KR20070010866A - Display apparatus which scans both forward path and backward path - Google Patents

Abstract

A forward/reverse scanning-type display device is provided to increase brightness while using the same light source by increasing light efficiency per hour and to utilize a low-power light source at the same brightness. A forward/reverse scanning-type display device using diffractive light modulators(110R,110G,110B) includes plural diffractive light modulators generating the diffracted light having plural diffraction orders by modulating the incident light according to an external control signal; lighting optical units(108R,108G,108B) irradiating the correspondent light selected from plural lights emitted from plural light sources, to respective diffractive light modulators; a schlieren optical unit(114) selecting the diffracted light of a desirable diffraction order from the diffracted light having plural diffraction orders generated from the plural diffractive light modulators and passing the selected diffracted light; and a scanning optical unit(116) scanning the diffracted light having passed through the schlieren optical unit in forward and reverse directions along a line.

Description

Display apparatus which scans forward and backward mode {Display apparatus which scans both forward path and backward path}

1 is a perspective view of a grating light valve (GLV) of Bloom (Bloom) according to the prior art.

2A and 2B are configuration diagrams of a lattice light valve of SLM (Silicon Light Machine).

3A is a cross-sectional view of a recessed diffraction type optical modulator using piezoelectric materials developed by Samsung Electro-Mechanics, and FIG. 3B is a cross-sectional view of an open hole-based diffraction type optical modulator developed by Samsung Electro-Mechanics.

4 is a configuration diagram of a conventional three-panel optical device using a GLV device as a light modulation device to which a MEMS device is applied, or a piezoelectric diffraction type optical modulator of Samsung Electro-Mechanics.

5A is a structural diagram in which image data input in a typical HDTV or the like is horizontally aligned, and FIG. 5B is a structural diagram in which 1080 diffracted light spots generated by a diffractive optical modulator are arranged in a longitudinal direction. 5C is a scanner trajectory diagram of time versus distance.

6 is a block diagram of a display device of the forward and reverse scanning method according to an embodiment of the present invention.

FIG. 7 is a detailed configuration diagram of the projection and scanning optics of FIG. 6. FIG.

8 is a trajectory diagram of a scanner of time zone distances according to an embodiment of the present invention.

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

102 display optical system 104 display electronic system

106R, 106G, 106B: Laser light source 108R, 108G, 108B: Illumination optics

110R, 110G, 110B: Diffraction type optical modulator 112: Condenser

114: Schlieren optics 116: projection and scanning optics

118: screen

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device using a diffractive optical modulator. In particular, the present invention relates to a forward and reverse scanning in which a diffracted light modulated by the diffractive optical modulator is displayed on the screen not only when the screen is scanned in the forward direction but also in the reverse direction. It relates to a display device of the type.

In accordance with the progress of microtechnology, attention has been paid to small devices incorporating so-called Micro Electro Mechanical Systems (MEMS) devices and MEMS devices.

A MEMS device is a device formed as a microstructure on a substrate such as a silicon substrate or a glass substrate, and electrically and mechanically coupled to a driver for outputting a mechanical driving force, a semiconductor integrated circuit for controlling the driver, and the like. A basic feature of the MEMS device is that a drive body constructed as a mechanical structure is assembled to a part of the device, and the drive of the drive body is performed electrically by applying the coulomb force between the electrodes.

Recently, optical modulators using such MEMS devices have been developed. The optical MEMS element 1 shown in FIG. 1 includes a substrate 2, a substrate side electrode 3 formed on the substrate 2, and a driving side electrode arranged in parallel to the substrate side electrode 3 ( A beam beam 6 having 4) and a support 7 supporting one end of the beam 6 are formed. The beam 6 and the board | substrate side electrode 3 are electrically insulated by the space | gap 8 between them.

In the optical MEMS element 1, the beam 6 is displaced by electrostatic attraction or electrostatic repulsion between the substrate-side electrode 3 and the substrate-side electrode 3 depending on the potential applied to the substrate-side electrode 3 and the driving-side electrode 4. For example, as shown by the solid line and the broken line of FIG. 1, it displaces in parallel and inclined state with respect to the board | substrate side electrode 3, for example.

2A and 2B show the configuration of a GLV (Grating Light Valve) device developed by SLM (Silicon Light Machine) as a light intensity conversion element for a laser display, that is, an optical modulator.

As shown in Fig. 2A, the GLV device 21 has a common substrate side electrode 23 formed on an insulating substrate 22 such as a glass substrate, and crosses the substrate side electrode 23 in a bridge shape. In the plural, in this example, six beams 24 [24 ₁ , 24 ₂ , 24 ₃ , 24 ₄ , 24 ₅ , 24 ₆ ] are arranged in parallel.

