KR102028998B1 - Holographic display device having a Spatial Light Modulator - Google Patents

Abstract

The present invention relates to a holographic display device including a spatial light modulator, wherein a half mirror layer and a reflective polarizer are disposed on a spatial light modulator of a single panel for phase modulation, so that light of two adjacent pixel regions overlaps and is emitted. It is a technical feature to prevent the defect by misalignment.

Description

Holographic display device having a Spatial Light Modulator

The present invention relates to a holographic display device for implementing a hologram using a spatial light modulator.

The stereoscopic image may be divided into images provided to the left and right eyes of a viewer using a light splitter, and a method of reproducing an electronically generated hologram using a spatial light modulator (SLM).

Since the spatial light modulator uses a light interference phenomenon, natural parallax may be provided. However, since the method using the spatial light modulator must modulate both the intensity and phase of the light passing through, the holographic display apparatus for implementing a stereoscopic image using the spatial light modulator has a spatial light modulator and phase for modulation of the intensity. It may include all of the spatial light modulator for modulation of. Accordingly, in the holographic display device including the spatial light modulator, the production cost is increased.

In addition, in the holographic display apparatus, a deviation due to misalignment of the spatial light modulator for modulating the intensity and the spatial light modulator for modulating the phase may be largely generated. In addition, in the holographic display device, an unintended parallax may be generated according to a distance between the spatial light modulator for modulating the intensity and the spatial light modulator for modulating the phase. Accordingly, in the holographic display device including the spatial light modulator, the burden of alignment may be high. Therefore, the holographic display device including the spatial light modulator has a problem that the productivity is greatly reduced.

The problem to be solved by the present invention is to provide a holographic display device comprising a single spatial light modulator.

The problem to be solved by the present invention is not limited to the above-mentioned problem. Tasks not mentioned here will be apparent to those skilled in the art from the following description.

The holographic display device according to the spirit of the present invention for achieving the above object includes a light source unit. The spatial light modulator is located on the light source unit. On the spatial light modulator is a front linear polarizer. The front quarter wave plate is positioned on the front linear polarizer plate. The barrier is located on the front quarter wave plate. On the barrier is a rear quarter wave plate. The reflective polarizer is positioned on the rear quarter wave plate. The front quarter wave plate includes first polarization regions and second polarization regions. The second polarization regions are located between the first polarization regions. The barrier includes transflective regions corresponding to the second polarization regions. The phase of light passing through the second polarization regions is delayed in a direction opposite to the phase of light passing through the first polarization regions.

The light source unit may emit straight light traveling at an angle with respect to an interface between the first polarization regions and the second polarization regions.

Light passing through the first polarization regions may overlap with light passing through the second polarization regions by the reflective polarizer and the transflective regions.

The phase of the light passing through the rear quarter wave plate may be delayed in the same direction as the phase of the light passing through the second polarization regions.

The spatial light modulator may include first pixel regions corresponding to the first polarization regions and second pixel regions corresponding to the second polarization regions. The size of the second pixel areas may be the same as the size of the first pixel areas.

Each pixel area may include a display area and a non-display area. The display area of the second pixel area may have a smaller size than the display area of the first pixel area.

The barrier may comprise a half mirror layer located within the transflective area.

The barrier may further comprise a transparent substrate supporting the half mirror layer.

The half mirror layer may include a region corresponding to the first polarization regions of the front quarter wave plate.

The rear linear polarizer may be positioned on the reflective polarizer. The transmission axis of the rear linear polarizer may be the same as the transmission axis of the reflective polarizer.

The transmission axis of the reflective polarizer may be perpendicular to the transmission axis of the front linear polarizer.

In the holographic display device according to an exemplary embodiment of the present invention, light passing through adjacent pixel regions may be overlapped and output by a half mirror layer and a reflective polarizer positioned on a spatial light modulator. Accordingly, in the holographic display device according to the spirit of the present invention, a single spatial light modulator may be used to implement a stereoscopic image. Therefore, in the holographic display device according to the spirit of the present invention, productivity and the quality of a stereoscopic image may be improved.

1 is a schematic view of a holographic display device according to an embodiment of the present invention.
2A to 2I illustrate a movement path and a polarization state of light passing through first pixel areas of a spatial light modulator and first polarization areas of a front quarter wave plate in a holographic display device according to an exemplary embodiment of the present invention. The drawings.
3A and 3B illustrate a movement path and a polarization state of light passing through second pixel areas of a spatial light modulator and second polarization areas of a front quarter wave plate in a holographic display device according to an exemplary embodiment of the present invention. The drawings.
4A to 4C illustrate pixel areas of a spatial light modulator of a holographic display device according to another exemplary embodiment.
5A and 5B are schematic views illustrating a holographic display apparatus according to another exemplary embodiment of the present invention.

