KR20090102091A - Laser projector - Google Patents

Abstract

PURPOSE: A laser projector is provided to perform a clear screen by spatially changing a polarizing direction of a laser light. CONSTITUTION: A laser projector(200) includes an optical lighting system(210), a display panel(220), and a projection system(230). The optical lighting system generates and emits a laser light. The display panel projects an image on a screen(240) by using the laser light emitted in the optical lighting system. The projection system projects the laser light which passes the display panel on the screen. A polarizing conversion region is formed in the projection system. The polarizing conversion region converts a part of a first polarizing component of the laser light into a second polarizing component. The polarizing conversion region reduces a speckle.

Description

Laser projector

The present invention relates to an image projection apparatus, and more particularly, to a laser projector using laser light.

Recently, due to the rapid development of the display field, consumers want to see miniaturization and bright and clear images on a larger screen. As one of means for satisfying the needs of consumers, the development of a display device using laser light is actively progressing.

1 is a block diagram of a laser display system of the prior art.

Using a laser as a light source has the advantage that the color of the image is clear, close to pure color, and has a wide range of color reproduction, and a high contrast allows a clear image to be obtained.

Referring to FIG. 1, a projection display device using a laser as a light source uses a laser 11 as a light source instead of a lamp, and irradiates the laser panel to the display panel 13 by the illumination optical system 12.

The display panel 13 displays an image by adjusting the amount of light by an electrical signal, and displays the image on a large screen by projecting the image onto the screen 15 by the projection optical system 14.

Such a laser display device of the prior art increases the color clarity by using a laser, can display an image that is excellent in color reproducibility, close to natural colors, and can reproduce clear picture quality due to high contrast.

However, due to the coherence characteristic of the laser, the interference of the laser is generated on the screen, and the speckle phenomenon appears as if the small particles are sparkling on the screen.

This speckle phenomenon reduces the contrast and resolution as a factor of degrading the image quality.

In order to eliminate the speckle phenomenon, an optical element such as a diffuser may be used, but the diffuser has a problem in that the transmittance of light is significantly reduced.

The present invention has been made to solve the above problems, and an object thereof is to provide a laser projector capable of efficiently removing speckles by spatially changing the polarization direction of laser light.

A laser projector according to the present invention for achieving the above object comprises an optical illumination system for generating and emitting laser light; A display panel for projecting an image on a screen using laser light emitted from the optical illumination system; And a projection system that focuses the laser light passing through the display panel and projects the laser light onto the screen, wherein the projection system converts a part of the first polarization component of the laser light into a second polarization component to reduce speckle. At least one polarization conversion region is formed.

The projection system includes first and second projection lenses for focusing the laser light; And an aperture stop formed between the first and second projection lenses and having the polarization conversion regions formed therein.

In this case, the polarization conversion regions are retardation plates or polarization conversion films, and may be attached to one region of the aperture through which the laser light of the aperture stop passes.

That is, the polarization conversion areas are attached to the aperture stop with a size 1/2 of the total area of the aperture, and rotate the first polarization component by 0 °; And a second region attached to the aperture stop with a size 1/2 of the total area of the aperture, and rotating the first polarization component by 90 °.

The first and second polarization conversion areas may be attached to the aperture stop with a size 1/4 of the total area of the aperture, and rotate the first polarization component by 0 °. A second region attached to the aperture stop with a size 1/4 of the total area of the aperture, and rotating the first polarization component by 90 °; A third region attached to the aperture stop with a size 1/4 of the total area of the aperture and rotating the first polarization component by 0 °; And a fourth region attached to the aperture stop with a size 1/4 of the total area of the aperture and rotating the first polarization component by 90 °, wherein the first to fourth regions alternately have the aperture. It can be attached to the aperture.

Laser projector according to the present invention has the effect of providing a clear picture quality by removing the speckle by spatially changing the polarization direction of the laser light.

1 is a block diagram of a laser display system of the prior art.

Figure 2 is a schematic diagram of an embodiment of a laser projector according to the present invention.

3 is a view showing a projection system having polarization conversion regions according to the present invention.

4 is a front view of a first embodiment showing an aperture stop having polarization conversion regions according to the present invention.

5 is a front view of a second embodiment showing an aperture stop having polarization conversion regions according to the present invention.