The beam 24 which consists of the bridge member 25 and the reflecting film and drive side electrode 26 provided thereon is a site commonly called a ribbon.

When a small voltage is applied between the substrate side electrode 23 and the reflective film and driving side electrode 26, the beam 24 approaches the substrate side electrode 23 due to the above-mentioned electrostatic phenomenon, and the voltage If the application stops, it returns to its original state.

The GLV device 21 is a light reflection film and a driving side electrode by the proximity of the plurality of beams 24 with respect to the substrate-side electrode 23, and the operation between the beams 24 (that is, the proximity of one filtered beam and the operation between the beams). The height of 26 is alternately changed, and the intensity of the light reflected by the drive side electrode 26 is modulated by diffraction of the light (one light spot is irradiated to all six beams 24).

3A is a cross-sectional view of a recessed diffraction type optical modulator using a piezoelectric material developed by Samsung Electro-Mechanics, and FIG. 3B is a cross-sectional view of a diffraction type optical modulator using an open hole-based piezoelectric material developed by Samsung Electro-Mechanics.

Referring to the drawings, the recessed thin film piezoelectric optical modulator developed by Samsung Electro-Mechanics includes a silicon substrate 30 and a plurality of elements 32a to 32n.

Here, the plurality of elements 32a to 32n have a constant width and are aligned regularly to form a recessed thin film piezoelectric optical modulator. In addition, the plurality of elements 32a to 32n have different widths and are alternately arranged to form a recessed thin film piezoelectric optical modulator. In addition, the elements 32a to 32n may be spaced apart from each other at a predetermined interval (almost the same distance as the width of the elements 32a to 32n), and in this case, the micromirrors formed on the entire upper surface of the silicon substrate 30. The layer reflects the incident light and diffracts it.

The silicon substrate 30 has depressions in order to provide air space to the elements 32a to 32n, and an insulating layer 31 is deposited on the upper surface, and ends of the elements 32a to 32n on both sides of the depressions. Is attached.

Each element (herein, only the reference numeral 32a is described in detail, but the remaining 32b to 32n is the same) has a rod shape, and the lower surfaces of both ends are positioned so that the center portion is spaced apart from the recessed portion of the silicon substrate 30. A portion located at both sides of the silicon substrate 30 beyond the depression, and the portion located in the depression of the silicon substrate 30 includes a lower support 33a that is movable up and down.

In addition, the element 32a is stacked on the left end of the lower support 33a, and is laminated on the lower electrode layer 34a and the lower electrode layer 34a for providing a piezoelectric voltage, and contracts and A piezoelectric material layer 35a that expands to generate a vertical driving force, and an upper electrode layer 36a that is stacked on the piezoelectric material layer 35a and provides a piezoelectric voltage to the piezoelectric material layer 35a are included.

In addition, the element 32a is stacked on the right end of the lower support 33a, and is laminated on the lower electrode layer 34a 'and the lower electrode layer 34a' for providing a piezoelectric voltage. A piezoelectric material layer 35a 'that contracts and expands to generate a vertical driving force, and an upper electrode layer 36a' that is stacked on the piezoelectric material layer 35a 'and provides a piezoelectric voltage to the piezoelectric material layer 35a'. Doing.

In addition, Korean Patent Application No. P2004-74875 describes the protruding type in addition to the depression type described above.

3b is a perspective view of an open hole-based diffractive optical modulator developed by Samsung Electro-Mechanics. Referring to FIG. 4B, the open hole-based diffractive light modulator is composed of a silicon substrate 41, an insulating layer 42, a lower micro mirror 43, and a plurality of elements 50a to 50n.

Here, the lower micro mirror 43 is deposited on the silicon substrate 41 and reflects and diffracts incident light. As a material used for the lower micromirror 43, metal (Al, Pt, Cr, Ag, etc.) may be used.

The elements (typically, only the reference numeral 50a is described but the rest are the same) have a ribbon shape, and the bottom surfaces of both ends are recessed in the silicon substrate 41 so that the center portion is spaced apart from the recessed portion of the silicon substrate 41. The lower support part 51a attached to the both side areas | regions which are out of a part is provided.

Piezoelectric layers 60a and 60a 'are provided on both sides of the lower support 51a, and the driving force of the element 50a is provided by contraction and expansion of the provided piezoelectric layers 60a and 60a'.

