KR100699159B1 - Projection system - Google Patents

Abstract

The present invention relates to a projection system, wherein the light emitted from the light source in the projection system selectively reflects the first or second reflection area of the light beam exiting part according to its radiation angle and then reflects the light, so that a rectangular light beam is emitted. By doing so, a very small projection system can be realized.

According to the present invention, there is provided a plurality of light source units spaced apart from each other and emitting light of different wavelengths, a plurality of light beam emitters covering each light source unit and emitting light emitted from each light source unit into a rectangular light beam, and each light beam. A plurality of LCDs for transmitting the light emitted by the exit unit, a photosynthesis unit for synthesizing the light transmitted by the plurality of LCDs, and a projection lens for projecting the light synthesized by the photosynthesis unit on the screen to emit light emitted from the light source unit. It can be efficiently used, reduces the number and space of optical components for implementing the system, and increases the reliability and luminance of the light emitted from the light source by using the light emitting element as a light source.

Light emitting element, projection, LCD

Description

Projection system

1 is a view showing the configuration of a projection system using a conventional arc discharge lamp as a light source.

2 is a view showing in detail the configuration of the arc discharge lamp of FIG.

3 is a diagram showing the configuration of a projection system of the present invention.

4A and 4B are views showing details of a first reflection area in the light beam exit part of FIG. 3;

5A and 5B are views showing details of a second reflection area in the light beam exit part of FIG. 3;

6A and 6B are detailed views of the light beam exit part of FIG. 3.

* Description of symbols on the main parts of the drawings *

300, 330, 360: light source unit. 310, 340, 370: light beam exit unit.

311, 341, 371: first reflection area. 312, 342, 372: second reflection area.

320, 350, 380: LCD. 390: photosynthesis part.

395: projection lens.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection system. In particular, in implementing a projection system, a second reflection area and a first reflection area are used to effectively use light emitted by a plurality of light source parts spaced apart from each other and emitting light having different wavelengths. The present invention relates to a projection system capable of realizing a microscopic projection system by using a light beam emitter that combines regions to emit a rectangular light beam.

Projection system is to implement a small image on a large screen by using optical means. According to the type of device to implement the image, CRT (Cathode Ray Tube) projection, LCD (Liquid Crystal Display) projection and DLP (Digital Light Processing) projection It is divided into ways.

The CRT projection method is a method in which an image is formed on a screen by reflecting a small high definition CRT on a mirror. In the LCD projection method, when an externally reproduced video signal is sent to a projection TV, a small LCD screen having a diameter of about 4 inches inside the projection TV is received and reproduced. Then, the image formed on the screen is shot with strong light from behind the LCD screen. Zoom in on the screen and reflect it on the mirror to project on the screen. The DLP projection method operates by enlarging and projecting an image signal input from the outside by using a digital micromirror device (DMD) semiconductor chip in which hundreds of thousands of fine driving mirrors are integrated.

The LCD projection method is currently in the spotlight and is widely used. Since the LCD is not a light emitting device, a light emitting source is required to display an image on the screen. However, in the related art, since an arc discharge lamp is used as a light emitting source, it is not suitable for implementing a miniaturized projection system because many optical parts and space are required to implement a screen with the light emitting source.

This conventional technique will be described with reference to FIG. 1.

1 is a view showing the configuration of a projection system using a conventional arc discharge lamp as a light source. As shown, the arc discharge lamp 100 excites mercury gas using arc discharge and emits light while falling to the ground state. The emitted light is output in parallel to the optical axis 100LC.

On the other hand, Figure 2 is a view showing the configuration of the arc discharge lamp of FIG. As shown in the figure, the arc discharge lamp includes a light source lamp 200 that emits light and a concave mirror 210 that reflects the light emitted from the light source lamp 200 to be emitted in parallel to the optical axis 100LC. .

The light source lamp 200 is excited by the mercury gas present in the interior due to the arc discharge falls to the ground state of the minimum energy. As a result, a difference between the potential energy before the mercury gas is excited and the potential energy after the excitation is generated, and light corresponding to the difference in the generated energy is emitted.

