KR100815354B1 - Colar display apparatus using spatial sperater filter - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color display device, and more particularly, modulates incident light incident from a plurality of light sources through an illumination lens system to generate diffracted light, and then condenses and emits a plurality of light sources to have the same virtual origin. The present invention relates to a color display device using a spatial separation filter for filtering only diffracted light of order and projecting onto a screen. According to the present invention, there is provided an illumination lens system which changes and outputs each of a plurality of light emitted from a plurality of light sources into linear parallel light; A plurality of diffraction type optical modulation systems for modulating the corresponding parallel light among the plurality of parallel light incident from the illumination lens system to form diffracted light having a plurality of diffraction orders; A coupling system for condensing and outputting the plurality of diffracted light beams having the same origin and being separated from each other when a plurality of diffracted light beams each having a plurality of diffraction orders is incident from the plurality of diffractive light modulators; A Fourier filter system for filtering out the diffracted light having a desired diffraction order with respect to each of the plurality of diffracted light collected by the coupling system; And a projection system for focusing and scanning a plurality of diffracted light filtered by the Fourier filter system on a target object.

Color display, light modulator, virtual single light source

Description

Color display apparatus using spatial separation filter {Colar display apparatus using spatial sperater filter}             

1 illustrates a conventional laser scanning method using a single light source and an f-θ lens.

2 is a diagram illustrating a conventional laser scanning method for performing laser scanning by a multi-beam formed by an LED array configured in an image head.

3 is a block diagram of a color display device using a spatial separation filter according to an embodiment of the present invention.

4 is a perspective view, side cross-sectional view, and cross-sectional view including the optical path of the illumination lens of FIG.

5 is a perspective view of the diffraction type optical modulator of FIG.

6 is a view for explaining a reflection angle of the diffraction type optical modulator of FIG.

7 is a schematic diagram of diffracted light generated by the diffractive light modulator of FIG.

8A is a plan view including an optical path according to an embodiment of the coupling system of FIG. 3, and FIG. 8B is a plan view including an optical path according to another embodiment of the coupling system of FIG. 3.

9A and 9B are plan views including the optical path of the Fourier lens of FIG.

10 is a front view of the filter part of FIG. 3.

<Explanation of symbols for the main parts of the drawings>

310: illumination lens system 311: cylinder lens

312: collimator lens 315: diffraction optical modulator

316: diffractive optical modulator 317: reflection mirror

320: coupling system 321: reflection mirror

322 prism 330 Fourier filter system

331: Fourier lens 332: filter unit

340: projection system 350: screen

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color display device, and more particularly, modulates incident light incident from a plurality of light sources through an illumination lens system to generate diffracted light, and then condenses and emits a plurality of light sources to have the same virtual origin. The present invention relates to a color display device using a spatial separation filter for filtering only diffracted light of order and projecting onto a screen.

The light beam scanning apparatus is an image forming apparatus, such as a laser printer, a display apparatus, an LED printer, an electrophotographic copying machine, a word processor, or the like, which scans a light beam and spots the light beam onto a photosensitive medium to form an image image.

The light beam scanning device has been steadily researched and developed to have the characteristics of miniaturization, high speed, and high resolution as the image forming apparatus is developed in the direction of miniaturization, high speed, and high resolution.

The light beam scanning device of the image forming apparatus can be roughly classified into a laser scanning method using an f · θ lens and an image head printer method according to the light beam scanning method and the configuration of the light beam scanning device.

Fig. 1 shows a conventional laser scanning device using a f? Lens. As shown, a conventional laser scanning apparatus includes a laser diode (LD) 10 for emitting a light beam according to a video signal, a collimator lens 11 for converting the light beam output from the LD 10 into parallel light, Cylindrical lens 12 which makes the parallel light which passed through the collimator lens 11 into a horizontal linear light with respect to a scanning direction, and the horizontal linear light which passed through the cylinder lens 12 at the isoline speed are scanned. A polygon mirror 13, a polygon mirror driving motor 14 for rotating the polygon mirror 13 at a constant speed, and a light at an equiangular velocity reflected from the polygon mirror 13 with a constant refractive index with respect to the optical axis. The f · θ lens 15 for deflecting in the direction and correcting the aberration to focus on the irradiated surface, and the surface of the photosensitive drum 17 as an image plane by reflecting a light beam through the f · θ lens 15 in a predetermined direction. Phased into Receives and synchronizes a horizontal synchronous mirror 18 for reflecting the laser beam through the imaging reflective mirror 16, the f? Lens 15 in a horizontal direction, and a laser beam reflected by the horizontal synchronous mirror 18 It is configured to include an optical sensor 19 to fit.