The left and right piezoelectric layers 60a and 60a 'are stacked on the lower electrode layers 61a and 61a' for providing the piezoelectric voltage and the lower electrode layers 61a and 61a ', and contract and expand when voltage is applied to both surfaces. And the upper electrode layers 63a, which are stacked on the piezoelectric material layers 62a and 62a 'that generate vertical driving force, and which provide piezoelectric voltages to the piezoelectric material layers 62a and 62a'. 63a '). When voltage is applied to the upper electrode layers 63a and 63a 'and the lower electrode layers 61a and 61a', the piezoelectric material layers 62a and 62a 'contract and expand to generate vertical motion of the lower support 51a.

On the other hand, the upper micro mirror (70a) is deposited in the central portion of the lower support (51a) and has a plurality of open holes (71a1 ~ 71a4). Here, the shape of the open holes 71a1 to 71a4 is preferably rectangular, but any closed curve such as circular or elliptical may be used. 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 holes 71a1 to 71a4 allow incident light incident on the element 50a to penetrate the incident light to the lower micromirror 43 corresponding to the portion where the open holes 71a1 to 71a4 are formed. The mirror 43 and the upper micromirror 70a can form pixels.

That is, for example, part (A) of the upper micromirror 70a having the open holes 71a1 to 71a4 and part (B) of the lower micromirror 43 may form one pixel.

At this time, incident light incident through the portion where the open holes 71a1 to 71a4 of the upper micromirror 70a are formed may be incident on a corresponding portion of the lower micromirror 43, and the upper micromirror 70a and the lower micromirror may be incident. The maximum diffracted light is generated when the interval of 43 becomes an odd multiple of lambda / 4.

4 shows an embodiment of a GLV device as an optical modulation device to which the MEMS device described above is applied, or a conventional three-panel optical device using a piezoelectric diffraction type optical modulator of Samsung Electro-Mechanics.

The laser display 81 according to the embodiment of the prior art is used, for example, as a projector for large screens, in particular as a projector for digital images, or as an image projection apparatus of a computer.

As shown in Fig. 4, the laser display 51 has laser light sources 82R, 82G, and 82B of each color of red (R), green (G), and blue (B), and an optical axis image for each laser light source. Mirrors 84R, 84G, and 84B, which are provided in the Equipped.

The laser light sources 82R, 82G, and 82B each use lasers of R (wavelength 642 nm, light output approximately 3 W), G (wavelength 532 nm, light output approximately 2 W), and B (wavelength 457 nm, light output approximately 1.5 W), for example. Exit.

In addition, the laser display 81 includes a red (R) laser light, a green (G) laser light, and a blue (B) laser, each of which is light modulated by a GLV device or piezoelectric diffraction type optical modulators 88R, 88G, and 88B. It is equipped with a color synthesis filter 90, a spatial filter 92, a diffuser 94, a mirror 96, a galvano scanner 97, a projection optical system (lens group) 98 and a screen 99 for synthesizing light. have. The color combining filter 90 is composed of, for example, a dichroic mirror.

In the laser display 81 of the present embodiment, each of the RGB laser beams emitted from the laser light sources 82R, 82G, and 82B passes through each of the color tone light optical systems 86R, 86G, and the like via the mirrors 84R, 84G, and 84B. 86B) is incident on each GLV device or piezoelectric diffraction type optical modulators 88R, 88G, and 88B. Each laser light is a color-coded image signal, and is input in synchronization with the GLV device or the piezoelectric diffraction type optical modulators 88R, 88G, and 88B.

Further, each laser light is spatially modulated by diffraction by a GLV device or piezoelectric diffraction type optical modulators 88R, 88G, and 88B, and these three colors of diffracted light are synthesized by the color synthesis filter 90, and subsequently spaced. Only the signal component is taken out by the filter 92.

This RGB image signal is then reduced in the laser spectrum by the diffuser 94 and developed in space by the galvano scanner 97 in synchronization with the image signal via the mirror 96, and then onto the projection optical system 98. This projects onto the screen 99 as a full color image.

On the other hand, the display device using the diffraction type optical modulator described above is a device for outputting HDTV-quality image, 1080 pixels are arranged vertically to scan and display in the horizontal direction.

As shown in Fig. 5A, image data input in a typical HDTV or the like is aligned in the lateral direction. In the display device using the optical modulator, as shown in FIG. 5B, 1080 micro mirror elements are arranged in the longitudinal direction, and display 1080 image data while scanning in the horizontal direction.

At this time, as shown in the scanner trajectory diagram of the time-to-distance of FIG. 5C, the time intervals may be divided into A, B, and C. Time intervals A and B are forward scan intervals, and C is a reverse scan interval.

