and second hologram patterns are set different from each other to form first and second hologram images to be located in different spaces wherein the first and second hologram images are formed by modulating incident light by first and second hologram patterns, respectively.

Description

[0001] The present invention relates to a holographic display apparatus and a holographic display method,

The disclosed embodiments relate to a holographic display device and a holographic display method, and more particularly to a holographic display device and a holographic display method which are capable of preventing binocular crosstalk while providing hologram images with different viewpoints on the left and right eyes of an observer, To a graphic display device and a holographic display method.

As a method of implementing a three-dimensional image, a spectacle method and a non-spectacle method are widely commercialized and used. There are polarizing glasses and shutter glasses for the glasses, and lenticular and parallax barriers for the glassesless. These methods use the binocular parallax of the two eyes to limit the increase in the number of viewpoints and also cause the viewer to feel fatigue because the depth perception recognized by the brain does not coincide with the focus of the eye do.

Background Art [0002] Recently, a holographic display system has been put to practical use as a three-dimensional image display system in which depth perception recognized by the brain matches the focal point of the eye and can provide full parallax. The holographic display system utilizes the principle that an image of an original object is reproduced by irradiating reference light to a hologram pattern on which interference fringes obtained by interfering with reference light from object light reflected from an original object are diffracted. Currently, the holographic display method that is being put to practical use provides a computer generated hologram (CGH) as an electrical signal to the spatial light modulator, rather than directly exposing the original object to obtain a hologram pattern. The spatial light modulator forms a hologram pattern according to the input CGH signal and diffracts the incident light to generate a three-dimensional image.

However, implementing a complete holographic display scheme requires very high resolution spatial light modulators and very high data throughput. In recent years, a binocular hologram method has been proposed in which a hologram image is provided only to a viewing zone corresponding to both sides of an observer, in order to alleviate data throughput and resolution. For example, only a hologram image having a viewpoint corresponding to the observer's left eye view area and a hologram image having a viewpoint corresponding to the observer's right eye view region are generated and provided to the observer's left eye and right eye, respectively. In this case, since it is not necessary to generate hologram images for the remaining time points, the data throughput can be greatly reduced, and the resolution condition of the spatial light modulator can be satisfied even in the currently commercialized display device.

There is provided a holographic display device and a holographic display method capable of preventing binocular crosstalk while providing hologram images with different viewpoints to the observer's left and right eyes respectively.

A holographic display device according to an exemplary embodiment includes a spatial light modulator forming a holographic pattern for modulating incident light; An illumination unit for providing light to the spatial light modulator; And a control unit for controlling operations of the spatial light modulator and the illumination unit. In order to provide the first hologram image and the second hologram image having different viewpoints, the spatial light modulator controls the first spatial light modulator and the second spatial light modulator, Wherein the control unit is configured to form a second holographic pattern and the different hologram images formed by the first holographic pattern and the second holographic pattern are formed at different spatial positions, And the second phase modulation value of the second holographic pattern can be set differently from each other.

In order to form the first hologram image and the second hologram image alternately in a time division manner, the control unit controls the spatial light modulator to alternately scan the first hologram pattern and the second hologram pattern in a progressive scan manner .

Wherein the spatial light modulator displays a first holographic pattern in a first frame and a second holographic pattern in a second frame subsequent to the first frame, and in the transition period between the first frame and the second frame, A part of the first holographic pattern may be displayed in a part of the modulator and a part of the second holographic pattern may be displayed in the remaining part of the area.

Here, the controller may set the first phase modulation value so that the first hologram image formed by modulating the first hologram pattern through the first hologram pattern during the transition period, and the second hologram image formed by modulating the second hologram pattern with the second hologram pattern, The second phase modulation value can be set to proceed to the second time zone different from the first time zone.

The control unit may control the spatial light modulator to display the first holographic pattern and the second holographic pattern superimposed on one frame.

Here, the controller may set the first phase modulation value so that the first hologram image modulated by the first hologram pattern out of the overlapped first hologram pattern and the second hologram pattern proceeds to the first view region, The second phase modulation value can be set so that the second hologram image formed by modulating the second hologram image is moved to a second view area different from the first view area.

For example, the illumination unit may include one light source unit for providing light.

The first phase modulation value may be set such that a first hologram image formed by modulating the light emitted from the light source unit by the first hologram pattern is incident on the first view area, The second hologram image formed by modulating the light emitted from the first hologram pattern by the second hologram pattern may be set to be incident on the second view region different from the first view region.

Alternatively, the illumination unit may include a first light source unit for providing light for forming the first hologram image and a second light source unit for providing light for forming the second hologram image.

For example, the first phase modulation value may be a value obtained by multiplying the first hologram image formed by modulating the light emitted from the first light source portion by the first hologram pattern into the first view area, and the light emitted from the second light source portion The third hologram image formed by modulating by the first hologram pattern may be set to be incident at a position deviated from the second view area.

The second phase modulation value is a value obtained by modulating the light emitted from the second light source part with the second hologram pattern so that the second hologram image is incident on the second view area, The fourth hologram image formed by modulating the hologram pattern may be set to be incident at a position deviated from the first view area.

The holographic display device may further include a line-of-sight tracing unit for tracing a pupil position of the observer, wherein the control unit adjusts a positional difference between the first hologram image and the fourth hologram image, The first and second phase modulation values may be changed so that the positional difference between the second and third holographic images is greater than the size of the pupil of the observer.

The first light source unit and the second light source unit may be configured to provide light to the spatial light modulator.

Wherein the first hologram pattern is represented by a product of hologram data of a first hologram image and a first phase modulation value and the second hologram pattern is represented by a product of hologram data of a second hologram image and a second phase modulation value have.

