KR101315981B1 - Projector - Google Patents

Abstract

The present invention relates to a projector that provides clear picture quality by removing speckle. The projector includes: a light source unit including an R light source for irradiating red light, a G light source for irradiating green light, and a B light source for irradiating blue light; A beam shaping lens for dividing the light emitted from the G light source; A color combining unit for synthesizing the light emitted from the R light source, the G light source, and the B light source to the same optical axis; A fly's eye lens shaping the light synthesized by the same optical axis into uniform light; Wherein the G light source irradiates laser light, and the beam shaping lens includes a lens array in which a plurality of small lenses are arranged in a matrix form.
According to this configuration, it is possible to provide a projector that provides clear image quality by removing the speckle.

Description

Projector {Projector}

The present invention relates to a projector that provides clear picture quality by removing speckle.

Recently, due to the rapid development of the display field, consumers want to see brighter and clearer images on a larger screen. As a means for meeting the needs of such consumers, the development of display devices using laser light has been actively promoted.

1 is a block diagram of a conventional laser display system.

The use of a laser as a light source has the advantage that the color of an 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 laser projector using a laser as a light source uses a laser 11 as a light source instead of a lamp, and irradiates the display panel 13 with the laser light by the illumination optical system 12.

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

Such a conventional laser projector can increase the sharpness of the color and display an image close to natural colors by using a laser as a light source. In addition, the laser projector has a high contrast, so that a sharp image quality can be reproduced.

However, coherence, which is a characteristic of lasers, causes light to collect at a certain part of the screen, causing speckle to appear as small particles on the screen. The speckle phenomenon is a factor of degrading the image quality, which leads to a decrease in contrast and resolution.

In order to remove 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.

Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a projector that provides clear image quality by removing speckle.

According to an aspect of the present invention for achieving the above object, the projector includes a light source unit including an R light source for irradiating red light, a G light source for irradiating green light, and a B light source for irradiating blue light; A beam shaping lens for dividing the light emitted from the G light source and expanding the beam diameter; A focusing lens for focusing light emitted from the R light source and the B light source; A color combining unit for synthesizing the light emitted from the R light source, the G light source, and the B light source to the same optical axis; A mirror disposed at a rear end of the G light source to emit light emitted from the G light source to the beam shaping lens; A dichroic mirror disposed at a rear end of the focusing lens to reflect light emitted from the R light source and to transmit light emitted from the G light source; A fly's eye lens for uniformly synthesizing the light synthesized on the same axis from the color combining portion; A collimation lens for correcting the angle of light spread by the beam shaping lens positioned at the rear end of the G light source, the focusing lens positioned at the rear end of the R light source, and the B light source and incident in parallel to the fly's eye lens; And a condensing lens that focuses the light emitted from the fly's eye lens and emits the light to a display panel, wherein the G light source irradiates laser light, and the beam shaping lens includes a lens array in which small lenses are arranged in a matrix form. It is characterized by.

In addition, the lens array is characterized in that formed on one side or both sides of the beam shaping lens.

In addition, the small lens is characterized in that it has a circular or polygonal shape.

In addition, the diameter or the diagonal length of the small lens is characterized in that 50 to 100 ㎛.

In addition, the beam shaping lens is characterized in that the lens array is formed on the front and rear of the main body having a cylindrical or hexahedral shape.

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In addition, the thickness of the small lens is characterized in that 10 to 30 ㎛.

In addition, the lens array is characterized in that the center portion of the main body is disposed in a circular or rectangular form.

In addition, the lens array is disposed in the form of a square in the central portion of the main body, characterized in that the length of one side of the square is 1 to 2 mm.

In addition, the small lens has a convex portion protruding convexly from the surface, the thickness of the convex portion is characterized in that 1.5 to 4 ㎛.

In addition, the convex portion is characterized in that it has a radius of curvature of 0.1 to 0.4 mm.

In addition, the thickness of the main body is characterized in that 0.5 to 1 mm.

In addition, the color combining portion is characterized in that it comprises a dichroic mirror.

In addition, a collimation lens (colliamtion lens) disposed in front of the fly's eye lens; And further comprising:

In addition, the display panel disposed on the rear end of the fly's eye lens, and converts the light emitted from the light source to an image image; A condensing lens that focuses the light emitted from the fly's eye lens to the display panel; And further comprising:

According to another aspect of the present invention for achieving the above object, the projector includes a light source unit including an R light source for irradiating red laser light, a G light source for irradiating green laser light, and a B light source for irradiating blue laser light; A beam shaping lens disposed at the rear ends of the R light source, the G light source, and the B light source, for splitting the light emitted from the R light source, the G light source, and the B light source; A color combining unit for synthesizing the light emitted from the R light source, the G light source, and the B light source to the same optical axis; A fly's eye lens shaping the light synthesized by the same optical axis into uniform light; The beam shaping lens may include a lens array in which a plurality of small lenses are arranged in a matrix.

