KR20100129626A - Image projection apparatus - Google Patents

Abstract

The present invention includes a light source unit consisting of a plurality of light sources, a photosynthesis unit for synthesizing the lights so that the light generated from the light sources proceed in the same optical path, and a display panel unit for forming an image using the synthesized light. And the photosynthesis unit disposed between the light sources and separating at least one of the lights into first and second polarizations having different polarization directions, and advancing the first and second polarizations in directions crossing each other. Polarization conversion modules disposed between the separation element and the light source and the polarization separation element, respectively, to reflect the polarizations toward the polarization separation element and convert one of the first and second polarizations into another one; And reflecting any one of the lights toward the optical path and covering one surface of the polarization splitting element. It provides an image projection apparatus comprising a reflection unit disposed.

Description

Image Projection Device {IMAGE PROJECTION APPARATUS}

The present invention relates to an image projection apparatus for synthesizing light generated from a plurality of light sources and realizing an image using the synthesized light.

As the information age evolves rapidly, the importance of display devices for implementing large screens is being emphasized. An example of a device for implementing such a large screen is an image projection apparatus having a function of magnifying and projecting an image.

An image projection device refers to a device that implements an image by using light generated from a light source and projects the implemented image, and examples thereof include a projector and a projection television.

Recently, as the portable function of the image projection apparatus is important, various new attempts have been applied in terms of hardware or software. As one of these attempts, there is an effort to further reduce the image projection value, but when the image projection apparatus is downsized, there is a problem that the optical performance of the image projection apparatus is reduced. Therefore, a method of minimizing the image projection value and improving optical performance may be considered.

An object of the present invention is to provide an image projection for implementing the image in a different method than the prior art.

Another object of the present invention is to provide an image projection value which is more compact and excellent in optical performance.

An image projection apparatus related to an embodiment of the present invention for realizing the above object includes a light source unit, a photosynthesis unit, and a display panel unit. The light source unit is composed of a plurality of light sources. The photosynthesis unit synthesizes the lights such that the light generated from the light sources travels in the same light path. The display panel unit forms an image using the synthesized light. The photosynthesis unit includes a polarization splitting element, polarization change modules, and a reflection unit. The polarization splitting element is disposed between the light sources, separates at least one of the lights into first and second polarizations having different polarization directions, and advances the first and second polarizations in directions crossing each other. Polarization conversion modules are respectively disposed between the light sources and the polarization splitting element to reflect the polarizations toward the polarization splitting element, and convert one of the first and second polarizations into another. The reflection unit is formed to reflect one of the lights toward the light path and is disposed to cover one surface of the polarization splitter. The polarization splitting device may be a polymerizing beam splitter (PBS) film.

According to an aspect of the present invention, the photosynthetic part includes a plurality of rectangular prisms arranged so that the surfaces forming the hypotenuse face each other. The polarization splitting element is disposed between the surfaces forming the hypotenuse. The reflection unit may include a dichroic mirror. The dichroic mirror is coated on the surface forming the hypotenuse of any of the rectangular prisms, and is formed to reflect light corresponding to any one of the three primary colors and transmit the rest. The reflection unit may include a reflection filter. The reflective filter is disposed between the plane forming the hypotenuse of any of the rectangular prisms and one surface of the polarization splitting element, and reflects the light corresponding to any one of the three primary colors and transmits the other. The reflection unit is formed to reflect the blue light, and may be disposed between the light source of the blue light and the polarization splitter.

According to another aspect of the present invention, the polarization conversion modules each include a polarization conversion element and a dichroic filter. The polarization converting device has an emission surface for converting the incident linear flat light into circular flat light and outputs the light, and the incident surface is disposed to face the polarization splitting device. The dichroic filter transmits light corresponding to any one of the three primary colors, reflects the rest, and is disposed to cover the emission surface.