A holographic display device according to another embodiment includes a spatial light modulator forming a holographic pattern for modulating incident light; An illumination unit for providing light to the spatial light modulator; And a control unit for controlling operations of the spatial light modulator and the illumination unit. The spatial light modulator includes a first holographic pattern for modulating incident light into a first holographic image, a second holographic pattern for modulating incident light into a second holographic image, Wherein the control unit controls the first phase modulation value of the first holographic pattern and the second phase modulation value of the first holographic pattern so that the difference between the position of the first holographic image and the position of the second holographic image is larger than the size of the pupil of the observer, The second phase modulation value of the second holographic pattern can be set differently.

According to another aspect of the present invention, there is provided a holographic display method including: providing light to a spatial light modulator; And forming a first holographic pattern for modulating light into a first holographic image and a second holographic pattern modulating light into a second holographic image in the spatial light modulator at the same time, The first phase modulation value of the first holographic pattern and the second phase modulation value of the second holographic pattern are set differently so that the difference between the position of the first holographic pattern and the position of the second holographic image is greater than the size of the pupil of the observer .

According to the disclosed holographic display device and holographic display method, binocular crosstalk can be effectively suppressed while providing hologram images with different viewpoints to the observer's left and right eyes respectively. Therefore, in the case of providing the left eye hologram image and the right eye hologram image in a time division manner, there is no need to insert an intermediate frame for preventing cross talk between the frame of the left eye hologram image and the frame of the right eye hologram image, The frame rate of the video signal can be improved. It is also possible to provide the left eye hologram image and the right eye hologram image at the same time.

1 is a block diagram schematically illustrating a configuration of a holographic display device according to an exemplary embodiment of the present invention.
FIGS. 2A and 2B illustrate an operation of a holographic display device that provides a hologram image having a different viewpoint to a left eye view region and a right eye view region of an observer according to a time division method, respectively.
FIG. 3 exemplarily shows a process in which a spatial light modulator scans hologram patterns in a progressive scan manner when providing a hologram image according to a time-division method.
Fig. 4 exemplarily shows the operation of a holographic display device that provides hologram images at different viewpoints in the left and right eye zones of the observer, respectively, without binocular crosstalk during the transition period between the frames.
5 illustrates an operation of a holographic display device that simultaneously provides a hologram image having a different viewpoint to a left eye view region and a right eye view region of an observer.
FIG. 6 exemplarily shows a process in which a spatial light modulator scans hologram patterns when simultaneously providing hologram images with different viewpoints to the left eye view region and the right eye view region of the observer.
7 is a block diagram schematically illustrating a configuration of a holographic display device according to an embodiment.
Figs. 8A and 8B illustrate the operation of the holographic display device shown in Fig. 7, which provides a hologram image at a different viewpoint to the observer's left-eye viewing area and right-eye viewing area, respectively, in a time-division manner.
FIG. 9A illustrates an operation of a holographic display device in which a second light source unit of the holographic display device shown in FIG. 7 provides light to a spatial light modulator to generate a hologram image in a right eye view region of an observer.
FIG. 9B illustrates an operation of the holographic display device in which the first light source unit of the holographic display device shown in FIG. 7 provides light to the spatial light modulator to generate a hologram image in the left eye view region of an observer.
FIG. 10 exemplarily shows a state in which hologram images at different viewpoints are provided in the left eye view region and the right eye view region of the observer without binocular crosstalk.
11 illustrates an exemplary operation of a holographic display device in which a first light source unit and a second light source unit provide light to a spatial light modulator to generate hologram images in a left eye view region and a right eye view region of an observer, respectively.
FIG. 12 is a timing diagram illustrating an exemplary operation of the illumination unit and the spatial light modulator in the method of operating the holographic display device shown in FIG.
13A, 13B, 14A, and 14B show that crosstalk does not occur in the actually formed hologram image.
FIG. 15 exemplarily shows the operation of the holographic display device that simultaneously provides the hologram images having different viewpoints to the left and right eye view regions of the observer.
FIG. 16 is a timing diagram illustrating an exemplary operation of the illumination unit and the spatial light modulator in the operation of the holographic display device shown in FIG. 15. Referring to FIG.

Hereinafter, a holographic display device and a holographic display method will be described in detail with reference to the accompanying drawings. In the following drawings, like reference numerals refer to like elements, and the size of each element in the drawings may be exaggerated for clarity and convenience of explanation. Furthermore, the embodiments described below are merely illustrative, and various modifications are possible from these embodiments. Also, in the layer structures described below, the expressions "top" or "on top"

1 is a block diagram schematically illustrating a configuration of a holographic display device 100 according to an embodiment. The holographic display device 100 according to the present embodiment includes a spatial light modulator 120 forming a hologram pattern for modulating incident light, an illumination unit 110 providing light to the spatial light modulator 120, And a controller 130 for controlling operations of the illumination unit 120 and the illumination unit 110. In addition, the holographic display device 100 may further include a gaze tracking unit 150 for tracking the pupil position of the observer.

The illumination unit 110 may include one light source unit that provides the light focused on the spatial light modulator 120. Although not shown, the illumination unit 110 may further include a collimating lens for focusing the light. Alternatively, the illumination unit 110 may use a light source that emits focused light by itself. Then, the light emitted from the illumination unit 110 can be incident on the spatial light modulator 120 at a right angle. In addition, the illumination unit 110 may include a laser as a light source to provide light having high coherence. However, since the light can be sufficiently diffracted and modulated by the spatial light modulator 120 if the light has some degree of spatial coherence, it is also possible to use a light emitting diode (LED) as the light source. Any other light source can be used if it emits light with spatial coherence in addition to the light emitting diode. Although not shown in detail, one light source portion of the illumination unit 110 may be configured as an array of a plurality of light sources.