The concave mirror 210 receives light emitted from the light source lamp 200 and reflects the light parallel to the optical axis 100LC, and has a parabolic cross section in the direction in which the light is emitted. That is, the curvature of the concave mirror 210 should be a value such that light emitted at the position of the focal point, which is the position of the light source lamp 200 that emits light, is emitted in parallel to the optical axis 100LC.

The light emitted from the light source is more homogenized through the two fly eye lenses 102 and 104 and the first lens 106. The first fly's eye lens 102 and the second fly's eye lens 104 are formed of a plurality of small lens arrays to convert the light emitted from the arc discharge lamp 100 into a plurality of partial lights. The plurality of partial lights becomes homogeneous light through the first lens 106.

The light homogeneously formed by the first lens 106 is transmitted in the first dichroic mirror 108, and red light is transmitted and light of the remaining wavelength is reflected. The transmitted red light is reflected by the first mirror 110 and input to the first LCD 114 through the first dichroic lens 112.

The light reflected by the first dichroic mirror 108 is transmitted through the blue light and the green light is reflected by the second dichroic mirror 116. The reflected green light is input to the second LCD 120 through the second dichroic lens 118.

The blue light transmitted from the second dichroic mirror 116 passes through the second lens 122 and is reflected by the second mirror 124, and the reflected blue light passes through the relay lens 126 and passes through the third mirror. Is reflected at 128. The blue light reflected by the third mirror 128 is input to the third LCD 134 through the fourth lens 130 and the polarizer mirror 132. Since the relay lens 126 is used to input blue light into the third LCD 134 because the length of the light path of the blue light is longer than that of the light of the other color, the reduction of light utilization efficiency due to light diffusion or the like is prevented. To do this.

The red, green, and blue light input to the three LCDs 114, 120, and 134 are transmitted and synthesized in a cross dichroic prism 136. The synthesized light is projected on the screen by a projection lens 138 having a function as a projection optical system.

However, in the case of the projection system using the light emitted from the conventional arc discharge lamp as a light source, a large number of optical components are required to implement a screen, and thus the area of space required for providing the optical components in the projection system. This increases. In addition, in the case of the arc discharge lamp, its lifetime is not long, such as 1000 to 10000 hours, so when the user watches a long time image using the projection system, the reliability and luminance of the light emitted from the arc discharge lamp deteriorates and thus the arc discharge lamp There is a problem that must be replaced frequently.

Therefore, in recent years, there is an increasing number of fields requiring a small projection system such as a mobile communication terminal. However, there is a inconvenience that the implementation of the projection system using the conventional arc discharge lamp as a light source is impossible.

Therefore, an object of the present invention is to efficiently reflect the light emitted from the light source of the projection system to the first reflection area or the second reflection area of the light beam exiting part according to the radiation angle so that the rectangular light beam is emitted. And the number and space of optical components required to implement the projection system is reduced. In addition, since the lifespan of the light emitting device is increased by using the light emitting device, the reliability and luminance of the light emitted from the light source are increased to provide a projection system that enables a microscopic projection system.

The projection system of the present invention having the above object comprises a plurality of light source units spaced apart from each other and emitting light of different wavelengths, and a plurality of light beam emitting units covering each light source unit and emitting light emitted from each light source unit into a rectangular light beam. And a plurality of LCDs for transmitting the light emitted by each of the light beam exit units, a photosynthesis unit for synthesizing the light transmitted by the plurality of LCDs, and a projection lens for projecting the light synthesized by the photosynthesis unit on the screen. It features.

The light source unit may emit light having a large distribution of emission angles.

The light source unit may include one or more light emitting diodes.

The photosynthetic unit is a cross dichroic prism.

The light having different wavelengths may be light of blue wavelength, light of green wavelength, or light of red wavelength.

A first reflection region having a curvature for receiving light having a radiation angle greater than a reference angle among the light emitted from the light source unit and reflecting the light to be emitted parallel to the optical axis, and is attached to a lower surface of the first reflection region, And a second reflection area having a curvature for reflecting light having a radiation angle smaller than a reference angle among the light emitted by the light source unit to be reflected in parallel with the optical axis.

The reference angle is characterized in that 30 degrees.

