KR100672411B1 - Lighting device and projection display device using the same - Google Patents

Abstract

The present invention is to provide a lighting device that does not increase the etendue even when using a plurality of light sources in the lighting device and a projection display device using the same, the light is uniform through the total reflection of the light incident into the interior In a lighting apparatus comprising a waveguide emitted to one side and a light source having at least one light source in contact with the outer surface of the waveguide to emit light into the waveguide, the light guide of the light exits the outer surface of the waveguide The effect of reducing the etendue of the entire apparatus is provided by making it smaller than the sum of the surface areas constituting the etendue of each of the entire light sources.

Etendue, optical system, projector, lighting source, lighting system

Description

Lighting apparatus and projection display device using the same

1A to 1C show a first embodiment showing the structure of a lighting device according to the present invention;

2A to 2D show a second embodiment showing the structure of a lighting device according to the present invention.

3a and 3b show a third embodiment showing the structure of a lighting device according to the invention;

4 is a fourth embodiment showing the structure of a lighting apparatus according to the present invention;

5a and 5b show a fifth embodiment showing the structure of a lighting apparatus according to the present invention;

6 is a first embodiment showing a projection display apparatus using a lighting apparatus according to the present invention;

7A and 7B are views showing the structure of an illumination system used in the projection display device according to the present invention.

8 is a first embodiment showing a projection display apparatus using a lighting apparatus according to the present invention;

9 is a second embodiment showing a projection display apparatus using a lighting apparatus according to the present invention.

10 is a third embodiment showing a projection display apparatus using a lighting apparatus according to the present invention.

* Explanation of symbols for main parts of the drawings

10: waveguide 20: light source

40: groove 50: refractive index layer

100, 200: lighting device 110: integrator

310: LCD panel 320: dichroic filter

330: color selection polarizer 340: projection lens system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display device, and more particularly, to a projection display device using a lighting device with minimal etendue.

In general, the optical system of a projection engine can be roughly divided into an illumination system and a projection system.

The illumination system serves to uniformly illuminate the light from the lamp to an imager of a small size through an integrator or a fly eye lens (FEL). In addition, the projection system receives illumination light into each panel through the illumination system, and enlarges the imager to form an image on the screen.

In this case, the most important performance in the illumination system of the projection engine is how efficiently the light from the light source is focused on the imager.

However, in the case where the light source is a point light source, in theory, all light emitted from the light source can be collected, but in fact, there is no point light source and all light sources have an area or volume, so that the light collection efficiency has a theoretical limit.

In particular, the light source used in the projection engine is an ultra-high-pressure discharge lamp is mainly used arc lamp (arc lamp), the arc lamp is used as a principle of emitting light to the discharge phenomenon occurring between the electrodes, the light generated is the It becomes a light source having a length equal to an arc gap between electrodes.

The light collection efficiency is generally higher the closer to the point light source, i.e., the smaller the arc gap, the higher the efficiency, which is very difficult to make small as it is related to the life of the lamp. Therefore, arc gaps made by the technology of lamp manufacturers in advanced countries are manufactured at about 1 mm for this reason.

Since the light source has a constant volume as described above, the theoretical condensing efficiency is limited by etendue.

The etendue is a value related to the area and solid angle, as shown in the equations Equation 1 and 2 below. A light source having a small etendue, that is, a light source close to a point light source, is small in a small area using a lens or a mirror. The light can be condensed to have a solid angle.

Etendue (E) =

In this case, dA denotes the unit area of the light source, dΩ denotes the unit solid angle of the light source, and θ denotes an angle formed between the normal direction of the light source and the center of the solid angle.

The etendue E in the plane is defined as in Equation 2 below.

Where A is the area and F / # represents the F number of the lens.

In the end, as defined in Equations 1 and 2, the projection engine is advantageous for smaller imagers and larger F / # s.

As described above, the illumination system should be illuminated at a large F / #, that is, at a small solid angle, in a small area. However, since the etendue of the light source is limited, the illumination system cannot condense at a small solid angle in a small area as required by the projection system.

Therefore, if the area of the light source is large and the emitted light emits at a large angle, the etendue cannot be reduced by using any optical system to which a Lagrange Invariant is applied.

This is the limit of the light collection efficiency limited by the etendue of the light source, and the actual system cannot exceed this theoretical efficiency.

In addition, the illuminated light receiving unit may calculate the etendue, and the projection engine may calculate the etendue of the MD (micro display) panel.