Details of the above objects, technical configurations, and effects according to the present invention will be more clearly understood by the following detailed description with reference to the drawings showing embodiments of the present invention. Here, since the embodiments of the present invention are provided to sufficiently convey the technical spirit of the present invention to those skilled in the art, the present invention may be embodied in other forms so as not to be limited to the embodiments described below.

In addition, parts denoted by the same reference numerals throughout the specification means the same components, in the drawings the length and thickness of the layer or region may be exaggerated for convenience. In addition, when the first component is described as being "on" a second component, the first component is located above and in direct contact with the second component, as well as the first component and the It also includes the case where the third component is located between the second components.

Here, the terms "first" and "second" are used to describe various components, and are used for the purpose of distinguishing one component from other components. However, the first component and the second component may be arbitrarily named for convenience of those skilled in the art without departing from the technical spirit of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, a component expressed in the singular includes a plural component unless the context clearly indicates the singular. Also, in the context of the present invention, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described on the specification, or one or It should be understood that no other features or numbers, steps, actions, components, parts, or combinations thereof are excluded in advance.

In addition, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and, unless expressly defined in the specification of the present invention, in ideal or excessively formal meanings. Not interpreted.

(Example)

1 is a schematic view of a holographic display device according to an embodiment of the present invention.

Referring to FIG. 1, a holographic display device according to an exemplary embodiment of the present invention includes a spatial light modulator 100, a light source unit 200, a half mirror layer 300, a front linear polarizer 400, and a front quarter wavelength. The plate 510, the rear quarter wave plate 520, and the reflective polarizer 600 may be included.

The spatial light modulator 100 may modulate the light passing through the interference pattern according to the information of the stereoscopic image to be implemented. For example, the spatial light modulator 100 may modulate the phase of the light passing through. The spatial light modulator 100 may include a plurality of pixel areas PX1 and PX2. Each of the pixel areas PX1 and PX2 may have the same size.

The light source unit 200 may emit straight light toward the spatial light modulator 100. For example, the light source unit 200 may emit light having a short wavelength such as a laser.

The half mirror 300 may be located on the spatial light modulator 100. Light whose phase is modulated by the spatial light modulator 100 may travel toward the half mirror 300. For example, the spatial light modulator 100 may be located between the light source unit 200 and the half mirror 300.

The half mirror 300 may partially reflect incident light. For example, only about half of light incident to the half mirror 300 may pass through the half mirror 300. The half mirror 300 may include a semi-transimissive material. For example, the half mirror 300 may include a metal thin film such as magnesium (Mg), silver (Ag), and aluminum (Al).

The front linear polarizer 400 may be located between the spatial light modulator 100 and the half mirror 300. Light traveling from the spatial light modulator 100 toward the half mirror 300 may pass through the front linear polarizer 400. The front linear polarizer 400 may have a transmission axis in a first direction. For example, the light traveling from the spatial light modulator 100 toward the half mirror 300 may be linearly polarized in the first direction by the front linear polarizer 400.

The front quarter wave plate 510 may be located between the front linear polarizer 400 and the half mirror 300. Light passing through the front linear polarizer 400 may pass through the front quarter wave plate 510. The front quarter wave plate 510 may delay the phase of incident light. For example, the light passing through the front quarter wave plate 510 may be circularly polarized.

The front quarter wave plate 510 may include first polarization regions PA1 and second polarization regions PA2. The first polarization areas PA1 and the second polarization areas PA2 may correspond to the plurality of pixel areas. For example, the spatial light modulator 100 may include first pixel regions PX1 corresponding to the first polarization regions PA1 and second pixel regions corresponding to the second polarization regions PA2. (PX2) may be included. The second polarization regions PA2 may be located between the first polarization regions PA1. For example, the first polarization regions PA1 and the second polarization regions PA2 may cross each other in a row direction. The first pixel areas PX1 and the second pixel areas PX2 of the spatial light modulator 100 may be alternately positioned in a row direction.

The phase of the light passing through the second polarization areas PA2 may be delayed in a direction opposite to the phase of the light passing through the first polarization areas PA1. For example, the first polarization regions PA1 may delay the phase of incident light by λ / 4. Light linearly polarized in the first direction may be unidirectionally polarized by the first polarization regions PA1. For example, the second polarization regions PA2 may delay a phase of incident light by -λ / 4. The light linearly polarized in the first direction may be left circularly polarized by the second polarization regions PA1.