The first reflection area has a hollow shape having a first surface having a circular opening, a second surface facing the first surface and having a circular opening, and an outwardly curved sidewall connecting the first and second surfaces. Projection system characterized in that.

The second reflection area is a hollow surface having a first surface having a rectangular opening, a second surface facing the first surface and having a circular opening, and an outwardly curved sidewall connecting the first and second surfaces. Projection system characterized in that.

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

3 is a diagram showing the configuration of a projection system of the present invention. As shown, the light emitting device units 302, 332, and 362 are formed on the substrates 301, 331, and 371 spaced apart from each other, and the light emitting device units 302, 332, and 362 emit light having different wavelengths. A plurality of light source units 300, 330, and 360, and light emitting element units 302, 332, and 362 of the light source units 300, 330, and 360, respectively, emit light emitted from each of the light source units 300, 330, and 360. A plurality of light beam emitters 310, 340, and 370 that emit light with a rectangular light beam; and a plurality of LCDs 320, 350, which transmit light having different wavelengths emitted by each of the light beam emitters 310, 340, and 370; 380, a photosynthesis unit 390 for synthesizing light having different wavelengths transmitted by the plurality of LCDs 320, 350, and 380, and a projection lens for projecting the light synthesized by the photosynthesis unit 390 onto a screen ( 395).

The light source units 300, 330, and 360 are formed by attaching light emitting element units 302, 332, and 362 to upper surfaces of the substrates 301, 331, and 361. The substrates 301, 331, and 361 are submounts or printed circuit boards (PCBs) capable of semiconductor processing. The submount uses a semiconductor substrate such as silicon (Si), an insulator substrate such as aluminum nitride (AlN), or a conductive substrate. The upper surfaces of the substrates 301, 331, and 361 are attached to each other by bonding or the like so that one or more light emitting devices are formed apart from each other. When the substrates 301, 331, and 361 are conductive substrates, an insulating material is formed on the upper surfaces of the substrates 301, 331, and 361, and then one or more light emitting devices are bonded.

The light source units 300, 330, and 360 which emit light having different wavelengths are formed to be spaced apart from each other. The image projected by the projection system must be able to display all colors. Each of the light emitting device portions formed in the plurality of light source parts 300, 330, and 360 spaced apart to display all colors, the light emitting device portion 302 emitting light of a green wavelength, and the light emitting devices emitting light of a red wavelength. And a light emitting element portion 362 that emits light having a blue wavelength. This is because all the colors can be expressed by the combination of the three colors. That is, the light source unit 300 emitting green light, the light source unit 330 emitting red light, and the light source unit 360 emitting blue light should be formed to be spaced apart from each other.

One or more light emitting elements constituting each light emitting element portion is not necessarily limited to light emitting elements emitting light of a wavelength emitted by the light source portion. That is, the light emitted by each light emitting device constituting the light emitting device unit may be applied to the present invention even if blue, green, or red light is expressed by mixing light emitted by the plurality of light emitting devices at the time of emitting light.

In the light emitting device, when a forward voltage is applied between the p-electrode layer (not shown) and the n-electrode layer (not shown), the light emitting element is formed from the n-type electrode layer through the n-type layer (not shown) to the active layer (not shown). Electrons are injected, and holes are injected into the active layer from the p-type electrode layer through the p-type layer (not shown). In this case, electrons and holes injected into the active layer recombine with each other to emit light corresponding to a bandgap or energy level difference of the active layer. In this way, since the light emitting device takes the form of surface emission, the light source units 300, 330, and 360 emit light having a large distribution of radiation angles.

The light beam emitters 310, 340, and 370 cover the light emitting element units 302, 332, and 362 of the light source units 300, 330, and 360, and emit light emitted from the light source units 300, 330, and 360. A light beam that is rectangular in a plane parallel to the optical axis and perpendicular to the optical axis is emitted.

Since the light emitted from each light source unit 300, 330, 360 has a large distribution of the radiation angle, the light having the larger emission angle among the light emitted from the light source unit 300, 330, 360 is a light beam exit unit 310, 340, 370. Should be reflected parallel to the optical axis. Therefore, the light beam emitters 310, 340, and 370 receive and emit light emitted from the light source units 300, 330, and 360 from the first reflection areas 312, 342, and 372 so that they are emitted in parallel to the optical axis. In the above, light having a large emission angle is light whose emission angle is 30 degrees or more.