The laser scanning method is difficult to obtain high speed printing due to the low switching speed of the laser diode 10 and the scanning speed of the polygon mirror 13.

That is, in order to increase the scanning speed of the light beam, the polygon mirror 13 must be rotated using a higher speed motor, but in this case, the high speed motor is expensive and the high speed motor generates heat, vibration and noise. Therefore, there is a problem such as lowering the operation reliability, it is not expected to greatly increase the scanning speed.

Another method of improving the speed of the optical scanning device is an image head printing method using a multi-beam type beam forming apparatus.

Such a multi-beam optical scanning device has a plurality of light emitters (laser apex) as a light source means, and a plurality of light beams emitted by the plurality of light emitters by means of an imaging lens via an optical reflector. By imaging, the recording medium surface is simultaneously optically scanned with a plurality of light spots formed on the recording medium surface.

In order to achieve high speed printing using only one light spot, the number of optical scanning of the recording medium surface per unit time should be very large, and as a result, the rotational speed of the light reflector, image clock, etc. Optical scanning cannot be followed. Therefore, if the number of beam spots simultaneously scanning the recording medium surface increases, the rotational speed, image clock, etc. of the light reflector decreases in inverse proportion to the number of beam spots.

As the most effective method of forming a plurality of beam spots, a laser element serving as a light source has a plurality of light emitting points (light emitting portions) that can be driven independently.

Such laser devices having multiple light emission points are generally referred to as "monolithic multi-beam laser elements". When a single crystal multi-beam laser element is used, various optical elements disposed behind the light source can usually be used by a plurality of beams of rays, providing great advantages in cost, operation, adjustment, and the like.

2 is a diagram illustrating a conventional laser scanning method for performing laser scanning by a multi-beam formed by an LED array configured in an image head.

Referring to FIG. 2, a multi-beam beam is formed by forming a large amount of LED array 21 to fill printing paper in the image head 20, so that a laser beam and a f-θ lens are not used unlike a laser scanning method. By printing one line at a time at the same time, print speed can be significantly improved.

Such monolithic multi-beam laser elements include, for example, so-called surface emitting lasers (surface emitting semiconductor lasers).

Surface emitting lasers emit emission beams parallel to the thickness direction of the silicon layer, whereas conventional semiconductor lasers emit light beams in a direction perpendicular to the thickness direction of the silicon layer.

The surface emitting laser has the following characteristics. That is, conventional semiconductor lasers emit elliptical cross-sections and emit divergent rays of varying divergence angles, while surface emitting lasers can emit circular beams with stable divergence angles.

However, surface emitting lasers have a problem of unstable polarization direction of the output light beam. Although the polarization direction can be adjusted to some extent by the manufacturing method, the polarization direction varies with the light emission point, the ambient temperature, and the output.

Usually the reflectance, transmittance of optical elements that make up an optical scanning device such as a polygonal mirror such as a light reflector, a scanning lens as an imaging optical system (f-theta), an echo mirror to change the optical path, and the like, And the angle characteristic changes according to the polarization direction of the input light beam.

For this reason, when a monolithic multi-beam laser element including a surface emitting laser is used as a light source of an optical scanning device, a plurality of beam spots that optically scan the recording medium surface are located at different polarization directions of individual light emission points. According to different strengths. And, this difference in intensity appears as pitch unevenness in the image, which significantly reduces the image quality.

In order to solve this problem, Korean Patent Application No. 2003-77391 has a high speed using a plurality of diffraction beams formed by a piezoelectric / electric distortion diffraction type optical modulator composed of driving cells driven on / off by a driving voltage applied from the outside. Disclosed is a scanning device using a piezoelectric / electric distortion diffraction type optical modulator for performing scanning.