The rear quarter wave plate 520 may be located on the half mirror 300. For example, the half mirror 300 may be located between the front quarter wave plate 510 and the rear quarter wave plate 520. The rear quarter wave plate 520 may retard the phase of incident light. For example, light passing through the rear quarter wave plate 520 may be circularly polarized.

The phase of the light passing through the rear quarter wave plate 520 may be delayed in the same direction as the phase of the light passing through the second polarization regions PA2 of the front quarter wave plate 510. have. For example, the rear quarter wave plate 520 may delay the phase of incident light by -λ / 4. Light circularly polarized by the first polarization regions PA1 of the front quarter wave plate 510 may be converted into light linearly polarized in the first direction by the rear quarter wave plate 520. Can be.

The reflective polarizer 600 may be located on the rear quarter wave plate 520. For example, the rear quarter wave plate 520 may be located between the half mirror 300 and the reflective polarizer 600. The reflective polarizer 600 may reflect light linearly polarized in a specific direction. For example, the reflective polarizer 600 may reflect light linearly polarized in the first direction. Light linearly polarized in a second direction perpendicular to the first direction may pass through the reflective polarizer 600. The reflective polarizer 600 may include an advanced polarizing film (APF) or a dual bright enhanced film (DBEF).

The rear linear polarizer 700 may be positioned on the reflective polarizer 600. The transmission axis of the rear linear polarizer 700 may be the same as the transmission axis of the reflective polarizer 600. For example, the rear linear polarizer 700 may block light linearly polarized in the first direction. Accordingly, in the holographic display device according to an embodiment of the present invention, the quality of a stereoscopic image implemented may be improved.

2A to 2I illustrate a movement path and a polarization state of light passing through first pixel areas of a spatial light modulator and first polarization areas of a front quarter wave plate in a holographic display device according to an exemplary embodiment of the present invention. The drawings. 3A and 3B illustrate a movement path and a polarization state of light passing through second pixel areas of a spatial light modulator and second polarization areas of a front quarter wave plate in a holographic display device according to an exemplary embodiment of the present invention. The drawings.

2A through 2I, 3A, and 3B, the movement path of the light emitted from the light source unit 200 in the holographic display device according to an exemplary embodiment of the present invention will be described. First, as illustrated in FIG. 2A, straight light emitted to the light source unit 200 may be incident at an angle to the spatial light modulator 100. For example, the linear light emitted to the light source unit 200 may have a predetermined inclination angle θ and an interface between the first pixel areas PX1 and the second pixel areas PX2 of the spatial light modulator 100. ) The light source unit 100 may emit straight light traveling obliquely based on an interface between the first polarization regions PA1 and the second polarization regions PA2 of the front quarter wave plate 510. . For example, the straight light emitted from the light source unit 100 may proceed obliquely in the row direction.

As shown in FIG. 2B, the linear light incident on the spatial light modulator 100 may be linearly polarized in the first direction by the front linear polarizer 400. Here, the first direction may be left and right directions. Light linearly polarized in the first direction by the front linear polarizer 400 may travel in the direction of the front quarter wave plate 510.

As illustrated in FIG. 2C, light linearly polarized in the first direction by the front linear polarizer 400 is unidirectionally polarized by the first polarization regions PA1 of the front quarter wave plate 510. Can be. Light circularly polarized by the first polarization regions PA may travel toward the half mirror 300.

As shown in FIG. 2D, light incident on the half mirror 300 may be partially reflected and transmitted by the half mirror 300. Light reflected by the half mirror 300 may have the same polarization rotation direction as before being reflected by the half mirror 300. The propagation direction of the light reflected by the half mirror 300 may be opposite to the direction before the half mirror 300 is reflected. For example, the light reflected by the half mirror 300 toward the front quarter wave plate 510 may be left circularly polarized light.

The phase of the light transmitted through the half mirror 300 may not be changed. Light passing through the half mirror 300 may travel toward the rear quarter wave plate 520. For example, the light passing through the half mirror 300 and incident on the rear quarter wave plate 520 may be right polarized light.

As illustrated in FIG. 2E, light passing through the half mirror 300 may be linearly polarized by the rear quarter wave plate 520. Light linearly polarized by the rear quarter wave plate 520 may travel in the direction of the reflective polarizer 600. The phase of the light passing through the rear quarter wave plate 520 may be delayed in a direction opposite to the phase of the light passing through the first polarization regions PA1 of the front quarter wave plate 510. have. For example, the light passing through the rear quarter wave plate 520 toward the reflective polarizer 600 may be light linearly polarized in the first direction.