According to another aspect of the present invention, the image projecting device may include collimator lenses disposed between the light source unit and the photosynthesis unit so that light generated from the light sources travels in a predetermined direction.

The image projecting device according to the present invention configured as described above may combine some of the lights generated from the plurality of light sources and reflect the others, thereby polarizing the lights with higher brightness. In addition, the optical performance can be improved through this.

In addition, the present invention can form a shorter optical path through the polarization splitting element, the polarization conversion module and the reflection unit. Through this, a small image projection apparatus can be implemented.

EMBODIMENT OF THE INVENTION Hereinafter, the image projection apparatus which concerns on this invention is demonstrated in detail with reference to drawings. In the present specification, the same or similar reference numerals are assigned to the same or similar configurations in different embodiments, and the description thereof is replaced with the first description. As used herein, the singular forms "a", "an" and "the" include plural forms unless the context clearly indicates otherwise.

The image projection apparatus described herein includes not only a projector and a projection TV, but also a mobile termianl, a laptop computer, a personal digital assistant (PDA), and a portable multimedia player (PMP). It may include a very small projection device that can be mounted, such as navigation. Hereinafter, the image projection unit related to the present invention will be described based on the projector.

1 is a perspective view of the image projection apparatus 100 according to the present invention viewed from the front.

Since the components shown in FIG. 1 are not essential, the image projection apparatus 100 may have more components or fewer components.

The external appearance of the image projection apparatus 100 is formed by the upper and lower cases 111 and 112. Various optical parts and electronic parts are embedded in the space formed by the upper and lower cases 111 and 112. At least one intermediate case may be further disposed between the upper and lower cases 111 and 112.

The operation unit 113 may be disposed on the upper case 111. The operation unit 113 may be employed in any manner as long as the user is tactile manner to operate while having a tactile feeling.

The operation unit 113 receives a command for controlling the operation of the image projection apparatus 100. In functional terms, the operation unit 113 may be used to input menus such as start, end, and the like.

In addition, the operation unit 113 may be manipulated to zoom in or zoom out an image projected by the image projection apparatus 100. The operation unit 113 may be operated to focus the image projected by the image projection apparatus 100.

The lower case 112 may include a projection lens unit 114, a first air flow unit 115a, and the like.

The projection lens unit 114 is formed to enlarge an image projected by the image projection apparatus 100. The projection lens unit 114 may be formed of, for example, a lens group in which respective magnification projection lenses are arranged at predetermined intervals. The projection lens unit 114 may be formed such that the distance between the enlarged projection lenses is adjusted by the manipulation unit 113. Through this, the zoom or focusing function of the image projection apparatus 100 may be implemented.

The first air flow unit 115a is formed of a plurality of through holes to allow air to flow into the image projection apparatus 100. Through this, cooling of the image projection apparatus 100 using forced convection is possible.

2 is a perspective view of the image projection apparatus 100 of FIG.

The lower case 112 may include a second air flow unit 115b, an interface 116, a power supply unit 117, and the like.

The second air flow unit 115b is formed of a plurality of through holes like the first air flow unit 116a (see FIG. 1) to allow air to flow into the image projection apparatus 100.

The interface 116 may be a path through which the image projection apparatus 100 may exchange data with an external device. Image data corresponding to an image to be projected by the image projection apparatus 100 through the interface 116 may be input from the outside. Referring to this figure, the interface 116 includes a connection terminal that can be electrically connected to an electronic device capable of supplying video or audio data, for example, a computer, a DVD player, or the like.

The power supply unit 117 is mounted on the lower case 112 for supplying power to the image projection apparatus 100. The power supply unit 117 may be configured to receive, for example, AC power to be converted into DC power. However, the configuration of the power supply unit 117 is not limited to this, and may be detachably coupled for charging as a rechargeable battery.

One of the upper and lower cases 111 and 112 may include a sound output unit in the form of a speaker, and an antenna for receiving a broadcast signal may be additionally disposed.