At this time, when the etendue of the light source is larger than the etendue of the light source calculated in the area of the light receiving unit and the F / # to be used, there is a problem that a light beam having an etendue difference cannot be accepted by the light receiving unit.

As the efficiency of the lighting device is limited through the etendue of the light source and the etendue of the light receiving unit, the lighting designers are seriously considering the etendue.

Among them, a study of using an LED instead of an arc lamp used as the light source is in progress.

In other words, arc lamps have long life, miniaturization, light weight, fast response speed, low voltage driving, and wide color range, instead of the arc lamps, to solve the above problems caused by the difficulty of making them small because they are related to lamp life. LEDs having such characteristics have been examined as light sources for projection engines (US Pat. No. 6,224,216).

However, the LED has not yet been able to give enough light output with a single device, it is necessary to secure the required light output using a plurality of LEDs.

In order to solve this problem, if a plurality of LEDs are used to secure the light output, the LEDs also have the aforementioned etendue, which causes a problem that the etendue of the entire light source increases due to the use of multiple LEDs. Therefore, even if a plurality of LEDs are used, there is a problem in that the etendue of the entire light source is increased to secure necessary light output.

Accordingly, the present invention has been made to solve the above problems, an object of the present invention to provide a lighting device that does not increase the etendue even when using a plurality of light sources, and to provide a projection display device using the same. There is a purpose.

Another object of the present invention is to use a plurality of LEDs in place of an arc lamp in the illumination system used in the projection display device.

Still another object of the present invention is to provide a lighting device that minimizes the etendue of the entire light source by securing a high light output by configuring less than the sum of the surface area constituting the etendue of each of the total light source is composed of a plurality of planes To provide.

A feature of the lighting apparatus according to the present invention for achieving the above object is a waveguide having a rod shape and the light is uniformized through the total reflection of the light incident to the inside and the light emitted to one side, the light is contacted to the outer surface of the waveguide A lighting device comprising at least one light source having at least one light emitting into a waveguide, wherein the waveguide from which the light exits is the sum of the surface areas constituting the etendue of each of the total light sources having an area of one side mounted on the outer surface of the waveguide. It is made smaller.

At this time, the light source is composed of an LED, the waveguide is preferably composed of at least one of a rectangular, solid, cylindrical, hemispherical, polygonal box form.

In addition, the waveguide from which the light is emitted is preferably configured such that the area of one side is smaller than the sum of the surface areas constituting the etendue of each of the light sources mounted on the outside of the waveguide.

In addition, the waveguide preferably has grooves in the shape of the light source, the grooves of which are equal to or larger than the size of the light source, and at least one light source contacts each of the grooves.

And a refractive index layer positioned between the waveguide and the light source with a material having a refractive index different from that of the light source to reduce the loss of light emitted from the light source.

In this case, the refractive index layer preferably has a refractive index value smaller than the refractive index of the light source and larger than the refractive index of the waveguide, or has a refractive index value larger than the refractive index of the light source.

In addition, the light source is preferably composed of at least one light source of different colors.

A feature of the projection display device according to the present invention for achieving the above object is configured as described above to condense the light emitted in each of the red (R), green (G) and blue (B) to reduce the size of the imager ( at least one illumination device uniformly shining on the imager, and each light emitted from the illumination device, and the synthesized image is enlarged through the projection lens system to enlarge the imager to form an image on the screen. It is configured to include.

In addition, another feature of the projection display device according to the present invention for achieving the above object is a lighting device for condensing the emitted light to uniformly illuminate the imager of a small size, and the imager It is composed of a projection lens system that greatly enlarges the image to form on the screen.

In this case, the lighting device is composed of at least one light source of a different color, to form an image for each color through the control of the plurality of light sources, synthesize each of the images formed in this way into a single image, and then immediately project It is preferable to emit light synthesized by the lens system.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments with reference to the accompanying drawings.

A preferred embodiment of a lighting device and a projection display device using the same according to the present invention will be described with reference to the accompanying drawings.

1A to 1C are a first embodiment showing the structure of a lighting device according to the present invention.

As shown in Figure 1a, b, c, the lighting device 100 according to the present invention has a rod shape, the light is uniform through the total reflection of the light incident to the inside and the waveguide 10 is emitted to one side 30, and At least one contact with the outer surface of the waveguide 10 is composed of a light source 20 for emitting light into the waveguide.

At this time, the light source 20 is composed of LED, the waveguide 10 is configured in the form of a rectangular parallelepiped having a surface on which light is emitted.