A scanning apparatus using a piezoelectric / electric distortion diffraction type optical modulator according to the disclosed improved technique includes: first lens means for horizontally scanning a single beam output from a predetermined light source in a direction of an optical path; Piezoelectric / consisting of a plurality of drive cells to be turned on / off by the drive power applied from the outside, and generates a plurality of diffraction beams from the single beam by reflection and diffraction phenomenon by the on / off drive between the drive cells Total distortion diffraction type optical modulator; A slit for performing filtering on a diffraction beam having a predetermined diffraction coefficient among a plurality of diffraction beams incident from the piezoelectric / electric distortion diffraction type optical modulator; And second lens means for irradiating a photosensitive surface of the photosensitive member with a diffraction beam having a predetermined diffraction coefficient selectively filtered by the slit.

On the other hand, when the scanning device using the piezoelectric / electrostrictive diffraction type optical modulator according to the conventional improved technique as described above to be used for color display or printing λ1, λ2, λ3. … Since there is a different slit interval for the wavelength of each color, the development of a color display device accordingly has been requested.

In order to satisfy the above-described request, the present invention modulates each of the light emitted from the plurality of light sources to generate diffracted light, and filters only the diffracted light of a desired order from the generated diffracted light so as to be projected onto the screen. It is an object to provide a color display device.

The present invention for achieving the above object is an illumination lens system for changing each of the plurality of light emitted from the plurality of light sources to a linear parallel light and outputs; A plurality of diffraction type optical modulation systems for modulating the corresponding parallel light among the plurality of parallel light incident from the illumination lens system to form diffracted light having a plurality of diffraction orders; A coupling system for condensing and outputting the plurality of diffracted light beams having the same origin and being separated from each other when a plurality of diffracted light beams each having a plurality of diffraction orders is incident from the plurality of diffractive light modulators; A Fourier filter system for filtering out the diffracted light having a desired diffraction order with respect to each of the plurality of diffracted light collected by the coupling system; And a projection system for condensing and scanning a plurality of diffracted light filtered by the Fourier filter system on a target object.

Hereinafter, an operation of the color display apparatus using the space separation filter according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram of a color display device using a space separation filter according to an embodiment of the present invention.

Referring to the drawings, a color display apparatus using a spatial separation filter according to an embodiment of the present invention, a plurality of light sources 300, illumination lens system 310, diffraction type optical modulation system 315, coupling system 320, Fourier filter system 330, projection system 340, screen 350 is composed of.

The plurality of light sources 300 may include, for example, a red light source 301a, a blue light source 301b, and a green light source 301c. The light sources 300 used herein may be light sources manufactured using semiconductors such as light emitting diodes (LEDs) and laser diodes (LDs). Such semiconductor light sources have many properties suitable for use in color display devices compared to other light sources.

An example of a cross-sectional view of such a light source 300 is shown in FIG. 4A. Referring to FIG. 4A, the cross-section of the light source 300 is circular, and the intensity profile of the light is FIG. 4B. As shown in the figure, Gaussian distribution is obtained.

The illumination lens system 310 changes incident light into linear parallel light having an elliptical cross section, and includes a plurality of cylinder lenses 311a to 311c and a plurality of collimator lenses 312a to 312c.

That is, the illumination lens system 310 converts each beam output from each of the light sources 301a to 301c of the plurality of light sources 300 into linear light in a horizontal direction with respect to the optical path direction to be described later. It focuses on 316c, and consists of several cylinder lenses 311a-311c and collimator lenses 312a-312c.

Here, the cylinder lenses 311a to 311c are horizontally incident on the corresponding diffraction type optical modulators 316a to 316c which horizontally position each parallel light incident from the light sources 301a to 301c in the optical path direction. In order to achieve this, as shown in FIG. 4C, the balanced light is converted into linear light in the horizontal direction, and the incident light is incident on the diffractive light modulators 316a to 316c through the corresponding collimator lenses 312a to 312c.

Here, the plurality of collimator lenses 312a to 312c respectively converts spherical light incident from the plurality of light sources 300 through the cylinder lenses 311a to 311c into parallel light, and then corresponds to the corresponding diffractive light modulator 316a. Incident to 316c).

The collimator lens (here described with reference to 312a, but the rest of the same) has a concave lens 312aa and a convex lens 312ab as an example, as shown in FIG.

The concave lens 312aa extends up and down the linear light incident from the cylinder lens 311a and enters the convex lens 312b as shown in FIG. 4D. The convex lens 312ab emits incident light incident from the concave lens 312aa by changing parallel light as shown in Fig. 4E. In Figure 4 (a) is a perspective view of an optical system consisting of a light source, a cylinder lens, a collimator lens, (b) is a plan view in Figure 4, (c) is a side cross-sectional view, Figure 4 (d) is a cut surface. It is also.