According to the present invention, it is possible to provide a projector that provides clear image quality by removing speckle.

1 is a block diagram of a conventional laser display system.
2 is a diagram showing a schematic configuration of a projector according to an embodiment of the present invention.
3 is a perspective view illustrating a beam shaping lens according to an embodiment of the present invention.
4 is a plan view showing a beam shaping lens according to the embodiment of the present invention.
5 is a side view illustrating the beam shaping lens according to the embodiment of the present invention.
6A is a diagram illustrating the shape of a beam incident on a fly's eye lens in the projector of the conventional embodiment.
FIG. 6B is a diagram illustrating the shape of a beam incident on a fly's eye lens in another conventional embodiment of the projector.
6C is a diagram illustrating the shape of a beam incident on a fly's eye lens in a projector according to an exemplary embodiment of the present invention.
7A is a diagram showing a path of light when the incident position of the laser light source is shifted in the conventional projector.
7B is a view showing a path of light when the incident position of the laser light source is shifted in the projector according to the embodiment of the present invention.
8 is a diagram showing a schematic configuration of a projector according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements throughout. The same reference numerals in the drawings denote like elements throughout the drawings.

2 is a diagram showing a schematic configuration of a projector according to an embodiment of the present invention. 3 is a perspective view illustrating a beam shaping lens according to an embodiment of the present invention.

The projector 100 includes a light source unit 110, a beam shaping lens 120, a focusing lens 122 and 124, a color combining unit 132, 134, 136, and 138, a collimation lens 140, and a fly's eye lens ( 150, a condensing lens 160, a display panel 170, and a projection optical system 180.

The light source unit 110 may include a G light source 112, an R light source 114, and a B light source 116. The G light source 112 irradiates green light, the R light source 114 irradiates red light, and the B light source 116 irradiates blue light.

The G light source 112 is composed of a laser light source for irradiating laser light. The laser light source may be configured using a diode pumping solid state laser (DPSS) or a laser diode (LD).

The R light source 114 and the B light source 116 may be configured as a laser light source or an LED light source. The LED light source may be configured using a light emitting diode (LED).

In general, as the beam diameter of light incident on the fly's eye lens 150 increases, the speckle is reduced and the uniformity of the light is improved. Speckle is a phenomenon in which light gathers at a certain part of the screen due to coherence, which is a characteristic of a laser, and generates shiny spots on the screen. This speckle phenomenon is a factor of degrading the image quality.

In general, the green light emitted from the G light source 112 has a smaller beam diameter than the blue or red light emitted from another light source. When the beam diameter of the light is small, there is a problem that the speckle is generated and the uniformity of the light is lowered. Therefore, it is preferable to enlarge the beam diameter of the light emitted from the G light source 112 and to enter the fly-eye lens 150.

However, if only the beam diameter is increased by using a general lens, a deviation occurs in the amount of light in the center and the outside of the beam shape, which causes a limitation in improving the final projection uniformity. In order to obtain the required beam diameter, a lens of high power (refractive index or curvature) is used or the distance is increased, which increases the manufacturing cost of the lens and increases the size of the projection system.

To this end, in the present embodiment, the light emitted from the G light source 112 is split while passing through the beam shaping lens 120 and is incident on the fly's eye lens 150 with the beam diameter enlarged. Since the green light occupies the largest portion of the white light, the expansion of the beam diameter to the green light is more effective than other blue or red light. The beam shaping lens 120 includes a lens array in which a plurality of small lenses are arranged in a matrix.

3 illustrates an example of the beam shaping lens 120. The beam shaping lens 120 may have a shape in which a lens array 122 in which a plurality of small lenses are arranged in a matrix shape is formed on a cylindrical or hexahedral body 121. The lens array 122 may be attached to one side or both sides of the body 121.

The light passing through the beam shaping lens 120 may have an improved uniformity as the beam diameter increases, and may be incident to the fly's eye lens 150.

The beam shaping lens 120 may be manufactured using plastic injection, molding of a glass lens, etching of a silicon wafer, or the like.

Focusing lenses 122 and 124 may be disposed at rear ends of the R light source 114 and the B light source 116, respectively. The focusing lens 122 collects light emitted from the R light source 114, and the focusing lens 124 collects light emitted from the B light source 116.