3 is an exploded view of the image projection apparatus 100 of FIG.

The control circuit board 121 may be mounted on the lower case 112. The control circuit board 121 may be configured as an example of a control unit for operating various functions of the image projection apparatus 100.

The lower case 112 may be equipped with an optical system 130. The optical system 130 refers to a system of optical components in which an image reflector or lens is properly arranged to realize an image of an object by using reflection or refraction of light in the image projection apparatus 100. A structure (not shown) on which the optical system 130 may be assembled may be further disposed between the optical system 130 and the lower case 112.

The optical system 130 may include at least one of the light source unit 140, the photosynthesis unit 160, the illumination optical unit 170, and the display panel unit 180.

The light source unit 140 includes a plurality of light sources 141, 142, and 143. The light sources 141, 142, and 143 may be, for example, light emitting diodes (LEDs), laser diodes (LDs), or the like. The light sources 141, 142, and 143 generate light corresponding to any one of three primary colors. For example, the light sources 141, 142, and 143 may be red, green, and blue light emitting diodes that emit light of red, green, and blue, respectively. In the drawings and the following description, the light sources 141, 142, and 143 are based on one each, but the present invention is not limited thereto. For example, the light sources 141, 142, and 143 may be red, green, and blue light emitting diode arrays arranged in plural such that the red, green, and blue light emitting diodes each have a common light emitting surface.

Referring to the drawings, the light sources 141, 142, and 143 face light sources 141 and 143 of red and blue light, and the light source 142 of green light includes light sources 141 and 143 of red and blue light. It is arranged to look in between.

The photosynthesis unit 160 is formed between the light sources 141, 142, and 143. The photosynthesis unit 160 synthesizes the lights such that the light generated from the light sources 141, 142, and 143 travels in the same light path. Various colors may be realized by the combination of the synthesized lights.

Collimator lenses 191, 192, and 193 may be disposed between the light source unit 140 and the photosynthesis unit 160. The collimator lenses 191, 192, and 193 are disposed adjacent to the light sources 141, 142, and 143 to advance light generated from the light sources 141, 142, and 143 in a predetermined direction.

The synthesized light passes through the illumination optical unit 170 and is illuminated by the display panel unit 180 that implements the image. The illumination optical unit 170 is formed of a fly's eye lens (FEL) 171, illumination lenses 172, a mirror 173, and the like to illuminate light on the display panel unit 180.

The display panel unit 180 forms an image using the synthesized light. The display panel unit 180 implements an image by reflecting the composite light illuminated on the incident surface, and may be a digitally controlled reflective electronic device. The image implemented in the display panel unit 180 is enlarged and projected through the projection lens unit 114.

The electronic device may be, for example, a digital micromirror device (DMD) in which a micromirror in which the inclination angle is changed to an ON state and an OFF state is arranged in a lattice on a plane. In addition, the electronic device may be a liquid crystal on silicon (LCOS) panel capable of realizing an image by reflecting synthetic light among liquid crystal display devices.

Hereinafter, the photosynthesis unit 160 will be described in more detail with reference to FIGS. 4 to 5C. 4 is an exploded view of the photosynthesis unit 160 of FIG. 3, and FIGS. 5A to 5C are conceptual views illustrating paths of light corresponding to three primary colors, respectively.

Referring to FIG. 4, the photosynthesis unit 160 includes a polarization splitter 161, polarization conversion modules 162a, 162b, and 162c, and a reflection unit 163.

The polarization splitting element 161 is disposed between the light sources 141, 142, 143 and FIG. 3, and separates at least one of the lights into first and second polarizations having different polarization directions. The second polarized light is advanced in the direction crossing each other.

The polarization splitting element 161 is formed to transmit one of the first and second polarizations and reflect the other. The first and second polarizations may be, for example, P waves and S waves which are linearly polarized light, respectively.