In addition, the waveguide 10 is configured such that the area of the emitting surface is smaller than the sum of the total surface areas constituting the etendue of each of the entire light sources attached to the outside. In this configuration, the etendue of the light source emitted from the light exit surface becomes smaller than the sum of the etendues of the light sources formed outside the waveguide.

In addition, since most light sources generate heat simultaneously with light emission, a heat dissipation structure is required. Therefore, it is preferable that the waveguide 10 is made of a material having high thermal conductivity to favor heat radiation. In addition, a heat sink may be attached to the outer surface of the waveguide 10 to increase heat dissipation.

2a to 2d are second embodiments showing the structure of the lighting apparatus according to the present invention.

As shown in Figure 2a, b, c, d, the illumination system 200 used in the projection display device according to the present invention has a rod shape and the light is uniformized through the total reflection of the light incident into the interior is emitted to one side 30 Waveguide 10 is formed in a solid shape and at least one contact with the outer surface of the waveguide 10 is composed of a light source 20 for emitting light into the waveguide.

At this time, the light source 20 is composed of LED, the waveguide 10 is configured in the form of a box-shaped box having a surface on which light is emitted. In addition, since most light sources generate heat simultaneously with light emission, the waveguide 10 is preferably made of a material having high thermal conductivity to dissipate heat. In addition, a heat sink may be attached to the outer surface of the waveguide 10 to increase heat dissipation.

In addition, by constructing the waveguide 10 in a solid shape, the light emitted from the light source 20 is reduced in the number of times reflected from the inner surface of the device can reduce the amount of light lost during reflection. In addition, as shown in FIG. 2 (d), the light emitted from the light source may be reflected on the reflection surface of the solid shape, thereby alleviating the angle of the light emitted in the emission direction.

In this case, when the waveguide 10 is continuously formed as the waveguide 10 is long, the area of the surface emitted from the light source may be larger than the sum of the surface areas of all light sources attached to the outside of the waveguide. However, as shown in FIG. 2 (d), since the angle of the light is relaxed in the emission direction, the etendue of the light source emitted from the illumination device causes the etendue of all light sources constituting the etendue of each light source attached to the outside of the waveguide 10. It will be formed smaller than the Tendu.

Therefore, even when the waveguide 10 is formed in a solid shape, the etendue of the entire illumination system becomes smaller than the sum of the etendues of the entire light sources, and, when the waveguide is formed in a rectangle in the first embodiment, The tender can be made smaller, and thus the efficiency of the light source can be further increased.

3A and 3B are a third embodiment showing the structure of a lighting apparatus according to the present invention.

3A and 3B, at least one light source 20 for emitting light and a rod-shaped groove having an outer surface in the shape of the light source 20 and emitting light at each light source positioned in the groove are formed. It consists of a wave-shaped waveguide 10 of the shape of the light is uniformed through the total reflection and emitted to one side (30).

That is, as shown in FIG. 3A, a groove 40, which is equal to or slightly larger than the size of the light source, is formed on the outer surface of the waveguide 10 in which the at least one light source 20 is to be located. Then, the light source is contacted with the formed groove 40 to form a lighting device having a structure as shown in FIG. 3B.

At this time, the light source 20 is composed of an LED, and the LED generates heat simultaneously with light emission, so that the waveguide 10 is made of a material having high thermal conductivity for heat dissipation. In addition, a heat sink may be attached to the outer surface of the waveguide 10 to increase heat dissipation.

In the third embodiment, the waveguide 10 is a solid waveguide, but may be configured as a rectangular waveguide.

However, in the case where the waveguide 10 is formed in a solid shape, the etendue can be made smaller than in the case where the waveguide is formed in a rectangle in the first embodiment as described in the second embodiment. There is an effect that can further increase the efficiency.

4 is a fourth embodiment showing the structure of a lighting apparatus according to the present invention.

As shown in FIG. 4, the illumination system 200 used in the projection display device according to the present invention has a rod shape and has a waveguide 10 which is uniformed through total reflection of light incident thereinto and is emitted to one side 30. A light source 20 which contacts at least one outer surface of the waveguide 10 to emit light into the waveguide, and a material having a refractive index different from that of the light source 20, between the waveguide 10 and the light source 20. It is composed of a refractive index layer 50 to reduce the loss of light emitted from the light source.

In this case, the refractive index layer 50 has a refractive index value smaller than the refractive index of the light source 20 and larger than the refractive index of the waveguide 10, or a gel having high thermal conductivity having a refractive index value larger than the refractive index of the light source 20. The material in form is preferably composed of silicone gels.