The color combining units 132, 134, 136, and 138 combine the light emitted from the G light source 112, the R light source 114, and the B light source 116 into the same optical axis. To this end, the color combining portions 132, 134, 136, and 138 include two mirrors 132 and 138 and two dichroic mirrors 134 and 136. The dichroic mirrors 134 and 136 reflect light in a specific wavelength region and transmit light in the remaining wavelength region. The light source unit 110 and the color combining units 132, 134, 136, and 138 may be configured in various forms in addition to those illustrated.

The mirror 132 is disposed at the rear end of the G light source 112 and serves to emit light emitted from the G light source 112 to the beam shaping lens 120. The beam shaping lens 120 may be positioned between the G light source 112 and the mirror 132.

The dichroic mirror 134 is disposed at the rear end of the focusing lens 122 to reflect light emitted from the R light source 114 and transmit light emitted from the G light source 112.

The dichroic mirror 136 is disposed at the rear end of the focusing lens 124 to reflect the light emitted from the G light source 112 and the R light source 114 and to transmit the light emitted from the B light source 116. .

The mirror 138 reflects the light emitted from the G light source 112, the R light source 114, and the B light source 116 and synthesized on the same optical axis toward the collimation lens 140.

The collimation lens 140 is spread by the beam shaping lens 120 located at the rear end of the G light source 112 and the focusing lenses 122 and 124 located at the rear end of the R light source 114 and the B light source 116. The angle of the light is corrected to be incident in parallel to the fly's eye lens 150. The collimation lens 140 may be omitted.

The fly's eye lens 150 serves to make the light synthesized with the same optical axis into uniform light.

The fly's eye lens 150 may have a form in which a plurality of small lenses are arranged. In this case, the size of the small lens may be between 50㎛ 2mm. If the size of the small lens is too small, a lattice pattern due to the coherence of the laser light appears on the screen 190. If the size of the small lens is too large, uniform light cannot be obtained and a clean image image cannot be formed.

The condensing lens 160 serves to focus the light emitted from the fly's eye lens 150 to the display panel 170. The condensing lens 160 may be configured in plural.

Light passing through the condensing lens 160 is incident to the display panel 170. The display panel 160 selectively transmits or blocks incident light, or changes an optical path to form an image image.

Representative examples of the display panel 170 include a digital micromirror device (DMD) panel, an LCD panel, and an LCoS panel.

The DMD panel is a driving method using a field sequential, and is used in a digital light processing (DLP) projector using a digital mirror arranged in a matrix form by the number of pixels. The DLP is a projector that realizes an image by reflecting light emitted from a light source to a screen by adjusting a light path by a digital mirror.

An LCD panel (Liquid Crystal Display Device) forms an image by selectively turning on or off the liquid crystal. Projectors using LCD panels include direct view, projection and reflection. The direct view projector is a method in which light from the backlight behind the LCD panel directly observes the generated image as it passes through the LCD panel. Projection type projectors use an projection lens to magnify an image generated while passing through an LCD panel, and then project the image onto a screen to observe an image reflected from the screen. The reflective type has the same structure as the projection type, but forms a reflective film on the lower substrate to enlarge and project the reflected light onto the screen.

Liquid crystal on silicon (LCoS) panel is a type of reflective liquid crystal display, and is an optical device that operates a reflective substrate using a silicon substrate instead of transparent glass among double-sided substrates of a conventional LCD panel.

Light passing through the display panel 170 is incident to the projection optical system 180. The projection optical system 180 serves to project a light beam forming an image onto the screen 190 and includes a plurality of lenses arranged in a line. The type, number and arrangement of lenses employed in the projection optical system 180 may be freely selected by those skilled in the art.

4 is a plan view showing a beam shaping lens according to the embodiment of the present invention. 5 is a side view illustrating the beam shaping lens according to the embodiment of the present invention.

4 and 5, the beam shaping lens 120 includes a lens array 122 in which a plurality of small lenses 123 are arranged on a cylindrical body 121.

The diameter of the main body 121 may be 2.5 to 5 mm, preferably 3 mm. The lens array 122 may be disposed on the main body 121 in a circular or polygonal shape, preferably a square shape. In FIG. 4, the length of one side of the lens array 122 disposed in a square shape may be 1 to 2 mm, and preferably 1.25 mm.

In the lens array 122, a plurality of small lenses 123 are arranged in a matrix form. Each of the small lenses 123 may be formed of a polygon such as a circular, rectangular convex lens shape, or hexagonal convex lens shape. The diameter or the diagonal length of the small lens 123 may be 50 to 100 μm. Here, the diagonal length means the length of the longest diagonal line among the diagonal lines that may appear in the small lens 123.