The photosynthetic unit 160 may include a plurality of rectangular prisms 164a and 164b. Right angle prisms 164a and 164b refer to a prism of a triangular prism shape having a right angle. The rectangular prisms 164a and 164b are arranged such that the surfaces forming the hypotenuse face each other. At least one surface of the rectangular prisms 164a and 164b is orthogonal to the optical axes of the light sources 141, 142 and 143, and the plane forming the hypotenuse may be inclined with respect to the optical axis.

Referring to this figure, rectangular prisms 164a and 164b may be mounted on both surfaces of the polarization splitting element 161, respectively. Right angle prisms 164a and 164b fix the polarization splitting element 161. As the polarization splitting element 161 is inclined with respect to the light generating surface of the light sources 141, 142, 143, when the light generated from the light sources 141, 142, 143 reaches the polarization splitting element 161. Path difference occurs until. The rectangular prisms 164a and 164b alleviate or prevent distortion of the image due to the optical path difference.

The polarization splitting element 161 is disposed between the surfaces forming the hypotenuse of the rectangular prisms 164a and 164b. The polarization splitter 161 may be a polymerizing beam splitter (PBS) film.

The polarization conversion modules 162a, 162b, and 162c are disposed between the light sources 141, 142, and 143 and the polarization splitting element 161, respectively. The polarization conversion modules 162a, 162b, and 162c are formed to reflect polarizations emitted from the polarization separation element 161 toward the polarization separation element 161 and convert one of the first and second polarizations into another. .

The polarization conversion modules 162a, 162b, and 162c may include a polarization conversion element 165 and a dichroic filter 166, respectively.

The polarization converting element 165 has an emission surface for converting the incident linear flat light into circular flat light and outputs the light, and the incident surface is disposed to face the polarization converting element 165. The polarization conversion element 165 may be, for example, a quarter wave plate (QWP). The first and second polarized light which are linearly polarized light are converted into circular light while passing through the polarization conversion element 165.

The dichroic filter 166 transmits light corresponding to any one of the three primary colors, and reflects the rest of the dichroic filter 166, and is disposed to cover the emission surface of the polarization conversion element 165.

The polarization conversion modules 162a, 162b, and 162c configured as described above convert any one of the first and second polarization into the other by the following principle. For example, if the first polarized light is P pie, the P wave is converted into the first circularly polarized light while passing through the polarization converting element 165, and the polarization direction is changed as reflected by the dichroic filter 166 to change the second circularly polarized light. Becomes The second circularly polarized light is converted into the S wave while passing through the polarization converting element 165 again.

Referring to this figure, the reflection unit 163 is formed to reflect one of the light generated from the light sources 141, 142, 143 toward the light path through which the light synthesized in the photosynthesis unit 160 travels. The reflection unit 163 is disposed to cover one surface of the polarization splitting element 161.

The reflection unit 163 may be a dichroic mirror. The dichroic mirror is coated on the hypotenuse of one of the rectangular prisms 164a and 164b and reflects the light corresponding to any one of the three primary colors, and transmits the other. The reflection unit 163 is configured to reflect the blue light, and is disposed between the light source 143 and the polarization splitting element 161 of the blue light.

As described above, the photosynthesis unit 160 formed through the polarization splitting element 161, the polarization conversion modules 162a, 162b, and 162c and the reflection unit 163 may form a shorter optical path. Through this, the image projection apparatus can be further miniaturized.

Hereinafter, referring to FIGS. 5A to 5C, the advancing paths of the green, red, and blue light formed by the photosynthesis unit 160 configured as described above will be described in detail.

Referring to the drawings, the dichroic filter 166 is composed of red, green, and blue dichroic filters 166a, 166b, and 166c that transmit red, green, and blue light, respectively. The dichroic filters 166a, 166b, and 166c are arranged to face the light sources 141, 142, 143 (see FIG. 3) of red, green and blue light, respectively.