The spatial light modulator 120 may form a hologram pattern for modulating the incident light according to the hologram signal provided from the controller 130. The spatial light modulator 120 may use a phase modulator capable of performing only phase modulation, an amplitude modulator capable of performing amplitude modulation only, and a complex modulator capable of performing both phase modulation and amplitude modulation. Although it is shown in FIG. 1 that the spatial light modulator 120 is a transmissive spatial light modulator, it is also possible to use a reflective spatial light modulator. In case of a transmissive type, the spatial light modulator 120 may use a semiconductor modulator based on a compound semiconductor such as GaAs, or a liquid crystal device (LCD). In the case of the reflective type, the spatial light modulator 120 may use, for example, a digital micromirror device (DMD), liquid crystal on silicon (LCoS), or a semiconductor modulator.

The control unit 130 may be configured to generate a hologram signal according to a hologram image to be provided to an observer, provide the hologram signal to the spatial light modulator 120, and control the operation of the illumination unit 110. For example, the control unit 130 may control the lighting unit 110 to turn on and off. The control unit 130 may be implemented using software, or may be implemented in the form of a semiconductor chip in which the functions of such software are embedded.

The gaze tracking unit 150 may obtain an image of an observer through a camera or the like, detect a pupil of the observer in the image, and analyze the position of the pupil. The gaze tracking unit 150 may track the pupil position change of the observer in real time and provide the result to the controller 130. [

The holographic display device 100 having the above-described structure can provide hologram images with different viewpoints to the observer's left eye (EL) and right eye (ER) in a binocular hologram manner, respectively. For example, the holographic display device 100 can recognize the position of the left eye (EL) and the right eye (ER) of an observer by using the eye tracking unit 150, And provide a second holographic image different in viewpoint from the first holographic image in the observer's right eye (ER) field of view. For this purpose, the spatial light modulator 120 may form a first holographic pattern for the first holographic image and a second holographic pattern for the second holographic image, under the control of the controller 130.

For example, FIGS. 2A and 2B illustrate an operation of the holographic display device 100 that provides a hologram image having a different viewpoint to an observer's left-eye (EL) and right-eye (ER) Respectively.

2A, at a first time, the spatial light modulator 120 forms a first holographic pattern PL according to a hologram signal provided from the controller 130. [ The illumination unit 110 provides light to the spatial light modulator 120. Then, the light incident on the spatial light modulator 120 is diffracted and modulated by the first holographic pattern PL, and the object light can be reproduced. The object light thus reproduced can be projected on the left eye (EL) field of view of the observer so that the first hologram image L can be formed. Therefore, at the first time, the observer can see the first holographic image L through the left eye EL.

Here, in order to accurately project the object light to the left eye (EL) field of view of the observer to form the first holographic image (L) in the left eye (EL) field of view of the observer, a phase modulation transfer function transfer function can be used.

Equation 1 above assumes that the spatial light modulator 120 lies in the x-y plane. In Equation (1),? Is an angle between the incident light and the object light, and? Represents the azimuth angle of the object light in the x-y plane.

The first holographic pattern PL can be expressed by the product of the phase modulation value tL of the phase modulation transfer function expressed by Equation 1 and the hologram data HL of the first hologram image L (HL x tL) . The hologram data is created in advance according to the image to be reproduced, and may be, for example, CGH data. That is, the hologram data includes information on the image to be reproduced, and the phase modulation value includes information on the position in the space where the reproduced image is projected. Accordingly, the first holographic pattern PL may include both information on the image to be reproduced and information on the position where the image is to be projected. The phase modulation value may be set such that the first hologram image L formed by modulating the light emitted from the illumination unit 110 with the first hologram pattern PL is incident on the left eye (EL) field of view of the observer. For example, the control unit 130 may calculate the phase modulation value by determining the alpha value and the &thetas; value according to the pupil position of the observer's left eye (EL) provided by the gaze tracking unit 150. [ The control unit 130 may multiply the calculated phase modulation value with the CGH data of the image to generate a hologram signal and provide it to the spatial light modulator 120. The spatial light modulator 120 may form a first holographic pattern PL expressed by a product of a phase modulation value and hologram data according to a hologram signal. Then, the first holographic image L can be formed in the left eye (EL) field of view of the observer according to the phase modulation value of the first holographic pattern PL.

2B, at a second time, the spatial light modulator 120 forms a second holographic pattern (PR = HR x tR) in accordance with the hologram signal provided from the controller 130. The illumination unit 110 provides light to the spatial light modulator 120. Then, the light incident on the spatial light modulator 120 is diffracted and modulated by the second holographic pattern PR, and the object light can be reproduced. The second holographic image R can be formed while the object light thus reproduced is projected to the right eye (ER) field of view of the observer. Therefore, at the second time, the observer can see the second holographic image R through the right eye RL.

The phase modulation transfer function expressed by Equation (1) is used to accurately project the object light to the observer's right eye (ER) field of view to form the second holographic image (R) in the observer's right eye (ER) . For example, the control unit 130 may calculate the phase modulation value by determining the alpha value and the [theta] value according to the pupil position of the observer's right eye (ER) provided by the gaze tracking unit 150. [ The control unit 130 may multiply the calculated phase modulation value with the CGH data of the image to generate a hologram signal and provide it to the spatial light modulator 120. The spatial light modulator 120 may form a second holographic pattern PR expressed by a product of a phase modulation value and hologram data according to a hologram signal. The second holographic image R may be formed in the observer's right eye view region according to the phase modulation value of the second holographic pattern PR.

On the other hand, in the case of the time division method, the spatial light modulator 120 alternately scans the first holographic pattern PL and the second holographic pattern PR alternately in a progressive scan manner. 3, when the first and second holographic images L and R are alternately formed according to the time division scheme, the spatial light modulator 120 sequentially arranges the first and second holographic patterns PL and PR, A scanning method is exemplarily shown. 3, the spatial light modulator 120 first displays a first holographic pattern PL in a first frame, displays a second holographic pattern PR in a second frame subsequent to the first frame, And in the third frame following the second frame, the first holographic pattern PL can be displayed again. Here, the first holographic pattern PL of the first frame and the second holographic pattern PR of the second frame may have different viewpoint information for the same image. In addition, the first holographic pattern PL of the first frame and the first holographic pattern PL of the third frame may have the same image information at the same time and in succession in time.