Next, the diffraction light modulator 315 is composed of a plurality of diffraction light modulators 316a to 316c and a plurality of reflection mirrors 317a to 317c. Here, the reflection mirrors 317a to 317c reflect the parallel light incident from the illumination lens system 310 and make the reflection mirrors 317a to 316c perpendicular to the corresponding diffraction type optical modulators 316a to 316c. As such, when the incident light incident on the diffractive light modulators 316a to 316c is close to the vertical, the light efficiency is increased by that much.

The diffractive light modulators 316a to 316c preferably reflect or diffract incident incident light as an open hole diffraction light modulator to form diffracted light. In this case, the reflection mirrors 317a to 317c reflect the diffracted light formed by the diffractive light modulators 316a to 316c so that the diffracted light proceeds in the same way as the optical path emitted from the illumination lens system 310.

An example of the open hole diffraction type optical modulators 316a to 316c used herein is shown in FIG. 5. Referring to the drawings, the open hole based diffraction light modulator includes a silicon substrate 501a and an insulating layer ( 502a), the lower micromirror 503a, and the some diffraction members 510a-510n). Here, although the insulating layer and the lower micromirror are configured as separate layers, if the insulating layer has a property of reflecting light, the insulating layer itself can function as the lower micromirror.

The silicon substrate 501a has depressions to provide a space for the diffraction members 510a to 510n, an insulating layer 502a is stacked, and a lower micromirror 503a is deposited thereon, and the depressions are provided. The lower surfaces of the diffraction members 510a to 510n are attached to both sides out of the negative portions. As the material constituting the silicon substrate 501aa, a single material such as Si, Al ₂ O ₂ , ZrO ₂ , quartz (Quartz), SiO _2, and the like is used. It can also be formed using the material of.

The lower micromirror 503a is deposited on the silicon substrate 501a, and reflects and diffracts incident light. As a material used for the lower micromirror 503a, metal (Al, Pt, Cr, Ag, etc.) may be used.

The diffraction member (typically, only the reference numeral 510a is described, but the rest is the same) has a ribbon shape, and the bottom surfaces of both ends thereof are respectively positioned so that the center portion is spaced apart from the depression of the silicon substrate 501a. The lower support part 511a attached to the both side area | regions which deviated from the recessed part is provided.

Piezoelectric layers 520a and 520a 'are provided on both side surfaces of the lower support 511a, and the driving force of the diffraction member 510a is provided by contraction and expansion of the provided piezoelectric layers 520a and 520a'.

The material constituting the lower support 511a includes Si oxide (for example, SiO2), Si nitride series (for example, Si ₃ N _4, etc.), ceramic substrate (Si, ZrO ₂ , Al ₂ O _3, etc.), Si carbide And so on. The lower support 511a may be omitted as necessary.

The left and right piezoelectric layers 520a and 520a 'are stacked on the lower electrode layers 521a and 521a' for providing the piezoelectric voltage and the lower electrode layers 521a and 521a 'and contract and expand when voltage is applied to both surfaces. And the upper electrode layers 523a, which are stacked on the piezoelectric material layers 522a and 522a 'that generate the vertical driving force, and provide the piezoelectric voltage to the piezoelectric material layers 522a and 522a'. 523a '). When voltage is applied to the upper electrode layers 523a and 523a 'and the lower electrode layers 521a and 521a', the piezoelectric material layers 522a and 522a 'contract and expand to generate vertical movement of the lower support 511a.

Pt, Ta / Pt, Ni, Au, Al, RuO _2, etc. may be used as the electrode material of the electrodes 521a, 521a ', 523a, and 523a', and may be sputtered or deposited in a range of 0.01-3 μm. evaporation).

On the other hand, the upper micro mirror is deposited on the central portion of the lower support 511a and has a plurality of open holes. Here, the shape of the open hole is preferably a rectangular shape, but any shape of a closed curve, such as a circle or an ellipse, is possible. If the lower supporter is formed of a light reflective material, it is not necessary to deposit the upper micromirror separately, and the lower supporter may function as the upper micromirror.

The open hole causes incident light to enter the lower micromirror 503a corresponding to a portion where the incident light penetrating the diffraction member 510a corresponds to the open hole. Thus, the lower micromirror 503a and the upper micromirror It is possible to form pixels.