<Description of Major Symbols in Drawing>

210: optical illumination system 211: laser light source

212: first condenser lens 213: collimating lens

214: dichroic mirror 215: second condensing lens

216: integrator 220: display panel

220a: reflector 230: projection system

231: first projection lens 232: aperture aperture

233: second projection lens 240: screen

Other objects, features and advantages of the present invention will become apparent from the following detailed description of the embodiments.

Preferred embodiments of the projector according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a schematic diagram of an embodiment of a laser projector according to the present invention.

2, the laser projector 200 according to the present invention includes an optical illumination system 210, a display panel 220, and a projection system 230.

Hereinafter, the laser projector 200 according to the present invention may be configured to include other than the above-described components as necessary, but other than the above-described components are not directly related to the present invention, For simplicity, a detailed description thereof is omitted below.

On the other hand, it should be noted that the components may be configured by combining two or more components into one component, or one component may be subdivided into two or more components as necessary when implemented in actual applications.

Hereinafter, the components of the laser projector 200 according to the present invention will be described.

The optical illumination system 210 includes laser light sources 211a, 211b, and 211c, first condensing lenses 212a, 212b, and 212c, collimating lenses 213a, 213b, and 213c, and dichroic. The mirrors 214a and 214b, the second condensing lens 215, and the integrator 216 are included.

The laser light sources 211a, 211b, and 211c are laser diodes, which generate red (R), green (G), and blue (B) laser light and emit the same.

The first condensing lenses 212a, 212b, and 212c condense the light emitted from the laser light sources 211a, 211b, and 211c.

The collimating lenses 213a, 213b, and 213c convert light collected by the first condensing lenses 212a, 212b, and 212c into parallel light.

The dichroic mirrors 214a and 214b are mirrors capable of selectively reflecting or transmitting only light having a specific wavelength to obtain light of a desired wavelength band, and generally use interference of light.

In the dichroic mirrors 214a and 214b, for example, the first dichroic mirror 214a is positioned at a position where the red 211a laser light and the blue 211c laser light intersect, and the green is also green. The second dichroic mirror 214b may be positioned at a position where the laser light and the blue 211c laser light intersect each other.

In this case, as shown in FIG. 2, the first dichroic mirror 214a may transmit the red 211a laser light and reflect the green 211b laser light and the blue 211c laser light.

The second dichroic mirror 214b may reflect green 211b laser light and transmit blue 211a laser light.

As such, the red 211a laser light, the green 211b laser light, and the blue 211c laser light pass through the two dichroic mirrors 214a and 214b, and are synthesized and imaged in various colors according to the image to be formed. Are synthesized.

The second condenser lens 215 condenses the laser light synthesized by the dichroic mirrors 214a and 214b again.

The integrator 216 shapes the laser light incident from the second condenser lens 215 into a shape having a uniform brightness.

In this case, the integrator 216 may be formed of a rod-shaped rod lens or a box-shaped mirror, a funnel, a trapezoidal optical funnel, or the like.

Also, in the present invention, a fly's eye lens may be used instead of the integrator 216.

The display panel 220 selectively transmits or reflects the laser light reflected from the integrator 216 through the reflector 220a to form an image.

The display panel 220 forms a reflective image such as a digital micro mirror device, a liquid crystal on silicon (LCS), or the like, which forms an image by selectively reflecting incident light on a pixel-by-pixel basis. Unit, and a transmissive image forming unit such as a transmissive liquid crystal display element for forming an image by selectively transmitting incident light in units of pixels.

The projection system 230 enlarges and projects the image formed by the display element 220 onto the screen 300, and converts a part of the first polarization component of the laser light into the second polarization component according to the present invention to reduce speckle. At least one polarization conversion region is formed.

Hereinafter, a projection system 230 having polarization conversion regions according to the present invention will be described in detail with reference to FIG. 3.

3 is a view showing a projection system having polarization conversion regions according to the present invention.

Referring to FIG. 3, the projection system 230 according to the present invention includes first and second projection lenses 231 and 233 and an aperture stop 232.

The first and second projection lenses 231 and 233 enlarge and project the image formed by the display element 220 onto the screen 240.

The aperture stop 232 adjusts the amount of laser light that has passed through the first projection lens 231 of the aperture.

In the aperture of the aperture stop 232 as described above, polarization conversion regions are formed to reduce the speckle according to the present invention.

The polarization conversion regions may be formed of a retardation plate or a polarization conversion film, and are attached to one region of the aperture through which the laser light of the aperture stop 232 passes.

Hereinafter, polarization conversion regions according to the present invention will be described in detail with reference to FIGS. 4 and 5.

