KR20110028827A - Laser projector display - Google Patents

Abstract

PURPOSE: A laser projector display is provided to maximize speckle reduction rate according to the drive frequency of the liquid crystal cell. CONSTITUTION: A laser projector display comprises a light source unit(10), a light uniformizing unit(20), and a speckle removal unit(40). The light source unit emits various light colors through multiple laser light sources. The light uniformizing unit uniformizes light emitted from the light source unit. The speckle removal unit comprises a liquid crystal cell of a matrix structure, and a portion through which a light pass and a portion for blocking light are arranged randomly.

Description

Laser projector display {Laser projector display}

FIELD OF THE INVENTION The present invention relates to laser projector displays, and more particularly to laser projector displays using lasers as light sources.

Recently, display apparatuses using various light sources have been manufactured. Among them, the laser light source has a wide color temperature, and thus the color of the display image can be expressed close to natural colors, and thus many applications have been attempted in the display field.

An object of the present invention is to provide a laser projector display capable of realizing excellent image quality.

As a first aspect for achieving the above technical problem, the present invention, the light source unit for emitting a plurality of color light through a plurality of laser light source; An optical homogenizer for making the light emitted from the light source into uniform light; And a liquid crystal cell having a matrix structure disposed between the light source unit and the light homogenizing unit, such that a portion of the liquid crystal cell that transmits light and a portion that blocks light is randomly arranged, and the arrangement changes with time. It is configured to include a speckle remover.

As a second aspect for achieving the above technical problem, the present invention, the light source unit for emitting a plurality of color light through a plurality of laser light source; An optical homogenizer for making the light emitted from the light source into uniform light; A liquid crystal cell having a matrix structure positioned between the light source unit and the light homogenizing unit, wherein the light transmitting part and the light blocking part randomly change with time; An image panel which generates an image using the light passing through the optical homogenizer; And a projection lens for magnifying and projecting the image generated by the image panel.

According to the present invention, in a display using a laser light source, the liquid crystal cell and the light uniformizing unit work together to reduce the speckle phenomenon with a simple configuration, and the effect of maximizing the speckle reduction rate according to the driving frequency of the liquid crystal cell is effective. It is.

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

While the invention allows for various modifications and variations, specific embodiments thereof are illustrated by way of example in the drawings and will be described in detail below. However, it is not intended to be exhaustive or to limit the invention to the precise forms disclosed, but rather the invention includes all modifications, equivalents, and alternatives consistent with the spirit of the invention as defined by the claims.

As shown in FIG. 1, a laser projector display includes a structure in which light emitted from a light source unit 10 including a laser light source is incident on the image panel 30 through a light homogenizing unit (integrator) 20. do.

The light source unit 10 emits a plurality of color lights through a plurality of laser light sources, and the light emitted from the light source unit 10 is formed as uniform light in the light homogenizer 20. The configuration of such a light source unit 10 will be described later.

Here, the optical homogenizer 20 may include at least one fly eye lens, and as illustrated, two fly eye lenses 21 and the fly eye lenses 21 facing each other. It may be made of a relay lens 22 to focus the light passing through the image panel 30.

As shown in FIG. 2, the fly's eye lens 21 includes a plurality of micro-lens 21a shapes each having a rectangular cross-sectional shape, and when light passes through each micro-lens 21a, two beams are different directions. The effective light source which is irradiated to the fly's eye lens 21 and formed by the fly's eye lens 21 has an intensity distribution in which a pair of light sources are formed by each of the microlenses 21a.

A liquid crystal cell 41 having a matrix structure is provided between the light source unit 10 and the light homogenizing unit 20. The liquid crystal cell 41 has a portion (on) and light transmitting light as shown in FIG. 3. The portion blocking (off) is randomly arranged, and this portion turned off changes over time. As such, the randomly arranged structure is changed according to time, thereby driving the liquid crystal cell 41.

At this time, it is advantageous that the portion of the liquid crystal cell 41 that transmits light and the portion that blocks light have the same area.

In applying a laser light source in a display, since the laser has coherence that maintains the same phase in time and space, a phenomenon called speckle may occur when the laser is used for the display.