However, two hologram patterns PL and PR can be simultaneously displayed on the spatial light modulator 120 in the transition period between the frames. For example, in a transition period T1 between the first frame and the second frame, a part of the first holographic pattern PL is displayed in a part of the spatial light modulator 120, and a part of the spatial light modulator 120 And a part of the second holographic pattern PR may be displayed in some remaining areas. Similarly, in the transition period T2 of the second frame and the third frame, a part of the second holographic pattern PR is displayed in a part of the spatial light modulator 120, and a part of the remaining part of the spatial light modulator 120 A part of the first holographic pattern PL may be displayed.

Therefore, if the first holographic pattern PL and the second holographic pattern PR have the same phase modulation value, the first holographic image L in the transition period (T1, T2) Binocular crosstalk may be generated in which the second holographic image R is formed in the left eye (EL) field of view of the observer. In order to prevent such a binocular crosstalk phenomenon, the control unit 130 of the holographic display device 100 according to the present embodiment is constructed such that the time points reproduced by the first holographic pattern PL and the second holographic pattern PR The first phase modulation value tL of the first holographic pattern PL and the second phase modulation value tR of the second holographic pattern PR may be set differently so that different hologram images are formed at different spatial positions have.

For example, FIG. 4 is a block diagram of a holographic display device (L, R) for providing hologram images (L, R) at different points of time in an observer's left eye (EL) The operation of the mobile terminal 100 is illustrated as an example. Referring to FIG. 4, a first holographic pattern PL is formed in a lower region of the spatial light modulator 120, and a second holographic pattern PR is formed in an upper region. The control unit 130 may set the first phase modulation value tL such that the first holographic image L formed by the first holographic pattern PL advances only to the observer's left eye view field, The second phase modulation value tR may be set to be different from the first phase modulation value tL such that the second holographic image R formed by the holographic pattern PR only travels to the observer's right eye view region . Therefore, it is possible to provide the hologram images (L, R) at different viewpoints in the left and right eye viewing regions (ER) and the right eye view region of the observer, respectively, without the binocular crosstalk during the transition period between the frames.

The holographic display device 100 may alternately form the first holographic image L and the second holographic image R in a time-division manner as described above. However, in the characteristics of the hologram, the first holographic pattern PL and the second holographic image R It is also possible to form the first hologram image L and the second hologram image R together by superposing the hologram pattern PR. For example, FIG. 5 shows an operation of the holographic display device 100 that simultaneously provides first and second hologram images L and R with different viewpoints to the observer's left (EL) and right (ER) As shown in FIG. 5, the spatial light modulator 120 superimposes a first holographic pattern (PL = HL x tL) and a second holographic pattern (PR = HR x tR) according to a hologram signal provided from the controller 130 They are displayed together in one frame.

6 is a block diagram of a spatial light modulator 120 according to an embodiment of the present invention when the first and second holographic images L and R having different viewpoints are simultaneously provided to the observer's left (EL) and right (ER) And the second holographic patterns PL and PR are scanned. 6, the spatial light modulator 120 includes first and second overlapping first and second holographic patterns PL1 and PR1 of a first frame, first and second overlapping first and second holographic patterns PL2 and PR2 of a second frame, , And the first and second overlapping holographic patterns PL3 and PR3 of the third frame may be scanned in a progressive scan manner.

Referring again to FIG. 5, even when the first holographic pattern PL and the second holographic pattern PR are superimposed and displayed together in one frame, the first phase modulation value tL of the first holographic pattern PL, And the second phase modulation value (tR) of the second holographic pattern (PR) can be prevented, thereby preventing the binocular crosstalk. For example, when the light emitted from the illumination unit 110 is modulated by the first holographic pattern PL and the second holographic pattern PR, which are displayed together with the spatial light modulator 120, the first hologram image L And a second holographic image R are formed. Here, the first phase modulation value tL of the first holographic pattern PL is selected so that the first hologram image L is directed to the observer's left eye (EL) field of view, The phase modulation value tR may be selected such that the second holographic image R is directed to the observer's right eye view range. Therefore, it is possible to simultaneously form the first hologram image L and the second hologram image R without crosstalk.

Up to this point, it has been described that the illumination unit 110 includes one light source unit. In order to form the first hologram image L and the second hologram image R using only one light source unit, the pixel pitch of the spatial light modulator 120 is sufficiently small so that the spatial light modulator 120 has a high resolution It is advantageous. However, when the illumination unit 110 uses two light sources, the resolution condition of the spatial light modulator 120 can be relaxed.

For example, FIG. 7 is a schematic diagram showing a configuration of a holographic display device 200 according to another embodiment. 7, the holographic display device 200 according to the present embodiment includes a spatial light modulator 120 forming a hologram pattern for modulating light, an illumination unit 110 providing light to the spatial light modulator 120, And a control unit 130 for controlling the operation of the spatial light modulator 120 and the illumination unit 110. In addition, the holographic display device 200 may further include a gaze tracking unit 150 for tracking the pupil position of the observer.

The illumination unit 110 may include a first light source unit 110L for a hologram image to be formed in an observer's left eye EL and a second light source unit 110R for a hologram image to be formed in an observer's right eye ER. The first and second light sources 110L and 110R may be arranged to provide light incident on the spatial light modulator 120 at an angle different from each other. For example, the first light source unit 110L is disposed on the opposite side of the observer's left eye EL with respect to the center of the spatial light modulator 120, and the second light source unit 110R is disposed on the opposite side to the left eye Can be placed on the opposite side of the observer's right eye (ER) relative to the center. The first and second light sources 110L and 110R may be an array of lasers or LEDs capable of providing light having spatial coherence.