As illustrated in FIG. 2F, light linearly polarized in the first direction incident on the reflective polarizer 600 may be reflected toward the rear quarter wave plate 520 by the reflective polarizer 600. .

As illustrated in FIG. 2G, light reflected by the reflective polarizer 600 may pass through the rear quarter wave plate 520. Light passing through the rear quarter wave plate 520 may travel toward the half mirror 300. Since the rear quarter wave plate 520 retards the phase of light in a direction opposite to the front quarter wave plate 510, the polarization rotation direction of the light passing through the rear quarter wave plate 520. May be opposite to the polarization rotation direction of the light passing through the front quarter wave plate 510. The light reflected by the reflective polarizer 600 may travel in a direction opposite to the light emitted from the light source unit 200. For example, the light reflected by the reflective polarizer 600 and passed through the rear quarter wave plate 520 may be right polarized light. The polarization rotation direction of the light reflected by the reflective polarizer 600 and unidirectionally polarized by the rear quarter wave plate 520 passes through the spatial light modulator 100 and the front quarter wave plate 510. It may be in the direction opposite to the polarization rotation direction of the unidirectional polarized light.

Since the light emitted from the light source unit 200 proceeds at an angle, the light reflected by the reflective polarizer 600 by passing through the first polarization regions PA1 of the front quarter wave plate 510 is It may proceed in the direction of the second polarization regions PA2 of the front quarter wave plate 510.

As shown in FIG. 2H, light reflected by the reflective polarizer 600 and unidirectionally polarized by the rear quarter wave plate 520 may be partially reflected by the half mirror 300. . The light reflected by the half mirror 300 may be reversed in phase. For example, the light re-reflected by the half mirror 300 toward the rear quarter wave plate 520 may be left circularly polarized light.

As illustrated in FIG. 2I, the light re-reflected by the half mirror 300 may pass through the rear quarter wave plate 520 and re-inject into the reflective polarizer 600. Since the light reflected by the half mirror 300 and incident on the rear quarter wave plate 520 is left circularly polarized light, the reflective polarizer 600 passes through the rear quarter wave plate 520. The light reincident to may be light linearly polarized in a second direction perpendicular to the first direction. Light linearly polarized by the rear quarter wave plate 520 in the second direction may pass through the reflective polarizer 600.

As shown in FIG. 3A, light passing through the second pixel areas PX2 of the spatial light modulator 100 is linearly polarized in the first direction by the front linear polarizer 400, and the front surface 1 of FIG. A left circular polarization may be performed by the second polarization regions PA2 of the / 4 wave plate 510.

As shown in FIG. 3B, the light circularly polarized by the second polarization regions PA2 may partially pass through the half mirror 300 to travel toward the rear quarter wave plate 520. . Since the phase of the light transmitted through the half mirror 300 is not changed, the light circularly polarized by the second polarization regions PA2 may be directed toward the rear quarter wave plate 520 without changing the phase. Can be. Accordingly, in the holographic display device according to an exemplary embodiment of the present invention, light passing through the second polarization regions PA2 and the half mirror 300 passes through the first polarization regions PA1 to reflect the light. The light may be overlapped with the light reflected in the polarizing plate 600 and the half mirror 300 in order. Since the overlapping light is left circularly polarized light, it may pass through the rear quarter wave plate 520 and the reflective polarizer 600. That is, the holographic display device according to the embodiment of the present invention adjusts the phase of each light at the overlapping point by using the distance between the half mirror 300 and the reflective polarizer 600, the light provided to the user You can control the amplitude of. Accordingly, the holographic display device according to an exemplary embodiment of the present invention may provide a stereoscopic image to a user using only a spatial light modulator for modulating a phase without a spatial light modulator for modulating intensity.

As a result, the holographic display device according to the exemplary embodiment of the present invention has a front linear polarizer 400, a front quarter wave plate 510, a half mirror 300, and a rear quarter on a single spatial light modulator 100. The wavelength plate 520 and the reflective polarizer 600 are disposed, and the first quarter wave plate 510 has the first polarization regions PA1 and the second polarization regions PA2 whose phase delay directions are opposite to each other. By dividing into, a stereoscopic image can be provided to a user. Accordingly, in the holographic display device according to an exemplary embodiment of the present invention, the holographic display device may be manufactured without burdening the alignment of the spatial light modulator 100. Therefore, in the holographic display device according to the embodiment of the present invention, productivity and quality of a stereoscopic image may be improved.