The forward scan section A can be viewed as a ready section where the scanner performs the forward scan but does not scan the actual image on the screen. In the time interval B, the scanner performs a forward scan, at which time the color image is scanned on the screen. On the other hand, in the time interval C, the scanner performs reverse scanning, in which case the color image is not scanned on the screen.

On the other hand, such a conventional line scanning method is designed to enable a fast deceleration during the reverse scan in order to display a color image on the screen.

However, the rapid deceleration during the reverse scan of the scanner described above causes high power consumption in terms of power, and causes the wear of the scanner to accelerate.

Accordingly, the present invention has been made to solve the above problems, the display device of the forward and reverse scanning type so that the color image is displayed in the reverse direction as well as in the reverse direction when scanning the diffracted light modulated by the diffractive optical modulator on the screen To provide that purpose.

The present invention for solving the above problems, a plurality of diffractive light modulator for generating a diffracted light having a plurality of diffraction orders by modulating the incident light according to an external control signal; An illumination optical unit configured to irradiate light corresponding to the plurality of light emitted from the plurality of light sources to the diffractive optical modulator; A schlieren optical unit for selecting and passing diffracted light having a desired order from diffracted light having a plurality of diffraction orders formed from the plurality of diffractive light modulators; And a scanning optical unit configured to perform forward and reverse line scanning on the screen of the diffracted light passing through the Schullen optical unit.

Now, a display device of forward and backward scanning according to a preferred embodiment of the present invention will be described in detail with reference to FIG. 6.

6 is a block diagram of a display device of the forward and backward scanning method according to an embodiment of the present invention.

Referring to FIG. 6, a raster scanning type display apparatus using a diffractive optical modulator according to an embodiment of the present invention includes a display optical system 102 and a display electronic system 104.

The display optical system 102 receives light from the laser light sources 106R, 106G, and 106B of each color of red (R), green (G), and blue (B), and the light emitted from each of the laser light sources (106R, 106G, and 106B). A plurality of illumination optics 108R, 108G, 108B, each of which illuminates linear light to irradiate each of the corresponding diffractive light modulators 110R, 110G, 110B with an elliptical narrow, long line-shaped light; A plurality of diffractive light modulators 110R, 110G, and 110B, which modulate the linear light irradiated from the units 108R, 108G, and 108B to generate diffracted light, and are respectively modulated by the diffractive light modulators 110R, 110G, and 110B. A light-receiving part 112 for condensing the diffracted light, and a schlieren for separating the diffracted light of R, G, and B condensed by the light-receiving part 112, and passing the diffracted light of a desired order among the diffracted light of the separated order The diffraction light passing through the Schlieren optics 114 and the Schlieren optics 114 is collected and the focused diffraction light is forward-reversed. A projection, and the scanning optical unit 116, and a display screen 118 to perform.

The display electromagnetic field 104 is connected to the laser light sources 106R, 106G, 106B, the diffractive light modulators 110R, 110G, 110B, and the projection and scanning optics 116.

A power supply unit (not shown) of the display electromagnetic field 104 provides power to the laser light sources 106R, 106G, and 106B. The laser light sources 106R, 106G, 106B emit laser light, the cross-sectional view of the emitted laser light being circular, and the intensity profile of the light has a Gaussian distribution.

Each of the illumination optics 108R, 108G, 108B converts the laser illumination emitted by the respective laser light sources 106R, 106G, 106B into elliptical, narrow, long linear light beams, and each corresponding diffractive light modulator. Focus on (110R, 110G, 110B).

When the elliptical narrow and long linear light is incident from the illumination optics 108R, 108G, and 108B, the diffraction type optical modulators 110R, 110G, and 110B (not shown) According to the control of the modulated linear light incident to generate the diffracted light is emitted, the light concentrator 112 condenses each light source having a plurality of orders of diffraction light and exits to the display screen 118 as a single light source do.

Then, when the diffraction light having various diffraction orders is incident, the schlieren optical unit 112 selectively passes diffraction light having a desired diffraction order. The plan view of the Schlieren optical unit 112 is composed of, for example, a Fourier lens (not shown) and a spatial filter or a dichroic filter (not shown). One is selected to pass the selected diffracted light.

The projection and scanning optics 116 are composed of a condenser lens 116a, a scanner 116b, and a projection lens 116c, and under the control of the display electromagnetic field 104, the scanner 116b receives incident diffracted light. Is performed on the screen 118 in a forward and backward direction to generate a color image. That is, the projection and scanning optics 116 display on the screen 118 while scanning a line image composed of a plurality of pixels, for example, 1080 pixels, passing through a spatial filter or a dichroic filter (not shown). To generate a color image, and also in the reverse direction, unlike the prior art, a line image is displayed on the screen 118 to generate a color image.