That is, in the case of the light source 20 made of a material having a high refractive index such as an LED, the total amount of light reflected by the difference in refractive index at the interface between the light source and the waveguide decreases the efficiency. Therefore, as in the first case, a refractive index layer 50 having a refractive index smaller than the refractive index of the light source and larger than the waveguide refractive index is formed between the light source 20 and the waveguide 10 so that the light source 20 and the waveguide 10 are different due to the difference in refractive index. It is possible to improve the light emission efficiency by eliminating the total reflection generated between the).

In addition, as in the second case, when the refractive index of the refractive index layer 50 is larger than the refractive indexes (2.4 to 3) of the light source, this effect is exhibited. That is, when the light emitted from the light source 20 with an acute angle passes through the refractive index layer 50 having a refractive index greater than that of the light source 20, the light is refracted to emit an obtuse angle. Since light having an acute angle emitted from the light source 20 through the refractive index layer 50 is refracted to have an obtuse angle and is incident to the waveguide 10, the probability of occurrence of total reflection of light incident to the waveguide can be reduced. Efficiency can be increased.

The refractive index layer 50 formed as described above may be applied to all of the illumination systems having the structures of the first to third embodiments described above, and thus may further increase the light emission efficiency.

The light source 20 is composed of LEDs, and the waveguide 10 is configured in the form of a box having one side from which light is emitted. At this time, the waveguide 10 may be configured as a waveguide of the solid shape as in the second embodiment.

As such, when the waveguide 10 is formed in the shape of a shell, it is possible to form the etendue smaller than in the case of forming the waveguide in a rectangular shape as described in the second embodiment, thereby further increasing the efficiency of the light source. It can be effective.

In addition, since most light sources generate heat simultaneously with light emission, the waveguide 10 is preferably made of a material having high thermal conductivity to dissipate heat. In addition, a heat sink may be attached to the outer surface of the waveguide 10 to increase heat dissipation.

In addition, by configuring more LED light source 20 in the long waveguide 10 as shown in Figure 5a, b, it is possible to configure a lighting device capable of outputting a sufficient amount of light.

In addition, although the shape of the waveguide 10 is limited to rectangular and solid shapes in the above embodiment, the reflective surface may be formed in a cylindrical, hemispherical, or polygonal shape.

The projection display device may be configured of a projection system in which illumination light is incident on each panel by inputting light emitted through the illumination device configured as described above, and a color is separated by a color wheel or a dichroic mirror to form an image on a screen.

6 is a first embodiment showing a projection display apparatus using a lighting apparatus according to the present invention.

As illustrated in FIG. 6, the projection display apparatus may be roughly divided into an illumination system 100 and a 200 and a projection system 300.

As shown in FIG. 7A, the illumination system 100 condenses a light waveguide having a predetermined shape, a lighting device 100 including a plurality of LED light sources outside the waveguide, and collects light emitted from the lighting device 100. It consists of an integrator 110 that evenly shines on an imager of size.

In addition, the projection system 300 is combined with the color selection polarizer 330, the dichroic filter 320, and the LCD panel 310 to change the path of the light emitted from the illumination system 100 and 200 and change the color. A color separation / synthesis unit for forming a star image, and synthesizing each image thus formed into a single image, and a projection lens system for enlarging an image synthesized in the color separation / synthesis unit through the imager and forming an image on a screen. 340.

In this case, the illumination system is generally not uniform in intensity of light emitted from the lighting device as shown in Figure 7a is the intensity of light in the direction of the optical axis is stronger and the light intensity becomes weaker as the distance away from the optical axis, uniform light An integrator 110 is provided to emit light. In this case, a lens may be used to adjust the width of the light.

However, as another embodiment according to the present invention, as shown in 7b, when the waveguide 10 is formed in an elongated form without further configuring the integrator, when light emitted through the LED light source is emitted from the outside of the elongated waveguide, The reflection of the long waveguide allows for the equalization of light instead of integrators. At this time, it is preferable to reduce the width of the waveguide to the same width as the conventional integrator 110.

Through this, an effect of simplifying the structure of the projection display apparatus may be obtained.

In addition, if a plurality of LED light sources formed in the waveguide are configured as LED light sources of some or each different color (R, G, B), and control them according to the color-specific image, the display device using the lighting device more It can be configured briefly.

8 is a first embodiment showing a projection display apparatus using a lighting apparatus according to the present invention, showing a transmissive three-plate type.