4 is a front view of a first embodiment showing an aperture stop having polarization conversion regions according to the present invention.

5 is a front view of a second embodiment showing an aperture stop having polarization conversion regions according to the present invention.

First, referring to FIG. 4, the polarization conversion regions according to the first exemplary embodiment of the present invention may include a first region for rotating P polarization component (or S polarization component) of laser light emitted from the display panel 220 by 0 °. 232a and a second region 232b for rotating the P-polarized component (or S-polarized component) by 90 °.

That is, as shown in FIGS. 4A and 4B, the first and second regions 232a and 232b respectively correspond to an area of 1/2 of the aperture area of the aperture stop 232. It is formed in size.

When the P-polarized component (or S-polarized component) of the laser light passes through the first region 232a, the P-polarized component (or S-polarized component) does not change as the polarization direction is rotated by 0 °. S polarized light component) is emitted.

However, when the P-polarized component (or S-polarized component) of the laser light passes through the second region 232b, the P-polarized component (or S-polarized component) becomes S-polarized component (or P polarized light component) and is emitted.

Next, referring to FIG. 5, the polarization conversion regions according to the second exemplary embodiment of the present invention may be configured to rotate P polarization components (or S polarization components) of the laser light emitted from the display panel 220 by 0 °. One region 232a, a second region 232b for rotating the P-polarized component (or S-polarized component) by 90 °, and a third region 232a for rotating the P-polarized component (or S-polarized component) by 0 ° ') And the fourth region 232b' for rotating the P-polarized component (or S-polarized component) by 90 degrees.

That is, as shown in FIG. 5, the first to fourth areas 232a, 232a ′, 232b, and 232b ′ have sizes corresponding to 1/4 of the aperture area of the aperture stop 232, respectively. Is formed.

When the P-polarized component (or S-polarized component) of the laser light passes through the first and third regions 232a and 232a ', the P-polarized component (or S-polarized component) changes as the polarization direction is rotated by 0 °. P polarized light component (or S polarized light component) is emitted.

However, when the P-polarized component (or S-polarized component) of the laser light passes through the second and fourth regions 232b and 232b ', the P-polarized component (or S-polarized component) is rotated by 90 °. Therefore, it changes into S-polarized component (or P-polarized component), and is emitted.

As described above, the polarization direction of the laser light is continuously changed by the first and second regions 232a and 232b of FIG. 4 and the first to fourth regions 232a, 232a ', 232b and 232b' of FIG. 5. The change in the polarization direction as described above results in different interference fringes.

When the speckle patterns generated by the continuous interference fringe change are shown as the average of the speckle patterns when viewed on the screen 240, when the user views an image through the screen, the screen 240 is displayed on the screen 240. The speckle shown will appear to be reduced.

It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit and essential features of the present invention. For example, it will be very easy for those skilled in the art to use the above-described embodiments in combination with each other.

Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative.

The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

Claims (5)

An optical illumination system for generating and emitting laser light; A display panel for projecting an image on a screen by using the laser light emitted from the optical illumination system; And And a projection system that focuses the laser light passing through the display panel and projects the laser light onto the screen. And at least one polarization conversion region in the projection system to reduce a speckle by converting a part of the first polarization component of the laser light into a second polarization component. The method of claim 1, wherein the projection system, First and second projection lenses focusing the laser light; And an aperture stop formed between the first and second projection lenses and having the polarization conversion regions formed therein. The method of claim 2, The polarization conversion regions, as a retardation plate or a polarization conversion film, the laser projector, characterized in that attached to one region of the aperture through which the laser light of the aperture stop. The method of claim 3, wherein the polarization conversion regions, A first region attached to the aperture stop having a size 1/2 of the total area of the aperture and rotating the first polarization component by 0 °; And And a second area attached to the aperture stop with a size 1/2 of the total area of the aperture, and rotating the first polarization component by 90 °. The method of claim 3, wherein the polarization conversion regions, A first region attached to the aperture stop with a size 1/4 of the total area of the aperture and rotating the first polarization component by 0 °; A second region attached to the aperture stop with a size 1/4 of the total area of the aperture and rotating the first polarization component by 90 °; A third region attached to the aperture stop with a size 1/4 of the total area of the aperture and rotating the first polarization component by 0 °; And And a fourth region attached to the aperture stop with a size 1/4 of the total area of the aperture, and rotating the first polarization component by 90 °. And the first to fourth regions are alternately attached to the aperture stop.