That is, for example, the (a) portion of the upper micro mirror and the (b) portion of the lower micro mirror 503a having the open holes may form one pixel.

In this case, incident light incident through the open hole of the upper micromirror may be incident on a corresponding part of the lower micromirror 503a, and the interval between the upper micromirror and the lower micromirror 503a is an odd number of λ / 4. When doubled, the maximum diffracted light is generated. In addition, the open-hole diffraction light modulator usable in the present invention is disclosed in Korean Application No. P2004-030159.

On the other hand, each of the open-hole diffraction type optical modulators 316a to 316c diffracts each linear light incident from the illumination lens system 310 to form diffracted light as described above, and then combines the diffracted light into the coupling system 320. Incident.

In this case, the reflection angle of the formed diffracted light is shown in FIG. 6. Referring to the drawings, it can be seen that the incident angle and the reflection angle are the same. That is, when the incident angle enters θ ° to the diffraction optical modulators 316a to 316c, the reflection angle becomes θ °.

Next, the diffracted light formed by the diffractive light modulators 316a to 316c is shown in FIG. 7, where zero-order and ± first-order diffraction light are formed in the periodic direction of the grating.

On the other hand, the coupling system 320 includes a plurality of reflection mirrors 321a and 321b and a plurality of prisms 322a and 322b. The plurality of reflecting mirrors 321a and 321b reflect the diffracted light incident from the diffractive light modulator 315 and enter the prism 322a and 322b. In other words, the reflective mirror 321a injects diffracted light into the prism 322a, and the reflective mirror 321b injects diffracted light into the prism 322b.

At this time, the inclination angles of the reflection mirrors 321a and 321b are important. If the inclination angle is properly adjusted, the diffracted light reflected from the prisms 322a and 322b may have a virtual single origin, and this process may be performed. It is well illustrated in 8a and 8b.

FIG. 8A is a cross-sectional view including an optical path according to an embodiment of the coupling system used in the present invention. When the reflective mirrors 321a and 321b are inclined by α ° with respect to a 45 ° angle, the reflected light is 45 ° + 2α °. As a result, the reflected light reflected by the prisms 322a and 322b is also inclined by 2 [deg.]. Therefore, if the value of α is properly adjusted as shown in Fig. 8A, it can be made to appear to come from one point when connecting the virtual path of the reflected light. By adjusting the value of α so that it appears to come from one point when connecting the virtual path of the reflected light, it is possible to focus a plurality of lights to one point using an appropriate lens and to focus the light on the screen 350 to perform scanning. can do.

8A shows a cross-sectional view of the diffracted light passing through the prisms 322a and 322b. In the diffracted light of the first wavelength, the zeroth order diffracted light and the ± first order diffracted light overlap each other. Therefore, the Fourier filter system 330 needs to separate 0th-order diffraction light and ± 1st-order diffraction light. To filter.

8B is a cross-sectional view including an optical path according to another embodiment of a coupling system used in the present invention, and includes a plurality of reflective mirrors 321a to 321c and a beam splitter 322.

As shown in FIG. 8B, when the reflection mirrors 321a to 321c are inclined by α ° with respect to 45 °, the emission angle is 45 ° -2α °. Therefore, when the reflection mirrors 321a to 321c are inclined by α °, the reflection angle changes by 2α when the incident light has no change in angle.

Next, the diffracted light reflected by the reflecting mirrors 321a to 321c is incident on the beam splitter 322, where the incident angle has an increased incident angle of 2α ° compared to the incident light incident at 45 °. As a result, the diffracted light reflected by the beam splitter 322 has a reflection angle of 2α ° with respect to the X-prism plane. Therefore, if the value of α is properly adjusted as shown in Fig. 8B, it can be made to appear from one point when connecting the virtual path of the reflected light. By adjusting the value of α so that it appears to come from one point when connecting the virtual path of the reflected light, it is possible to focus a plurality of lights to one point using an appropriate lens and to focus the light on the screen 350 to perform scanning. can do.

In addition, in FIG. 8B, a cross-sectional view of the diffracted light passing through the beam splitter 322 is shown. In the diffracted light of the first wavelength, the zeroth order diffracted light and the ± first order diffracted light overlap each other. Therefore, the Fourier filter 330 needs to separate the zeroth order diffraction light and the ± first order diffraction light, and use the mechanical filter to separate the diffraction light of the desired order after the zeroth order diffraction light and the ± first order diffraction light are separated. To filter.