In addition, the holographic display device 200 may further include a lens 140 that allows the light to be modulated by the spatial light modulator 120 so that the regenerated light is focused on a predetermined space. The reproduction light is focused on the predetermined space by the lens 140, so that a hologram image can be formed on the space. 7, the lens 140 is disposed between the illumination unit 110 and the spatial light modulator 120, but the present invention is not limited thereto. For example, the lens 140 may be disposed on the front of the spatial light modulator 120, i.e., between the spatial light modulator 120 and the observer. Also, lens 140 may be omitted if illumination portion 110 provides focused light.

For example, FIGS. 8A and 8B illustrate a holographic display device 200 shown in FIG. 7, which provides hologram images with different viewpoints in an observer's left-eye (EL) and right-eye (ER) An operation is exemplarily shown.

Referring to FIG. 8A, at a first time, the spatial light modulator 120 forms a first holographic pattern PL according to a hologram signal provided from the controller 130. The first light source unit 110L provides light to the spatial light modulator 120 under the control of the controller 130. [ Then, the light from the first light source part 110L is diffracted and modulated by the first holographic pattern PL, and the object light can be reproduced. The object light thus reproduced can be projected on the left eye (EL) field of view of the observer so that the first hologram image L can be formed. Therefore, at the first time, the observer can see the first holographic image L through the left eye EL.

As described above, in order to accurately project the object light to the left eye (EL) field of view of the observer to form the first holographic image L in the left eye (EL) field of view of the observer, a phase modulation transfer function . That is, the first holographic pattern PL is expressed by the product (HL x tL) of the phase modulation value tL of the phase modulation transfer function expressed by Equation (1) and the hologram data HL of the first hologram image L . The phase modulation value may be set such that the first hologram image L formed by modulating the light emitted from the first light source part 110L with the first hologram pattern PL is incident on the observer's left eye (EL) field of view .

8B, at a second time, the spatial light modulator 120 forms a second holographic pattern (PR = HR x tR) in accordance with the hologram signal provided from the controller 130. The second light source unit 110R provides light to the spatial light modulator 120 under the control of the control unit 130. [ Then, the object light can be reproduced while the light is diffracted and modulated by the second holographic pattern PR. The second holographic image R can be formed while the object light thus reproduced is projected to the right eye (ER) field of view of the observer. Therefore, at the second time, the observer can see the second holographic image R through the right eye RL.

Here, the phase modulation transfer function expressed by Equation (1) can be used in order to accurately project the object light to the observer's right eye view region to form the second holographic image R in the observer's right eye view region R. [ That is, the second holographic pattern PR is expressed by the product of the phase modulation value t R of the phase modulation transfer function expressed by Equation 1 and the hologram data HR of the second holographic image R (HR x t R) . The phase modulation value is set such that the second holographic image R formed by modulating the light emitted from the second light source part 110R into the second holographic pattern PR is incident on the observer's ER .

3, when the spatial light modulator 120 alternately scans the first holographic pattern PL and the second holographic pattern PR in a progressive scan mode, The two spatial light modulators 120 may simultaneously display two hologram patterns PL and PR. Therefore, if the first holographic pattern PL and the second holographic pattern PR have the same phase modulation value, the first holographic image L in the transition period (T1, T2) Binocular crosstalk may be generated in which the second holographic image R is formed in the left eye (EL) field of view of the observer. For example, in the transition period T1 between the first frame and the second frame, assuming that the second light source section 110R provides light to the spatial light modulator 120 as shown in FIG. 8B, Images different in time point formed by the second holographic pattern PR and the first holographic pattern PL displayed on the modulator 120 may all be formed in the observer's right eye view region. Further, in the transition period T2 of the second frame and the third frame, assuming that the first light source unit 110L provides light to the spatial light modulator 120 as shown in FIG. 8A, the spatial light modulator 120 (EL) field of view by the first holographic pattern PL and the second holographic pattern PR shown in FIG.

In order to prevent such a binocular crosstalk phenomenon, the controller 130 of the holographic display device 200 according to the present embodiment is configured such that the time points formed by the first holographic pattern PL and the second holographic pattern PR are different from each other The first phase modulation value tL of the first holographic pattern PL and the second phase modulation value tR of the second holographic pattern PR may be set to be different from each other so that the hologram image is formed at different spatial positions . For example, FIG. 9A illustrates an operation of the holographic display device 200 in which the second light source 110R provides light to the spatial light modulator 120 to generate a hologram image in an observer's ER (ER) 9B illustrates an operation of the holographic display device 200 in which the first light source unit 110L provides light to the spatial light modulator 120 to generate a hologram image in the left eye (EL) field of view of the observer. As shown in FIG.

Referring to FIG. 9A, the second light source unit 110R provides light to the spatial light modulator 120 in the transition period T1 between the first frame and the second frame. At this time, a part of the second holographic pattern PR may be displayed in a part of the spatial light modulator 120, and a part of the first holographic pattern PL may be displayed in the remaining part of the area. Then, the light emitted from the second light source part 110R enters both the second holographic pattern PR and the first holographic pattern PL. Therefore, the light emitted from the second light source unit 110R is modulated by the second holographic pattern PR and the first holographic pattern PL, so that the second and third hologram images R and L ' . Here, the second holographic image R is a normal image, but the third holographic image L 'is an abnormal image that causes crosstalk in an observer's right eye (ER) viewing area. The controller 130 sets the second phase modulation value tR of the second holographic pattern PR such that the normal second holographic image R is accurately incident on the observer's ER view field. In order to prevent crosstalk, the controller 130 controls the first phase modulation value PL of the first holographic pattern PL so that the third holographic image L 'is incident at a position deviated from the observer's right eye (ER) tL). Then, as shown in FIG. 9A, only the second hologram image R is incident on the observer's right eye (ER) field of view, thereby preventing crosstalk.