In the holographic display device according to an exemplary embodiment of the present invention, as shown in FIG. 4A, the first pixel areas PX1 and the second pixel areas PX2 of the spatial light modulator 100 have the same size. It can have For example, the pixel areas PX1 and PX2 may include a display area AA and a non-display area NA, respectively. The length d1 of the display area AA of the first pixel area PX1 may be equal to the length d2 of the display area AA of the second pixel area PX2. The non-display area NA of the first pixel area PX1 may have the same size as the non-display area NA of the second pixel area PX2. However, in the holographic display device according to another exemplary embodiment, the display area AA of the first pixel areas PX1 may have a different size from the display area AA of the second pixel areas PX2. Can have For example, as illustrated in FIG. 4B, in the holographic display device according to another exemplary embodiment, the display area AA of each second pixel area PX2 is displayed on each first pixel area PX1. It may have a length d3 smaller than the area AA. Alternatively, as shown in FIG. 4C, in the holographic display device according to another exemplary embodiment, the display area AA of each first pixel area PX1 is defined as the display area of each second pixel area PX2. It may have a length d4 longer than AA). Accordingly, the holographic display device according to another embodiment of the present invention can compensate for the amplitude and intensity of the light passing through the first polarization regions PA1 by the half mirror 300. Therefore, in the holographic display device according to another exemplary embodiment, the deterioration of characteristics due to the luminance deviation of overlapping light may be prevented.

In the holographic display device according to an exemplary embodiment, the half mirror layer 300 is positioned between the front quarter wave plate 510 and the rear quarter wave plate 520. However, as shown in FIG. 5A, in the holographic display device according to another exemplary embodiment of the present invention, the transmission areas TA and the transflectance are disposed between the front quarter wave plate 510 and the rear quarter wave plate. The barrier 800 including the regions HM may be located. For example, as shown in FIG. 5B, the barrier 800 may have a structure in which half mirror layers 820 spaced apart from each other are disposed on the transparent substrate 810. The half mirror layer 820 may overlap the transflective regions HM. Accordingly, in the holographic display device according to another embodiment of the present invention, the light passing through the first polarization regions PA1 of the front quarter wave plate 510 is not lost in intensity or amplitude. The light may overlap the light passing through the second polarization regions PA2 of the fourth wave plate 510. Therefore, in the holographic display device according to another embodiment of the present invention, the quality of a stereoscopic image can be effectively improved.

100: spatial light modulator 200: light source unit
300: half mirror 400: front linear polarizer
510: front quarter wave plate 520: rear quarter wave plate
600: reflective polarizer

Claims (11)

A spatial light modulator located on the light source unit;
A front linear polarizer positioned on the spatial light modulator;
A front quarter wave plate positioned on the front linear polarizer plate and including first polarization regions and second polarization regions positioned between the first polarization regions;
A barrier positioned on the front quarter wave plate and including transflective regions corresponding to the second polarized regions;
A rear quarter wave plate positioned on the barrier; And
Including a reflective polarizer located on the rear quarter wave plate,
The phase of light passing through the second polarization regions is delayed in a direction opposite to the phase of light passing through the first polarization regions,
The light source unit emits straight light traveling obliquely based on an interface between the first and second polarization regions,
The light passing through the first polarization regions overlaps the light passing through the second polarization regions by the transflective regions of the reflective polarizer and the barrier. delete delete The method of claim 1,
The phase of light passing through the rear quarter wave plate is delayed in the same direction as the phase of light passing through the second polarization regions. The method of claim 1,
The spatial light modulator includes first pixel regions corresponding to the first polarization regions and second pixel regions corresponding to the second polarization regions,
And the size of the second pixel areas is the same as the size of the first pixel areas. The method of claim 5,
Each pixel area includes a display area and a non-display area,
The display area of the second pixel area is smaller than the display area of the first pixel area. The method of claim 1,
And the barrier comprises a half mirror layer positioned within the transflective area. The method of claim 7, wherein
And the barrier further comprises a transparent substrate supporting the half mirror layer. The method of claim 7, wherein
And the half mirror layer includes a region corresponding to the first polarization regions of the front quarter wave plate. The method of claim 1,
Further comprising a rear linear polarizer positioned on the reflective polarizer,
And a transmission axis of the rear linear polarizer is the same as the transmission axis of the reflective polarizer. The method of claim 10,
And a transmission axis of the reflective polarizer is perpendicular to the transmission axis of the front linear polarizer.

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