KR100590327B1 - Optical system using digital micromirror - Google Patents

Abstract

The present invention is directed to an optical system using a digital micromirror. An optical system using a digital micromirror according to the present invention includes: a light source for emitting a beam; A color filter selectively transmitting only a predetermined wavelength of a beam generated from the light source; A rod lens for passing a beam of a predetermined wavelength selected by the color filter; A mirror reflecting the beam passed through the rod lens; A first prism to which the beam reflected from the mirror is incident; A DMD totally reflecting the beam incident on the first prism; A second prism for emitting a beam totally reflected from the DMD; A projection lens for projecting the beam emitted from the second prism onto a screen; It is characterized in that it comprises a wedge lens provided between the first prism and the DMD.

The optical system using the digital micromirror according to the present invention, in the optical system using a micromirror made of a diamond-shaped pixel, the uneven linear shape appearing on the screen by the diamond-shaped micromirror can be alleviated and displayed. .

Micromirrors, Wedge Lenses, Diamond Pixels

Description

Optical system using digital micromirror {OPTICAL UNIT USING OF DIGITAL MICROMIRROR}

1 is a view schematically showing the structure of an optical system using a general digital micromirror.

FIG. 2 schematically illustrates the DMD structure of FIG. 1. FIG.

3 is a view illustrating a micromirror configured in the form of the diamond pixel of FIG. 2.

FIG. 4 shows the alignment represented by the micromirror having the diamond pixel form of FIG. 3. FIG.

5 is a view schematically showing the structure of an optical system using a digital micromirror according to the present invention.

6 schematically illustrates the structure of the prism of FIG.

7 shows the rotation of a wedge lens according to the invention.

8 is displayed on the screen by the diamond-shaped micromirror according to FIG.

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

50 --- light source 51 --- color filter

52 --- Road Lens 53 --- Mirror

54 --- First Prism 55 --- DMD

56 --- Second Prism 57 --- Projection Lens

58 --- wedge lens

The present invention relates to an optical system using a digital micromirror, particularly in an optical system using a micromirror in the form of a diamond-shaped pixel, the uneven linear shape appearing on the screen by the diamond micromirror can be displayed to be relaxed It is an optical system using a digital micromirror.

Recently, large screen and high-definition display devices have emerged as one of the most important issues, and to date, projection TVs and projectors are representatively developed and commercialized as such large screen displays.

In this case, a projection TV and a projector commonly include a device called an optical engine, and within the optical engine, a cathode ray tube (CRT), a liquid crystal display (LCD), and a digital micromirror device (DMD) are used to display signal-processed image information. Display elements such as these are used.

In recent years, such display devices have become smaller and lighter, and thus, a liquid crystal display ("LCD") and a digital micromirror device ("DMD") are more widely used than heavy and thick CRTs. do.

The liquid crystal display can be classified into a transmissive type and a reflective type, and most of the currently-sold types have a transmissive type. The rotation angle of the incident polarization changes with respect to the electrical variation given from the outside, and the light intensity increases as the polarizing plate passes through a specific direction. It is a kind of light valve display element to change.

However, since the CRT and the LCD are driven by an analog signal, the digital signal is converted into an analog signal and displayed at the final stage of signal processing, while the DMD converts the digital signal into a pulse width modulation (PWM) without D / A conversion. Since it is driven by using, there is an advantage that can eliminate the error that can occur in the D / A conversion to the maximum, has recently been spotlighted as a display display element.

The DMD is used in a digital light processing ("DLP") system, and is a kind of optical switch that acts to change the reflection angle of the light to two modes by changing the fine mirror +10 to -10 degrees Display element. The intensity of the light is adjusted to take time to send the light at a particular angle.

In addition, the DLP system is classified into a direct reflection method and a total internal reflection (“TIR”) prism method according to a method of incidence and exit of light into the DMD.

However, the direct reflection method cannot realize the size of the optical system thinner than that of the prism method, and thus, the prism type optical system has been recently used in many cases.

1 is a view schematically showing the structure of an optical system using a general digital micromirror. As shown therein, the light source 10 emitting the beam; A color filter (11) for selectively transmitting only a predetermined wavelength of the beam generated by the light source (10); A rod lens 12 for passing a beam of a predetermined wavelength selected by the color filter 11; A mirror (13) for reflecting the beam passing through the rod lens (12); A first prism (14) into which the beam reflected from the mirror (13) is incident; A DMD (15) for total reflection of the beam incident on the first prism (14); A second prism (16) for emitting a beam totally reflected by the DMD (15); And a projection lens 17 for projecting the beam emitted from the second prism 16 onto the screen.

Here, the light projected by the projection lens 17 is imaged on a screen not shown.

The first prism 14 and the second prism 16 are combined by a rectangular prism using total reflection and a prism for generating another total reflection at a specific angle.