In the present embodiment, a small lens 123 having a square shape is shown. The length a of one side of the square may be 40 to 60 μm, and preferably 50 μm.

The lens array 122 is formed on one side or both sides of the body 121, preferably on both sides. In this embodiment, the lens array 122 is formed on both surfaces of the main body 121. The thickness b of the body 121 may be 0.6 to 1.0 mm, and preferably 0.8 mm.

The thickness c of the lens array 122 (or the small lens) may be 10 to 30 μm, and preferably 20 μm.

The plurality of small lenses 123 having convex images are arranged in the lens array 122. The thickness d of the convex portion projecting convexly from the surface of the small lens 123 may be 1.5 to 4 μm, preferably 2.3 μm. In addition, the radius of curvature R of the convex portion may be 0.1 to 0.4 mm, preferably 0.26 mm.

6A is a diagram illustrating the shape of a beam incident on a fly's eye lens in the projector of the conventional embodiment. FIG. 6B is a diagram illustrating the shape of a beam incident on a fly's eye lens in another conventional embodiment of the projector. 6C is a diagram illustrating the shape of a beam incident on a fly's eye lens in a projector according to an exemplary embodiment of the present invention.

Referring to FIG. 6A, light emitted from the laser light source 20 is incident to the collimation lens 22 via the mirror 21. Light emitted from the collimation lens 22 is incident to the fly's eye lens 23.

In general, as the beam diameter of the light incident on the fly's eye lens 23 increases, the uniformity of the final projected image increases, which helps to reduce the speckle.

In the figure, the right side shows the shape of the light incident on the fly's eye lens 23, and it can be seen that the light has a small beam diameter and a low uniformity.

FIG. 6B shows a configuration in which a beam diameter is extended by arranging the focusing lens 32 at the rear end of the laser light source 30. As the focusing lens 32, a concave lens or a convex lens may be used. The concave lens is easy to extend the beam diameter, but there is a disadvantage that the path of the light changes abruptly even if the incident direction of the light is slightly distorted. Therefore, in general, the focusing lens 32 is formed by using a convex lens that is easy to adjust the path of light despite the deterioration of the beam diameter extension performance.

Light emitted from the laser light source 30 is reflected by the mirror 31 and is incident on the focusing lens 32. Light whose beam diameter is extended by the focusing lens 32 is incident on the collimation lens 34 via the mirror 33. Light emitted from the collimation lens 34 is incident to the fly's eye lens 35.

In the figure, the right side shows the shape of light incident on the fly's eye lens 35. As shown, it can be seen that the beam diameter is expanded in comparison with the conventional embodiment shown in Fig. 6A, but the uniformity of the center and the outside of the beam is not good.

Referring to FIG. 6C, the beam shaping lens 120 is positioned at the rear end of the laser light source 112 in the projector according to the embodiment of the present invention. The light emitted from the laser light source 112 is reflected by the mirror 132 and splits while passing through the beam shaping lens 120 to expand the beam diameter. Light whose beam diameter is extended by the beam shaping lens 120 is incident to the collimation lens 140 via the mirror 138. The light emitted from the collimation lens 140 is incident to the fly's eye lens 150.

In the figure, the right side shows the shape of light incident on the fly's eye lens 150. As shown, it can be seen that the uniformity of the center and the outside of the beam is also improved as the beam diameter is further extended as compared with the conventional embodiments shown in FIGS. 6A and 6B.

7A is a diagram showing a path of light when the incident position of the laser light source is shifted in the conventional projector. 7B is a view showing a path of light when the incident position of the laser light source is shifted in the projector according to the embodiment of the present invention.

Referring to FIG. 7A, when the position of the light emitted from the laser light source 30 is shifted to the left of 0.5 mm, the light is reflected by the mirror 31 and is incident on the upper end of the focusing lens 32. The light emitted from the focusing lens 32 is refracted so that it does not enter the fly's eye lens 35.

Referring to FIG. 7B, when the position of the light emitted from the laser light source 112 is shifted to the left of 0.5 mm, the light is reflected by the mirror 132 and is incident on the upper end of the beam shaping lens 120. Since the beam shaping lens 120 is formed by decreasing the size of each unit lens, the beam shaping lens 120 may be incident to the fly's eye lens 150 without a large change in the path of the light even when the incident position of the light is shifted.

As described above, the projector according to the embodiment of the present invention includes a beam shaping lens 120 for dividing the light emitted from the G light source 112 to enlarge the beam diameter. The beam shaping lens 120 includes a lens array in which a plurality of small lenses are arranged in a matrix. The green light having the enlarged beam diameter is combined with the blue and red light and incident to the fly's eye lens 150. This enlargement of the beam diameter prevents speckle and improves the uniformity of the light.