Next, the Fourier filter system 330 is preferably composed of a Fourier lens 331 and a filter unit 332. The Fourier lens 331 separates the incident diffracted light by orders, and the filter unit 332 is It has a plurality of spatially separated slits and transmits only diffracted light of the desired order.

Herein, the Fourier lens 331 collects the light emitted from the coupling system 320 as shown in FIGS. 9A and 9B, where FIG. 9A is a plan view and FIG. 9B is a side cross-sectional view.

Referring to FIG. 9A, when three beams having different wavelengths are incident on the Fourier lens 331, the Fourier lens 331 focuses an angular beam.

In addition, FIG. 9B illustrates a side cross-sectional view of any one of the three beams. The zeroth order diffracted light is focused at a point when passing through the Fourier lens 331, where the + 1st order diffracted light is zero. The upper-order diffraction light and the -first-order diffraction light are focused downward from the position where the diffraction light of the difference is focused and the lower direction from the position where the zeroth order diffraction light is focused. If the filter unit 332 is positioned near the condensing point, only the diffracted light of a desired order can pass. At this time, a front view of the filter unit 332 used is shown in FIG. 10. Since the distances of the 0th order diffraction light and the ± 1st order diffraction light are different for each wavelength, it may be separated using the mechanical filter part 332.

Projection system 340 projects the incident diffracted light onto screen 350. That is, the projection system 340 focuses a diffraction beam having a predetermined diffraction coefficient incident through the filter unit 332 on the screen 350 to form a spot, more specifically, a projection lens. .

Using a mechanical filter unit having a plurality of spatially separated slits according to the present invention has the effect of implementing a color image by configuring a simple optical system.

In addition, according to the present invention, the parallel light is vertically incident on the diffractive optical modulator by using the reflection mirror, thereby increasing the diffraction efficiency.

Herein, the present invention described above has been described with reference to preferred embodiments, but those skilled in the art will variously modify the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. And can be changed.

Claims (5)

An illumination lens system which changes each of the plurality of light emitted from the plurality of light sources into linear parallel light and emits the light; A plurality of diffraction type optical modulation systems for modulating the corresponding parallel light among the plurality of parallel light incident from the illumination lens system to form diffracted light having a plurality of diffraction orders; A coupling system that emits a plurality of diffracted light beams having a virtual same origin and adjacent to each other when a plurality of diffracted light beams having a plurality of diffraction orders are incident from the plurality of diffractive light modulation systems; A Fourier filter system for filtering out diffracted light having a desired diffraction order with respect to each of the plurality of diffracted light emitted by the coupling system; And And a projection system configured to collect and scan a plurality of diffracted light filtered by the Fourier filter system onto a target object. The method of claim 1, The diffraction type optical modulation system, A diffraction type optical modulator for modulating a corresponding parallel light among a plurality of parallel lights incident from the illumination lens system to form diffracted light having a plurality of diffraction orders; And And a first reflection mirror configured to reflect incident light incident from the illumination lens system to be incident perpendicularly to the diffractive optical modulator. The method of claim 1, The binding system, A plurality of prisms which transmit and reflect the diffracted light when the diffracted light having a plurality of diffraction orders is incident; And A space comprising a plurality of second reflecting mirrors for injecting diffracted light emitted from the diffractive light modulator into the corresponding prism such that the plurality of diffracted light emitted from the plurality of prisms have virtual identical origins and are adjacent to each other; Color display device using separation filter. The method of claim 1, The binding system, A beam splitter which transmits or reflects each diffracted light when a plurality of diffracted lights having a plurality of diffraction orders are incident; And A plurality of second reflection mirrors for injecting diffracted light incident from the diffractive light modulator into the beam splitter at an angle of incidence such that the plurality of diffracted light emitted from the beam splitter have virtual identical origins and are adjacent to each other; Color display device using a space separation filter comprising a. The method of claim 1, The Fourier filter, A Fourier lens that separates the diffracted light for each of the plurality of diffracted light collected by the coupling system so that the diffracted light is distinguished for each order; And And a filter unit for filtering the diffracted light having a desired order through the spatially separated filter in the diffracted light for each order for each of the plurality of diffracted light separated by the Fourier lens.

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