The angle of the totally reflected surface of the first prism 14 is adjusted to allow light to enter the DMD 15 using total reflection. This is because a plurality of micromirrors installed in the DMD 15 are rotated within a predetermined angle range so that the reflecting surface of the micromirror is determined in an oblique direction.

That is, the reflecting surface angle of the first prism 14 through which the incident light is totally reflected so that the incident light incident on the first prism 14 is incident on the DMD 15 in the oblique direction rather than vertically by the first prism 14. Is set.

The DMD 15 is provided on the rear surface of the second prism 16 to totally reflect incident light from the first prism 14 to the second prism 16. The second prism 16 is provided at a predetermined interval from the first prism 14. At this time, a space in which air exists between the first prism 14 and the second prism 16 is generated.

By this space, the second prism 16 causes the incident light totally reflected from the DMD 15 to travel toward the projection lens without being reflected in a specific direction or another direction.

FIG. 2 is a diagram schematically illustrating the DMD structure of FIG. 1. As shown in the drawing, the DMD includes a plurality of electrodes 22 provided in a predetermined portion on the black board 21, a micromirror 23 for reflecting light emitted from the lamp at a predetermined angle; And a shaft 24 for supporting the micromirror 23.

The electrode 22 is provided on the black board 21 to move the shaft 24 using an electrostatic field generated by a voltage applied from the outside.

FIG. 3 is a diagram illustrating a micromirror configured in the form of the diamond pixel of FIG. 2. As shown in the drawing, the micromirror 23 is manufactured in the form of a fine diamond-shaped pixel of 16 μm, rotated by ± 10 degrees by the axis 24 to project light emitted from the light source 10 at a predetermined angle. Reflected on the screen through the lens (17).

In other words, the optical path between the lamp 10 and the screen is rotated by rotating the diamond-shaped micromirror 23 within ± 10 degrees in the vertical direction by using the electrostatic action generated by an externally applied voltage. Controlled.

That is, the screen may be turned on / off at high speed by using the micromirror 23.

FIG. 4 is a diagram illustrating the linearity represented by the micromirror having the diamond pixel type of FIG. 3. As shown in the drawing, the micro-mirror having the diamond pixel type has a problem of appearing in a rugged linear shape rather than a linear shape on a line when projected onto a screen.

The present invention provides an optical system using a digital micromirror in the optical system using a micromirror in the form of a diamond-shaped pixel, so that the uneven linear shape appearing on the screen by the diamond-shaped micromirror can be alleviated and displayed. Has its purpose.

Optical system using a digital micromirror according to the present invention to achieve the above object,

A light source for emitting a beam;

A color filter selectively transmitting only a predetermined wavelength of a beam generated from the light source;

A rod lens for passing a beam of a predetermined wavelength selected by the color filter;

A mirror reflecting the beam passed through the rod lens;

A first prism to which the beam reflected from the mirror is incident;

A DMD totally reflecting the beam incident on the first prism;

A second prism for emitting a beam totally reflected from the DMD;

A projection lens for projecting the beam emitted from the second prism onto a screen;

It is characterized in that it comprises a wedge lens provided between the first prism and the DMD.

Here, in particular, the wedge lens may be provided between the second prism and the projection lens instead of between the first prism and the DMD.

In particular, the wedge lens is characterized in that the height of both sides is formed differently.

In particular, the wedge lens is characterized in that it rotates 180 degrees or 360 degrees.

Here, in particular, the wedge lens is characterized in that the curvature of the line reflected from the DMD and projected on the screen in a circular shape during the rotation of 180 or 360 degrees.

According to the present invention, in the optical system using a micromirror in the form of a diamond-like pixel, the uneven linear shape appearing on the screen by the diamond-shaped micromirror can be alleviated and displayed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

5 is a view schematically showing the structure of an optical system using a digital micromirror according to the present invention. As shown therein, the light source 50 emits a beam; A color filter (51) for selectively transmitting only a predetermined wavelength of the beam generated by the light source (50); A rod lens 52 for passing a beam of a predetermined wavelength selected by the color filter 51; A mirror (53) for reflecting the beam passing through the rod lens (52); A first prism (54) into which the beam reflected from the mirror (53) is incident; A DMD (55) which totally reflects the beam incident on the first prism (54); A second prism (56) for emitting a beam totally reflected from the DMD (55); A projection lens (57) for projecting the beam emitted from the second prism (56) onto a screen; And a wedge lens 58 provided between the first prism 54 and the DMD 55.

Here, the light projected by the projection lens 57 is imaged on a screen not shown.

The first prism 54 and the second prism 56 are combined with a rectangular prism using total reflection and a prism for generating another total reflection at a specific angle.

FIG. 6 is a view schematically illustrating the structure of the prism of FIG. 5. As shown in the drawing, the first prism 54 and the second prism 56 are bonded to the prism for generating a right angle prism and another total reflection at a specific angle so as to give a small air gap so that total reflection does not occur when incident. It is configured to cause total reflection when reflecting back.