This speckle phenomenon occurs when coherent light, such as laser light, is reflected from the surface of an object and is scattered by the roughness of the surface and viewed in a detector (e.g. a human eye) having a defined aperture. It is a phenomenon.

That is, the speckle phenomenon is a phenomenon that is distinguished from spots caused by changes in an image or beam intensity distribution due to defects of an optical system through which laser light passes.

Therefore, in a display using a laser, speckle or hot spot speckles may be generated as a kind of interference fringe on the screen.

This speckle phenomenon can be reduced or eliminated by the liquid crystal cell 41 as described above. That is, the liquid crystal cell 41 that changes in time by randomly arranging a portion that transmits light (on) and a portion that blocks light (off) is a spec that can reduce the speckle together with the optical homogenizer 20. The clock removal unit 40 may be configured.

That is, the phase difference occurs in the laser light while the laser light emitted from the light source unit 10 passes through the light transmitting portion (on) and the light blocking portion (off) of the liquid crystal cell 41.

As described above, the light passing through the liquid crystal cell 41 passes through the fly's eye lens 21 forming the optical homogenizer 20, and due to the matrix structure of the liquid crystal cell 41, the beam a and the portion of the off-state cell are separated from each other. d) fails to enter the image panel and only the (b and c) beams that are part of the on-state cells enter the image panel.

Of these, the angle of the beam reaching the image panel 30 passes through the liquid crystal cell 41 of the matrix structure, and then the light passing through the liquid crystal cell 41 in a specific on state, that is, only b and c is the image panel ( 30).

Since the cells in which the liquid crystal cell 41 of the matrix structure is turned on / off with time continue to change, the angle of the beam reaching the image panel 30 will also change with time. The angles of incident beams over time create different speckle patterns on the screen, which can be superimposed to reduce speckle.

On average, a person can react to changes in vision at about 50ms. That is, if there is a change within 50ms, the average person will not notice it.

Therefore, if the speckle patterns overlap each other within 50 ms (20 Hz), which is a time when a human can recognize a change, the human vision may feel that the speckle pattern is reduced.

For example, if n screens overlap each other, the human eye may feel that the speckle is reduced to 1 / (n) ^1/2 .

Therefore, if four speckle patterns overlap within 50 ms, the viewer may feel that the speckle phenomenon is reduced to 1/2. At this time, the frequency is 80 Hz. When the liquid crystal cell 41 of the speckle remover 40 is driven at 80 Hz, the viewer may feel that the speckle phenomenon is reduced by half.

In addition, if the driving frequency of the liquid crystal cell 41 becomes 180 Hz, nine patterns may overlap within 50 ms, and the viewer may feel that the speckle phenomenon is reduced to 1/3.

Therefore, if the reaction speed of the liquid crystal cell 41 is allowed, if the liquid crystal cell 41 is driven at the highest possible frequency, the viewer may feel that the speckle phenomenon is further reduced accordingly.

One specific embodiment of such a laser projector display is shown in FIG. 4. 4 shows an example of a single-plate projector display.

The light source unit 10 includes a red (R) laser light source 11, a green (G) laser light source 12, and a blue (B) laser light source 13, and each of these light sources 11, 12, 13. The focusing lens 14 may be provided.

Each light source 11, 12, 13 constituting the light source unit 10 is synthesized by white light by the color combining units 15, 16, and the color combining unit selectively selects the color of each of the light sources 11, 12, 13. Two dichroic mirrors 15 and 16 that transmit or reflect through can be used.

As such, the light synthesized with the white light may be incident to the image panel 30 through the color wheel 50. The light passing through the color wheel 50 is incident on the image panel 30 through the TIR prism 60 and then reflected back to the screen, and is projected onto the screen by projecting a lens to enlarge and project the image generated by the image panel 30. 70 may be provided.

On the other hand, the image panel, any one of a micro mirror device (DMD), LCoS, and LCD can be used.

In this case, the above-described light homogenizer 20 and the speckle remover 40 are positioned between the color wheel 50 and the TIR prism 60 to uniformly mix the light to the laser light sources 11, 12, 13. It is to mitigate the speckle phenomenon.