9 is a second embodiment showing a projection display device using the lighting apparatus according to the present invention, and shows a DLP single plate type.

As shown in Figs. 8 and 9, each of the red (R), green (G), and blue (B) lights from the three lighting devices (100a) (100b) and (100c) is a respective LCD panel in the three-plate type. Via 310 is irradiated to the composite portion 320 which is an X-type prism, in the case of a single plate type is directly irradiated to the composite portion 320.

The image synthesized by the combining unit 320 forms an image on a screen by enlarging the imager through the projection lens system 340.

Therefore, in the conventional lighting device, the light source to be irradiated can use only white light, so that it should be separated into RGB through a separate color separation means, and the separated RGB should be irradiated to the combining unit. In the case of using a lighting device using a distinguishable LED light source, it is possible to remove a separate color separation means to block the light leakage through the color separation means to increase the light efficiency.

FIG. 10 is a third embodiment showing a projection display apparatus using a lighting apparatus according to the present invention. In FIG. 10, the projection display apparatus removes not only the color separation apparatus but also the synthesis unit.

That is, as shown in FIG. 10, the image for each color is formed through the control of the plurality of LED light sources, and each image is thus synthesized into one image, and then the light synthesized by the projection lens system 340 is immediately emitted. It is made up for. Accordingly, the effect of greatly simplifying the structure of the projection display apparatus can be obtained.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

As described above, the lighting device and the projection display device using the same according to the present invention have the following effects.

First, by using the proposed lighting device, it is possible to form a lighting device having a sufficient amount of light while minimizing etendue by using a plurality of light sources lacking light quantity.

Second, even when a single light source provides an insufficient amount of light by using one of the proposed lighting devices, a projection display device having a sufficient amount of light can be configured by using multiple light sources.

Third, the structure of the projection display apparatus can be greatly simplified by removing the existing color separation / synthesis unit from the lighting apparatus which requires a color synthesizing apparatus by configuring a plurality of light sources with light sources of some or different colors.

Claims (17)

A waveguide having a rod shape and having light uniformed through total reflection of light incident into the inside, In the illumination device comprising a light source having at least one or more in contact with the outer surface of the waveguide to emit light into the waveguide, The waveguide from which the light is emitted is an illumination device, characterized in that the area of one side is configured to be smaller than the sum of the surface areas constituting the etendue of each of the total light sources mounted on the outer surface of the waveguide. The method of claim 1, The illumination device, characterized in that the light source is composed of LED. The method of claim 1, The waveguide is a lighting device, characterized in that consisting of at least one of a rectangular, solid, cylindrical, hemispherical, polygonal box shape. delete The method of claim 1, The waveguide is characterized in that it has a high thermal conductivity. The method of claim 1, The waveguide is formed in the shape of the light source, the illumination device, characterized in that to form a groove on the outer surface of the same or larger than the size of the light source and to contact the at least one light source, respectively. The method of claim 1, And a refractive index layer disposed between the waveguide and the light source with a material having a refractive index different from that of the light source to reduce a loss of light emitted from the light source. The method of claim 7, wherein And the refractive index layer has a refractive index value smaller than the refractive index of the light source and larger than the refractive index of the waveguide. The method of claim 7, wherein And the refractive index layer has a refractive index value greater than that of the light source. The method of claim 7, wherein The refractive index layer is an illumination device, characterized in that consisting of a gel-like material having a high thermal conductivity. The method of claim 10, The refractive index layer is an illumination device, characterized in that consisting of a silicone gel. The method of claim 1, And the light source comprises at least one light source of different colors. At least one lighting device configured as described in claim 1 to focus the light emitted in each of the red (R), green (G) and blue (B) to uniformly illuminate the imager of a small size, And synthesizing each light emitted from the illumination device, and the synthesized image comprises a projection system for enlarging the imager through a projection lens system to form an image on a screen. The method of claim 13, The projection system is a projection display device, characterized in that any one of the transmissive three-plate type, DLP single plate type. The lighting device is configured as described in claim 1 to condense the emitted light to uniformly illuminate the imager of a small size, And a projection lens system which enlarges the imager and forms an image on a screen. The method of claim 15, The illumination device is a projection display device further comprises an integrator or FEL to increase the uniformity of the emitted light. The method of claim 15, The at least one lighting device includes at least one light source having a different color, forms an image for each color through the control of the plurality of light sources, synthesizes each of the formed images into a single image, and then directly to the projection lens system. A projection display device characterized by emitting a synthesized light.

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