Here, the condenser lens 116a condenses the diffracted light such that the diffracted beam passing through the spatial filter or the dichronic filter (not shown) is focused on the screen 118. Of course, after the condenser lens 116a, a concave lens (not shown) may be further provided to condense the diffracted beam passing through the spatial filter or the dichroic filter (not shown), and then converted into parallel light to be projected onto the scanner 116b. It may be.

The scanner 116b is an X-axis scanner and the scanner 116b performs scanning of the incident line image from the left to the right of the screen 118 under the control of the scanner driving circuit (not shown) of the display electronic system 104, and then Scanning from right to left is repeated to repeat this operation, and the concept is well illustrated in FIG.

That is, FIG. 8 is a scanner trajectory diagram of time versus distance, which can be divided into a forward scan section F and a reverse scan section R, and the forward scan section is again a forward preparation section A, a forward image scanning section B, and a remaining section C. The reverse scan section may be further divided into a reverse preparation section A ', a reverse image scan section B', and a remaining section C '.

Here, the forward preparation section A is a section preparing to scan, the forward image scanning section B is a section for generating a color image by scanning a line image on the screen 118, and the remaining section C is a margin for performing a reverse scan. It's time.

Next, the reverse preparation section A 'is a section preparing to scan, the reverse image scan section B' is a section for generating a color image by scanning the line image on the screen 118 in the reverse direction, and the remaining section C 'is the forward direction again. Free time to perform the scan. In this case, as shown in FIG. 8, since the image projected on the screen 118 is an image proceeding from right to left, the diffractive light modulators 110R, 110G, and 110B also move from right to left in generating a line image. Line images must be created to match the reverse scan. The line image generation process of the diffractive optical modulators 110R, 110G, and 110B is controlled by an optical modulator driving circuit (not shown) of the display electromagnetic field 104.

According to the present invention as described above, it is possible to increase the light efficiency of time to increase the brightness when using the same light source or to have the effect of enabling the use of a low power light source when ensuring the same brightness.

That is, according to the present invention, the present invention is 94-96% idle injection compared to the existing 75% to 85% effective injection.

In addition, according to the present invention, the driving maximum acceleration of the scanning mirror can be lowered to lower the power consumption of the scanning mirror driver.

Claims (6)

A plurality of diffractive light modulators for generating diffracted light having a plurality of diffraction orders by modulating the incident light according to an external control signal; An illumination optical unit configured to irradiate light corresponding to the plurality of light emitted from the plurality of light sources to the diffractive optical modulator; A schlieren optical unit for selecting and passing diffracted light having a desired order from diffracted light having a plurality of diffraction orders formed from the plurality of diffractive light modulators; And And a scanning optical unit configured to perform forward and reverse line scanning on the screen of the diffracted light passing through the schlieren optical unit. The method of claim 1, The scanning optical unit, When line scanning is performed on the screen in the first direction of diffracted light passing through the Schlielen optical unit, a color line image is displayed on the screen, and then line scanning is performed in a second direction opposite to the first direction. A scanner to display a color line image when the screen is displayed; And Display device of the forward time-division scanning method using a diffraction type optical modulator comprising a scanner driving circuit for driving the scanner. The method of claim 1, The diffraction type optical modulator, A substrate having a recess formed in the central portion for providing an air space; And The bottom surface of each end is attached to both side regions outside the recessed portion of the substrate so that the center portion is spaced apart from the recessed portion of the substrate, and the piezoelectric material of the thin film is formed, including the thin film piezoelectric material layer. When voltage is applied to both sides of the material layer, the portions spaced apart from the depression are driven up and down, and the forward and reverse scanning method using a diffraction type optical modulator comprising a piezoelectric mirror layer for diffracting the incident beam. Display device. The method of claim 1, The diffraction type optical modulator, A plurality of open holes are formed in the element, and the upper micromirror on the upper surface of the element and the lower micromirror on the insulating layer form a step so that the incident light is modulated according to an external control signal to adjust the plurality of diffraction orders. Display device of the forward-direction scanning method using a diffraction type optical modulator, characterized in that the open-hole-based diffraction type optical modulator for generating a diffracted light having. The method of claim 1, The Schullen optical unit, A Fourier lens for dividing the diffracted light having a plurality of diffraction orders emitted from the diffraction optical modulator for each order; And And a filter for selecting and passing the diffracted light having a desired order from the diffracted light having a plurality of diffraction orders passing through the Fourier lens. The method of claim 1, And an optical modulator driving circuit configured to control the diffractive optical modulator to generate a line image modulated from the right side to the left side of the screen when the scanning optical unit performs reverse line scanning.

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