In addition, since the beam shaping lens 120 of the projector is formed of a plurality of small lenses having a smaller size of the unit lens, the beam shaping lens 120 is not sensitive to assembly tolerances, thereby improving assembly performance.

8 is a diagram showing a schematic configuration of a projector according to another embodiment of the present invention. The same parts as in the embodiment shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

The projector 200 includes a light source unit 210, a beam shaping lens 220, a color combining unit 132, 134, 136, and 138, a collimation lens 140, a fly's eye lens 150, and a condensing lens 160. , A display panel 170, and a projection optical system 180.

The light source unit 210 may include a G light source 212, an R light source 214, and a B light source 216. The G light source 212 irradiates green light, the R light source 214 irradiates red light, and the B light source 216 irradiates blue light.

The G light source 212, the R light source 214, and the B light source 216 are all composed of a laser light source for irradiating laser light.

A beam shaping lens 220 is disposed at the rear ends of the G light source 212, the R light source 214, and the B light source 216, respectively. The configuration of the beam shaping lens 220 is the same as that of the beam shaping lens 120 illustrated in FIGS. 2 to 5.

Therefore, the laser light emitted from the G light source 212, the R light source 214, and the B light source 216 is incident on the fly's eye lens 150 by the beam shaping lens 220 with the beam diameter enlarged.

Compared with the embodiment of FIG. 2, the present embodiment differs in that the beam shaping lens 220 is disposed at the rear ends of the R light source 214 and the B light source 216. Although the beam shaping lens 220 is intended to prevent speckle and to improve the uniformity of light by expanding the beam diameter, the beam shaping lens 220 may be provided only at the rear end of either the R light source 214 or the B light source 216 as necessary. ) May be arranged.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention will be.

100: Projector
110: light source
112: G light source
114: R light source
116: B light source
120: beam shaping lens
121: main body
122: lens array
122, 124: focusing lens
132, 134, 136, 138: color synthesis part
140: collimation lens
150: Fly Eye Lens
160: condensing lens
170: display panel
180: projection optical system
190: screen

Claims (16)

A light source unit including an R light source for irradiating red light, a G light source for irradiating green light, and a B light source for irradiating blue light;
A beam shaping lens for dividing the light emitted from the G light source and expanding the beam diameter;
A focusing lens for focusing light emitted from the R light source and the B light source;
A color combining unit for synthesizing the light emitted from the R light source, the G light source, and the B light source to the same optical axis;
A mirror disposed at a rear end of the G light source to emit light emitted from the G light source to the beam shaping lens;
A dichroic mirror disposed at a rear end of the focusing lens to reflect light emitted from the R light source and to transmit light emitted from the G light source;
A fly's eye lens for uniformly synthesizing the light synthesized on the same axis from the color synthesizing unit;
A collimation lens for correcting the angle of light spread by the beam shaping lens positioned at the rear end of the G light source, the focusing lens positioned at the rear end of the R light source, and the B light source and incident in parallel to the fly's eye lens;
A condensing lens configured to focus light emitted from the fly's eye lens and output the light to a display panel;
The G light source is irradiated with laser light,
And the beam shaping lens comprises a lens array in which small lenses are arranged in a matrix. The method of claim 1,
And the lens array is formed on one or both sides of the beam shaping lens. 3. The method of claim 2,
And the small lens has a circular or polygonal shape. The method of claim 3,
The projector has a diameter or a diagonal length of the small lens is 50 to 100 ㎛. 3. The method of claim 2,
The beam shaping lens is characterized in that the lens array is formed on the front and rear of the main body having a cylindrical or hexahedral shape. delete The method of claim 5,
The small lens has a thickness of 10 to 30 ㎛ projector. The method of claim 5,
The lens array is characterized in that the projector is arranged in a circular or rectangular shape in the center of the body. 9. The method of claim 8,
The lens array is disposed in the form of a square in the center of the main body, the length of one side of the square, characterized in that the projector is 1 to 2 mm. The method of claim 1,
And the small lens has a convex portion projecting convexly from the surface, wherein the thickness of the convex portion is 1.5 to 4 [mu] m. The method of claim 10,
And the convex portion has a radius of curvature of 0.1 to 0.4 mm. The method of claim 5,
And the thickness of the main body is 0.5 to 1 mm. delete delete The method of claim 1,
A display panel disposed at a rear end of the fly's eye lens and converting light emitted from the light source into an image image;
Projector characterized in that it further comprises. delete

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