Referring to FIG. 9B, the first light source unit 110L provides light to the spatial light modulator 120 in the transition period T2 of the second frame and the third frame. At this time, a part of the first holographic pattern PL may be displayed in a part of the spatial light modulator 120, and a part of the second holographic pattern PR may be displayed in a remaining part of the area. Then, the light emitted from the first light source part 110L is incident on the first hologram pattern PL and the second hologram pattern PR. Accordingly, the first and fourth hologram images L and R ', which are modulated by the first holographic pattern PL and the second holographic pattern PR, respectively, at different timings, emitted from the first light source 110L, . Here, the first hologram image L is a normal image, but the fourth hologram image R 'is an abnormal image that causes crosstalk in an observer's left eye (EL) viewing area. The controller 130 sets the first phase modulation value tL of the first holographic pattern PL so that the normal first hologram image L is accurately incident on the observer's left eye view field. In order to prevent crosstalk, the controller 130 sets the second phase modulation value of the second holographic pattern PR so that the fourth holographic image R 'is incident at a position deviated from the observer's left eye (EL) tR). Then, as shown in FIG. 9B, since only the first hologram image L is incident on the observer's left eye (EL) viewing area, crosstalk can be prevented.

As a result, the first phase modulation value tL is set such that the normal first hologram image L formed by modulating the light emitted from the first light source unit 110L with the first holographic pattern PL is transmitted to the observer's left eye The abnormal third holographic image L 'formed by modulating the light emitted from the second light source part 110R with the first holographic pattern PL is displaced from the ER viewing area of the observer Can be set to be incident. The second phase modulation value tR is set such that a normal second holographic image R formed by modulating the light emitted from the second light source unit 110R with the second holographic pattern PR is incident on the observer's right eye ER, An abnormal fourth hologram image R 'formed by modulating the light emitted from the first light source part 110L with the second holographic pattern PR is incident on the position deviated from the left eye (EL) field of view of the observer, . ≪ / RTI > The first holographic pattern PL is represented by a product (HL x tL) of the hologram data HL of the first hologram image L and the first phase modulation value tL, Can be expressed by the product (HR x tR) of the hologram data HR of the second hologram image R and the second phase modulation value tR.

10, only the normal first hologram image L and the second holographic image R are incident on the pupil of the left eye (EL) of the observer and the pupil of the right eye (ER), respectively, and are recognized by the observer . On the other hand, since the abnormal third hologram image L 'and the fourth holographic image R' are deviated from the pupil of the observer's ER and the pupil of the left eye EL, respectively, they are not recognized by the observer, can do.

As described above, the fourth hologram image R 'formed by modulating the light emitted from the first light source part 110L with the second holographic pattern PR and the light emitted from the second light source part 110R are transmitted through the first Crosstalk caused by the third hologram image L 'formed by modulating by the hologram pattern PL does not occur. Therefore, it is not necessary to alternately turn on the first light source unit 110R and the second light source unit 110R. 11 illustrates an example in which the first light source unit 110L and the second light source unit 110R together provide light to the spatial light modulator 120 to generate a hologram image L, and R, respectively, of the holographic display device 200 according to an embodiment of the present invention. 12 is a timing chart illustrating an exemplary operation of the illumination unit 110 and the spatial light modulator 120 in the operation of the holographic display device 200 shown in FIG.

11 and 12, even if the first light source unit 110R and the second light source unit 110R provide light to the spatial light modulator 120, the normal first hologram image L and the second hologram image L The image R can be correctly recognized by the observer by correctly entering the pupil of the observer's left eye (EL) and the pupil of the right eye (ER), respectively. On the other hand, the abnormal third holographic image (L ') deviates from the pupil of the observer's right eye (ER) and is therefore not recognized by the observer. In addition, the abnormal fourth hologram image (R ') also deviates from the observer's left pupil (EL) and may not be recognized by the observer.

Accordingly, since the first light source unit 110R and the second light source unit 110R need not be operated alternately in synchronization with the frame period of the spatial light modulator 120, the configuration of the holographic display device 200 can be simplified . In addition, according to the present embodiment, when the first hologram image L and the second hologram image R are provided in a time-division manner, the frame of the first hologram image L and the frame of the second hologram image R It is not necessary to insert an intermediate frame for preventing crosstalk, so that the image reproduction speed of the holographic display device 200 can be improved.

On the other hand, when the observer's gaze moves to change the position of the pupil, the control unit 130 calculates the first and second phase modulation values corresponding to the pupil position change of the observer based on the information provided from the gaze tracking unit 150 Can be changed. The control unit 130 may reset the first and second phase modulation values so that crosstalk is not caused even when the first and second phase modulation values change according to the pupil position change of the observer. For example, in response to a change in the pupil position of the observer, the controller 130 calculates the positional difference between the first hologram image L and the fourth hologram image R 'and the positional difference between the second hologram image R and the third hologram image R' The first and second phase modulation values can be changed so that the positional difference between the images L 'is greater than the size of the pupil of the observer.

13A, 13B, 14A, and 14B show that crosstalk does not occur in the actually formed hologram image. 13A, 13B, 14A, and 14B illustrate a method of forming a hologram image in order to confirm that the crosstalk can be removed in the above-described manner, And a hologram image is captured. 13A shows a result of photographing the first hologram image L having a depth of +100 mm with a camera in the left view (EL) field, FIG. 13B shows a result of taking a second hologram image R having a depth of +100 mm, (ER) camera in the city. 14A shows a result of photographing the first hologram image L having a depth of 0 mm with a camera in the left view (EL) field. FIG. 14B shows the result of photographing the second hologram image R having a depth of 0 mm with the right eye ER) is the result of shooting with a camera in the city. As shown in Figs. 13A, 13B, 14A, and 14B, crosstalk was not detected in any images captured by the cameras disposed in the left eye (EL) and right eye (ER) regions respectively.