Referring to FIG. 5A, the green light generated by the light source 142 of the green light passes through the green dichroic filter 166b and enters the polarization splitter 161. The green light is separated into P and S waves of red light by the polarization splitting element 161. The P wave travels through the polarization splitter 161 toward the optical path of the synthesized light, and the S wave is reflected by the polarization splitter 161 and travels toward the red light source 141. S-waves are converted into circularly polarized light while passing through the polarization conversion element 165 and reflected by the red dichroic filter 166a. The circularly polarized light whose phase is inverted by the reflection is converted into P waves while passing through the polarization conversion element 165 again. The converted P wave passes through the polarization splitting element and is converted into S wave again by the polarization conversion module 162c adjacent to the light source 143 of blue light. The converted S-waves are reflected by the polarization splitting device and travel toward the optical path of the synthesized light.

Referring to FIG. 5B, the red light generated by the red light source 141 passes through the green dichroic filter 166a and enters the polarization splitter 161. The S-wave of red light travels toward the optical path of the light reflected and synthesized by the polarization splitting element 161. The P-wave of red light is converted into S-wave in the polarization conversion module 162c adjacent to the light source 143 of blue light, and is converted back to P-wave in the polarization conversion module 162b adjacent to the light source 142 of green light. 161 passes through and proceeds toward the optical path of the synthesized light.

Referring to FIG. 5C, blue light generated by the light source 143 of blue light passes through the blue dichroic filter 166c and proceeds toward the polarization splitter 161. The blue light travels toward the optical path of the light reflected and synthesized by the reflection unit 163 before reaching the polarization splitting element 161.

The polymer material forming the polarization splitting element 161 generally has a property of absorbing blue light. Since blue light is not incident on the polarization splitting element 161 by the reflection unit 163, the light may be synthesized at a higher brightness.

6A to 6C are simulation results showing optical performances when the light is synthesized using the X plate, when there is no reflection unit, and when the photosynthesis unit 160 of FIG. 4 is used.

Referring to FIG. 6A, when the light is synthesized using the X plate, the light efficiency is 65.6 percent (%). Referring to FIG. 6B, the light efficiency is 73.2 percent when there is no reflection unit 163 in the photosynthesis unit 160. 6C, the light efficiency is 69.4 percent in the case where there is the reflection unit 163 (see FIG. 4 above) in the photosynthesis unit 160.

Referring to the simulation result, the synthesis unit 160 has improved light efficiency than when the light is synthesized using the X plate. However, the photosynthesis 160 has a slightly reduced light efficiency than the reflection unit 163 is absent. However, the light efficiency decrease by the reflection unit 163 is insignificant, and since the blue light is not absorbed by the polarization splitting device, the photosynthesis unit 160 increases the reliability of the synthesis of red, green, and blue light. This improves optical performance, such as more accurate colors in the projected image.

7 is a conceptual diagram illustrating another embodiment of an image projection apparatus according to the present invention.

Referring to this figure, an integrator unit 271 may be disposed on the light exit surface of the photosynthesis unit 260 in the image projection apparatus 200. The integrator unit 271 has an incident surface and an exit surface, and is formed to totally reflect the light to go out between the entrance surface and the exit surface to the inside. The integrator unit 271 may be, for example, a light tunnel, a rod lens, or the like. The integrator unit 271 becomes an integrator of the light in the image projection apparatus 200, forms the shape of the illumination, and ensures the uniformity of the illumination.

Referring to this figure, the reflection unit 263 is formed of a reflection filter. The reflection filter is disposed between the hypotenuse of one of the right angle prisms 264a and 264b and one surface of the polarization splitting element 261, and reflects the light corresponding to any one of the three primary colors and transmits the rest. . The reflection filter is formed to reflect blue light, and is disposed between the light source 243 of the blue light and the polarization splitting element 261. As the reflection unit 263 is formed of a reflection filter, the manufacturing of the photosynthesis unit 260 may be simpler.