The angle of the totally reflected surface of the first prism 54 to allow light to enter the DMD 55 using total reflection is adjusted. This is because a plurality of micromirrors installed in the DMD 55 are rotated within a predetermined angle range so that the reflecting surface of the micromirror is determined in a diagonal direction.

That is, the reflection surface angle of the first prism 54 through which the incident light is totally reflected so that the incident light incident on the first prism 54 is incident on the DMD 55 by the first prism 54 in an oblique direction rather than vertically. Is set.

The DMD 55 is provided on the rear surface of the second prism 56 to totally reflect incident light from the first prism 54 to the second prism 56. The second prism 56 is provided at a predetermined interval from the first prism 54. At this time, a space in which air exists between the first prism 54 and the second prism 56 is generated.

By this space, the second prism 56 causes the incident light totally reflected from the DMD 55 to travel toward the projection lens without being reflected in a specific direction or another direction.

Referring to FIG. 2, the DMD 55 includes a plurality of electrodes 22 provided at predetermined portions on the black board 21 and a micromirror for reflecting light emitted from a lamp at a predetermined angle. ) And a shaft (24) for supporting the micromirror (23).

The electrode 22 is provided on the black board 21 to move the shaft 24 using an electrostatic field generated by a voltage applied from the outside.

7 is a view showing the rotation of the wedge lens according to the present invention. As shown in the drawing, the wedge lens 58 has a different structure from both sides of the lens, and rotates 180 degrees.

That is, the angle at which the light is refracted also varies depending on the position of the wedge lens 58 having different heights.

Thus, the angle of the beam reflected from the micromirror while the wedge lens 58 rotates also changes with time.

8 is a diagram displayed on the screen by the diamond-shaped micromirror according to FIG. As shown in the drawing, the micromirror 23 is manufactured in the form of a fine diamond-shaped pixel of 16 μm, and rotates by ± 10 degrees by the axis 24 to project the light emitted from the light source at a predetermined angle. On the screen.

The light emitted from the light source 51 is continuously irradiated onto the front surface of the DMD 55 and absorbed by the absorption plate without being reflected by the projection lens 57 by the micromirror set at an initial predetermined angle so that the screen is black. It becomes a state.

At this time, by applying a voltage from the outside to generate an electrostatic field on the plurality of electrodes 22 provided on the black board 21, the shaft 24 connected between the plurality of adjacent electrodes 22 is a plurality of The electrostatic field generated by the electrode 22 is rotated at a predetermined angle.

In addition, the micromirror 23 supported on the shaft 24 rotates at any one of +10 degrees to -10 degrees by the shaft 24 rotating at a predetermined angle to the micromirror 23. The light totally reflected by the light is reflected toward the projection lens 57.

Light incident on the projection lens 57 is transmitted to the screen through the projection lens 57 so that the state of the screen becomes a white state.

In other words, the optical path between the light source and the screen is controlled by rotating the diamond-shaped micromirror within ± 10 degrees in the vertical direction by using an electrostatic field action generated by an externally applied voltage.

That is, the screen may be turned on / off at a high speed by using the micromirror.

When the wedge lens 58 is repeatedly rotated 180 degrees or 360 degrees, and the micromirror of the DMD 55 is reflected toward the projection lens 57 while moving at a predetermined angle, diamonds appearing on the screen The rugged alignment of the shaped micromirror is displayed in a curved form, resulting in smoother lines.

Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, in the optical system using the digital micromirror according to the present invention, in the optical system using the micromirror in the form of a diamond-shaped pixel, the rugged linear shape appearing on the screen is alleviated by the diamond micromirror. To be displayed.

Claims (5)

A light source for emitting a beam; A color filter selectively transmitting only a predetermined wavelength of a beam generated from the light source; A rod lens for passing a beam of a predetermined wavelength selected by the color filter; A mirror reflecting the beam passed through the rod lens; A first prism to which the beam reflected from the mirror is incident; A DMD totally reflecting the beam incident on the first prism; A second prism for emitting a beam totally reflected from the DMD; A projection lens for projecting the beam emitted from the second prism onto a screen; Optical system using a digital micromirror, characterized in that it comprises a wedge lens is formed between the height of both sides provided between the first prism and the DMD. The method of claim 1, The wedge lens may be provided between the second prism and the projection lens instead of between the first prism and the DMD, the optical system using a digital micromirror. delete The method of claim 1, The wedge lens is an optical system using a digital micromirror, characterized in that for rotating 180 degrees or 360 degrees. The method of claim 4, wherein Optical system using a digital micromirror, characterized in that the curve of the line reflected from the DMD and projected on the screen according to the time while the wedge lens rotates 180 degrees or 360 degrees as a circle.

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