The holographic display method in which the first holographic image L and the second holographic image R are alternately formed in the time division manner has been described. However, in the characteristics of the hologram, the first holographic pattern PL and the second holographic image PR It is also possible to form the first hologram image L and the second hologram image R together. 15 illustrates an operation of the holographic display device 200 that simultaneously provides first and second hologram images L and R having different viewpoints to an observer's left-eye (EL) and right-eye (ER) Respectively. 16 is a timing chart exemplarily showing the operation of the illumination unit 110 and the spatial light modulator 120 in the operation mode of the holographic display device 200 shown in FIG. 15 and 16, the spatial light modulator 120 superimposes the first holographic pattern PL and the second holographic pattern PR according to the hologram signal provided from the controller 130 and displays the first holographic pattern PL and the second holographic pattern PR together .

6, the spatial light modulator 120 includes first and second overlapping first and second holographic patterns PL1 and PR1 of a first frame, first and second overlapping first and second holograms PL1 and PR1 of a second frame, The patterns PL2 and PR2 and the overlapped first and second holographic patterns PL3 and PR3 of the third frame can be scanned in a progressive scan manner.

Referring again to FIG. 15, even when the first holographic pattern PL and the second holographic pattern PR are overlapped and displayed together in one frame, the first phase modulation value of the first holographic pattern PL and the second phase modulation value of the second holographic pattern PL It is possible to prevent binocular crosstalk by changing the second phase modulation value of the hologram pattern PR. For example, if the light emitted from the first light source part 110L is modulated by the first holographic pattern PL and the second holographic pattern PR, which are displayed together with the spatial light modulator 120, (L) and a fourth hologram image (R ') are respectively formed. Here, the first phase modulation value of the first holographic pattern PL is selected so that the first holographic image L is directed to the observer's left eye (EL) viewing range, and the second phase modulation value of the second holographic pattern PL (tR) may be selected so that the fourth holographic image R 'deviates from the observer's left eye (EL) viewing area. When the light emitted from the second light source unit 110R is modulated by the first holographic pattern PL and the second holographic pattern PR together displayed on the spatial light modulator 120, 'And a second holographic image R are formed. Here, the first phase modulation value tL of the first holographic pattern PL is selected so that the third holographic image L 'deviates from the observer's right eye view range, The two-phase modulation value may be selected such that the second holographic image R is directed to the observer's right eye (ER) field of view. Therefore, it is possible to simultaneously form the first hologram image L and the second hologram image R without crosstalk.

The controller 130 sets the first phase modulation value tL of the first holographic pattern PL and the second phase modulation value tR of the second holographic pattern PR in the above- Torque can be prevented. As described above, since such a control unit 130 can be implemented using software or in the form of a semiconductor chip in which the functions of such software are embedded, additional mechanical or electronic devices are required to prevent crosstalk .

In the above description, the case where the holographic display devices 100 and 200 form two hologram images L and R having different viewpoints are formed in two view areas with different spatial positions, respectively. However, it is also possible to form hologram images having three or more different viewpoints at three or more different viewports, respectively. For example, the spatial light modulator 120 may form three or more hologram patterns sequentially or overlapping each other, and the controller 130 may set different phase modulation values of three or more hologram patterns. Where the controller 130 may set the phase modulation values such that the spacing between the three or more different field of view is greater than the size of the pupil of the observer. For example, the control unit 130 may adjust the phase modulation values of the respective hologram patterns so that the positional difference between the three or more hologram images having different time points reproduced by the three or more hologram patterns is greater than the pupil size of the observer. Can be set.

Up to now, exemplary embodiments of a holographic display device and a holographic display method are described and shown in the accompanying drawings to assist in understanding the technical principles. It should be understood, however, that such embodiments are merely illustrative of the technical principles and are not intended to be limiting. It is to be understood that the scope of the patent rights is not limited to the illustration shown and described. Since various other modifications may occur to those of ordinary skill in the art.

100, 200 ..... Holographic display device
110 ..... illumination units 110L and 110R ..... light source unit
120 ..... spatial light modulator 130 ..... controller
140 ..... lens 150 ..... eye tracking unit

Claims (27)