8 is a perspective view illustrating a portable terminal 300 to which the image projection apparatuses 100 and 200 of the present invention are applied.

Referring to the drawing, the portable terminal 300 is formed of a first portion 310 having a display 311 and another second portion 320.

The display 311 is formed to display image information through a window. The display 311 may occupy most of the first portion 310.

The second part 320 is provided with an image projection apparatus 100, 200, FIGS. 3 and 7 for projecting image information to the outside. Only the optical system 130 (refer to FIG. 3) may be built in the portable terminal 300. The optical system 130 is built in the terminal, and the projection lens unit 114 (see FIG. 1) is exposed to the outside to enlarge and project the image information. The projected image information may be enlarged and displayed on an external screen.

The second part 320 is provided with a projection operation unit 321 for operation related to the operation of the image projection apparatus (100, 200). Operations related to the operation of the image projection apparatus 100, 200 may be, for example, start of operation, end of operation, focusing of image information, zooming, and the like. .

The image projection value is not limited to the configuration and method of the above-described embodiments, but the embodiments may be configured by selectively combining all or some of the embodiments so that various modifications can be made.

1 is a perspective view of the image projection device according to the present invention from the front.

Figure 2 is a perspective view of the image projection of Figure 1 from the back.

3 is an exploded view of the image projection apparatus of FIG.

4 is an exploded view of the photosynthesis unit of FIG. 3;

5A to 5C are conceptual views illustrating paths of light corresponding to three primary colors, respectively.

6A to 6C are simulation results showing optical performances when the light is synthesized using the X plate, when there is no reflection unit, and when the photosynthesis unit of FIG. 4 is used.

7 is a conceptual diagram showing another embodiment of the image projection apparatus according to the present invention.

8 is a perspective view showing a portable terminal to which the image projection apparatus of the present invention is applied.

Claims (8)

A light source unit comprising a plurality of light sources; A photosynthesis unit for synthesizing the lights such that the lights generated from the light sources travel in the same light path; And A display panel unit which forms an image using the synthesized light; The photosynthetic unit, A polarization splitting element disposed between the light sources, separating at least one of the lights into first and second polarizations having different polarization directions, and advancing the first and second polarizations in a direction crossing each other; Polarization conversion modules disposed between the light sources and the polarization splitting elements, respectively, to reflect the polarizations toward the polarization splitting element, and convert one of the first and second polarizations into another; And And a reflection unit which is formed to reflect one of the lights toward the light path and covers one surface of the polarization splitting device. The method of claim 1, The photosynthesis unit further includes a plurality of rectangular prisms arranged so that the surfaces forming the hypotenuse face each other, The polarization splitting device is an image projection apparatus characterized in that arranged between the sides forming the hypotenuse. The method of claim 2, The reflection unit is an image projection apparatus is coated on a surface forming any hypotenuse of the rectangular prism, and includes a dichroic mirror that reflects light corresponding to any one of the three primary colors and transmits the rest. The method of claim 2, The reflective unit is disposed between the surface forming any hypotenuse of the rectangular prism and one surface of the polarization splitting element, and includes a reflective filter that reflects light corresponding to any one of the three primary colors and transmits the rest Video projection device. The method according to claim 3 or 4, And the reflection unit is formed to reflect blue light, and is disposed between the light source of the blue light and the polarization splitting device. The method of claim 1, The polarization splitting device is an image projection apparatus, characterized in that the polymer material PBS (Polarizing Beam Splitter) film. The method of claim 1, The polarization conversion module, respectively A polarization conversion device having an emission surface for converting the incident linear flat light into circular flat light and outputting the incident flat surface, the incident surface facing the polarization splitting device; And And a dichroic filter configured to transmit light corresponding to any one of the three primary colors, reflect the remaining one, and cover the emission surface. The method of claim 1, And collimator lenses disposed between the light source unit and the photosynthetic unit such that light generated from the light sources travels in a predetermined direction.

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