In addition, each portion of the light path may be provided with an illumination lens 80 consisting of one or more lenses. In the present embodiment, the illumination lens 80 is provided between the light source unit 10 and the color wheel 50 and between the color wheel 50 and the speckle removing unit 40.

5 shows an example of a three-panel projector display.

Also in the present embodiment, the light source unit 10 includes a red (R) laser light source 11, a green (G) laser light source 12, and a blue (B) laser light source 13, and each of the light sources 11, 12 and 13 may be provided with a focusing lens 14.

Each light source 11, 12, 13 constituting the light source unit 10 is synthesized by white light by the color combining units 15, 16, and the color combining unit selectively selects the color of each of the light sources 11, 12, 13. Two dichroic mirrors 15 and 16 can be used which transmit or reflect through the same, which is the same as the single plate type.

The light synthesized as described above passes through the light homogenizer 20 and the speckle remover 40 and is incident to the PBS array 90. The light incident to the PBS array 90 is thus incident on the X prism 34. The light is separated into respective colors and incident on the panels 31, 32, and 33.

That is, the three sides of the cube-shaped X prism 34 are each provided with a red (R) image panel 31, a green (G) image panel 32, and a blue (B) image panel 33. The light synthesized above by 34 is separated again, is incident on each panel 31, 32, 33 and reflected again.

In this way, the light reflected from each panel 31, 32, 33 is projected onto the screen through the projection lens 70 again through the PBS array 90.

In addition, each portion of the light path may be provided with an illumination lens 80 consisting of one or more lenses. In the present embodiment, the illumination lens 80 is provided between the light source unit 10 and the speckle removing unit 40.

The above embodiment is an example for explaining the technical idea of the present invention in detail, and the present invention is not limited to the above embodiment, various modifications are possible, and various embodiments of the technical idea are all protected by the present invention. It belongs to the scope.

1 is a block diagram illustrating the principle of the present invention.

2 is a schematic diagram showing the action of a fly's eye lens;

3 is a schematic view showing an example of a random pattern of a liquid crystal cell.

4 is a block diagram showing an embodiment of the present invention.

5 is a configuration diagram showing another embodiment of the present invention.

Claims (10)

A light source unit emitting a plurality of color lights through the plurality of laser light sources; An optical homogenizer for making the light emitted from the light source into uniform light; And Located between the light source and the light homogenizing portion, the liquid crystal cell of the matrix structure is provided, the portion of the liquid crystal cell that transmits light and blocks the light is randomly arranged, the arrangement is changed over time Laser projector display, characterized in that it comprises a clip removal unit. The laser projector display of claim 1, wherein the light transmitting portion and the light blocking portion of the liquid crystal cell of the speckle removing portion have the same area. The laser projector display according to claim 1, wherein the frequency at which the arrangement changes with time is 80 Hz or more. The method of claim 1, wherein the light homogenizing unit, At least one fly eye lens; And And a relay lens for focusing the light passing through the fly's eye lens onto the image panel. The method of claim 1, A color synthesizing unit for synthesizing a plurality of color lights of the light source unit to the same optical axis; An image panel which generates an image using the light passing through the optical homogenizer; And at least one of projection lenses for magnifying and projecting an image generated by the image panel. The laser projector display of claim 5, wherein the color combining unit comprises a plurality of dichroic mirrors. The laser projector display of claim 5, wherein the image panel is any one of a DMD, an LCoS, and an LCD. A light source unit emitting a plurality of color lights through the plurality of laser light sources; An optical homogenizer for making the light emitted from the light source into uniform light; A liquid crystal cell having a matrix structure positioned between the light source unit and the light homogenizing unit, wherein the light transmitting part and the light blocking part randomly change with time; An image panel which generates an image using the light passing through the optical homogenizer; And And a projection lens for magnifying and projecting an image generated by the image panel. The laser projector display according to claim 8, wherein the light transmitting portion and the light blocking portion of the liquid crystal cell of the speckle removing portion have the same area. The method of claim 8, wherein the light homogenizing unit, At least one fly eye lens; And And a relay lens for focusing the light passing through the fly's eye lens onto the image panel.

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