A spatial light modulator forming a holographic pattern for modulating incident light;
An illumination unit for providing light to the spatial light modulator; And
And a control unit for controlling operations of the spatial light modulator and the illumination unit,
Wherein the spatial light modulator is configured to form a first holographic pattern and a second holographic pattern under the control of the control unit to provide a first holographic image and a second holographic image having different viewpoints,
The controller controls the first phase modulation value of the first holographic pattern and the second phase of the second holographic pattern so that different hologram images formed by the first holographic pattern and the second holographic pattern are formed at different spatial positions, And sets the modulation values to be different from each other. The method according to claim 1,
In order to form the first hologram image and the second hologram image alternately in a time division manner, the control unit controls the spatial light modulator to alternately scan the first hologram pattern and the second hologram pattern in a progressive scan manner A holographic display device. 3. The method of claim 2,
Wherein the spatial light modulator displays a first holographic pattern in a first frame and a second holographic pattern in a second frame subsequent to the first frame, and in the transition period between the first frame and the second frame, A part of the first holographic pattern is displayed in a part of the modulator and a part of the second holographic pattern is displayed in a part of the area. The method of claim 3,
Wherein the controller sets the first phase modulation value so that the first hologram image formed by modulating the first hologram pattern through the first hologram pattern during the transition period sets the first phase modulation value so that the second hologram image formed by modulating the second hologram pattern is the first And sets the second phase modulation value so as to proceed to the second time zone different from the time zone. The method according to claim 1,
Wherein the control unit controls the spatial light modulator to display the first holographic pattern and the second holographic pattern superimposed on one frame. 6. The method of claim 5,
Wherein the controller sets a first phase modulation value so that the first hologram image modulated by the first hologram pattern out of the overlapped first hologram pattern and the second hologram pattern proceeds to the first view region, And sets a second phase modulation value such that the modulated second holographic image proceeds to a second time zone different from the first time zone. The method according to claim 1,
Wherein the illumination unit includes one light source unit for providing light. 8. The method of claim 7,
Wherein the first phase modulation value is set such that a first hologram image formed by modulating the light emitted from the light source part with the first hologram pattern is incident on the first view area, The second hologram image modulated by the second hologram pattern is set to be incident on the second view region different from the first view region. The method according to claim 1,
Wherein the illumination unit includes a first light source unit for providing light for forming the first hologram image and a second light source unit for providing light for forming the second hologram image. 10. The method of claim 9,
Wherein the first phase modulation value is a value obtained by dividing the first hologram image formed by modulating the light emitted from the first light source section by the first hologram pattern into the first view area, And the third holographic image formed by modulating the third holographic image is set to be incident at a position deviated from the second viewing zone. 11. The method of claim 10,
The second phase modulation value is a value obtained by modulating the light emitted from the second light source part by the second hologram pattern into a second view area, and the light emitted from the first light source part is incident on the second hologram pattern And the fourth holographic image formed by modulating the fourth holographic image is set to be incident at a position deviated from the first viewing zone. 12. The method of claim 11,
And a gaze tracking unit for tracking the pupil position of the observer,
Wherein the controller is configured to control a positional difference between the first hologram image and the fourth hologram image and a positional difference between the second hologram image and the third hologram image to be larger than a size of the pupil of the observer, And the first and second phase modulation values are changed. 10. The method of claim 9,
Wherein the first light source unit and the second light source unit together provide light to the spatial light modulator. The method according to claim 1,
Wherein the first hologram pattern is represented by a product of hologram data of a first hologram image and a first phase modulation value and the second hologram pattern is represented by a hologram data of a second hologram image and a second phase modulation value Graphic display device. A spatial light modulator forming a holographic pattern for modulating incident light;
An illumination unit for providing light to the spatial light modulator; And
And a control unit for controlling operations of the spatial light modulator and the illumination unit,
Wherein the spatial light modulator is configured to simultaneously form a first holographic pattern modulating incident light into a first holographic image and a second holographic pattern modulating incident light into a second holographic image,
Wherein the controller controls the first phase modulation value of the first hologram pattern and the second phase modulation value of the second hologram pattern so that the difference between the position of the first hologram image and the position of the second hologram image is larger than the size of the pupil of the observer. And the phase modulation value is set differently. 16. The method of claim 15,
Wherein the illumination unit includes one light source unit for providing light. 17. The method of claim 16,
Wherein the first phase modulation value is set such that a first hologram image formed by modulating the light emitted from the light source part with the first hologram pattern is incident on the first view area, The second hologram image modulated by the second hologram pattern is set to be incident on the second view region different from the first view region. 16. The method of claim 15,
Wherein the illumination unit includes a first light source unit for providing light for forming the first hologram image and a second light source unit for providing light for forming the second hologram image. 19. The method of claim 18,
Wherein the first phase modulation value is a value obtained by dividing the first hologram image formed by modulating the light emitted from the first light source section by the first hologram pattern into the first view area, And the third holographic image formed by modulating the third holographic image is set to be incident at a position deviated from the second viewing zone. 20. The method of claim 19,
The second phase modulation value is a value obtained by modulating the light emitted from the second light source part by the second hologram pattern into a second view area, and the light emitted from the first light source part is incident on the second hologram pattern And the fourth holographic image formed by modulating the fourth holographic image is set to be incident at a position deviated from the first viewing zone. 21. The method of claim 20,
Wherein the controller controls the first and second holographic images so that the positional difference between the first holographic image and the fourth holographic image and the positional difference between the second holographic image and the third holographic image are greater than the size of the pupil of the observer. Is set. Providing light to a spatial light modulator; And
And simultaneously forming a first holographic pattern modulating light into a first holographic image and a second holographic pattern modulating light into a second holographic image in the spatial light modulator,
Wherein a first phase modulation value of the first hologram pattern and a second phase modulation value of the second hologram pattern are different from each other such that a difference between a position of the first hologram image and a position of the second hologram image is larger than a size of a pupil of an observer, And the values are set differently. 23. The method of claim 22,
Wherein the step of providing light to the spatial light modulator is performed using one light source,
Wherein the first phase modulation value is set such that a first hologram image formed by modulating with the first hologram pattern is incident on a first view area, and the second phase modulation value is set to be a second And the hologram image is set to be incident on the second view zone different from the first view zone. 23. The method of claim 22,
The step of providing light to the spatial light modulator is performed using a first light source unit for providing light for forming the first hologram image and a second light source unit for providing light for forming the second hologram image,
The first phase modulation value is obtained by modulating the first hologram image formed by modulating the light emitted from the first light source section with the first hologram pattern into the first view area and outputting the light emitted from the second light source section to the first hologram pattern And the third holographic image formed by modulating the third holographic image is set to be incident at a position deviated from the second viewing zone. 25. The method of claim 24,
The second phase modulation value is obtained by modulating the second hologram image formed by modulating the light emitted from the second light source section with the second hologram pattern into the second view area and outputting the light emitted from the first light source section to the second hologram pattern And the fourth holographic image formed by modulating the fourth holographic image is set to be incident at a position deviated from the first viewing zone. 26. The method of claim 25,
The first and second phase modulation values are set so that the positional difference between the first and fourth hologram images and the difference between the second hologram image and the third hologram image is greater than the size of the pupil of the observer / RTI > 23. The method of claim 22,
Wherein the first hologram pattern is represented by a product of hologram data of a first hologram image and a first phase modulation value and the second hologram pattern is represented by a hologram data of a second hologram image and a second phase modulation value Graphical display method.

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