4A and 4B are diagrams illustrating the first reflection area in detail in the light beam exit part of FIG. 3. 4A is a perspective view of a first reflection area. As shown, the first reflection area is spaced apart from the first surface 400 having the first circular opening 411 and is opposed to the first surface 400 and has the second circular opening 412 formed therein. The second surface 410 and the first surface 400 and the second surface 410 is connected to the hollow shape is formed with a sidewall 420 curved outward. The second circular opening 412 of the second surface 410 is an opening for covering the light emitting element portion constituting the light source portion. The sidewalls 420 are curved outwardly to reflect the light emitted from the light source to be emitted parallel to the optical axis after the sidewalls are incident. Since the emission angles of the light emitted by the light source unit are different, the incident angles of the side walls 420 are also different. This results in a change in curvature rather than a fixed curvature in the sidewalls.

4B is a rear view of the first reflection area. As shown, the centers of the first surface 400 and the second surface 410 are on one collinear line. That is, in the vertical direction of the first surface 400, the center of the first surface 400 and the center of the second surface 410 exist on the same line.

Among the light emitted from the light source units 300, 330, and 360, the light emission beams 310, 340, and 370 having a small emission angle should be reflected and emitted parallel to the optical axis. In this case, since a screen of an image display device is generally formed in a rectangular shape, light having a small radiation angle is incident and reflected from the second reflection areas 311, 341, and 371 in order to emit a rectangular light beam in a plane perpendicular to the optical axis. do. The homogenized light is emitted due to the second reflection areas 311, 341, 371. Light having a small emission angle is light whose emission angle is 30 degrees or less. However, light having an emission angle of about 0 to 5 degrees is not reflected in the second reflection areas 311, 341, and 371. This is because the light emitted from the light source unit is incident on the LCDs 320, 350, and 380 before being incident on the second reflection areas 311, 341, and 371.

5A and 5B illustrate the second reflection area in detail in the light beam exit part of FIG. 3. 5A is a perspective view of a second reflection area. As shown, the second reflection area includes a first surface 500 having a rectangular opening, a second surface 510 facing the first surface 500 and having a circular opening, and the first surface ( It is a hollow shape connecting the 500 and the second surface 510 and the outwardly curved sidewall 520 is formed. A first reflection area is attached to an upper portion of the circumference of the opening of the second surface 510. Since the curvature of the side wall 520 is changed, and the opening of the first surface 500 is a quadrangular shape, the light reflected and emitted by the second reflective region is a quadrangular light beam.

5B is a rear view of the second reflection area. As illustrated, when the edge of the second surface 510 is projected onto the first surface 500, the edge of the second surface 510 is included in the edge of the first surface 500. That is, when the second surface 510 is projected onto the first surface 500, the second surface 510 is included in the first surface 500. In addition, the centers of the first surface 500 and the second surface 510 exist on one collinear line. That is, the center of the first surface 500 and the center of the second surface 510 exist in the same line in the vertical direction of the first surface 500.

6A and 6B are detailed views illustrating the light beam exit part of FIG. 3. 6A is a perspective view of the light beam exit unit. As shown in the drawing, the light beam exiting part is attached to the lower surface of the first reflecting area and is attached.

6B is a side view of the light beam exit section. As shown in the drawing, the first reflection area and the second reflection area have a shape connected by one curve. That is, the 1st reflection area | region and 2nd reflection area | region exactly adhere | attach and are attached.

The LCDs 320, 350, and 380 transmit light having different wavelengths emitted from the light beam emitters 310, 340, and 370. The LCDs 320, 350, and 380 are called thermotropic liquid crystals (ie, thermotropic liquid crystals) between two sheets of glass, that is, varying the amount of light passing through the liquid crystals depending on the degree of twisting of the organic compound that becomes a liquid crystal at a certain temperature range. To display the screen. The degree of twist of the liquid crystal is determined by the voltage applied to the LCD. That is, the transmittance of light is determined by the voltage applied to the LCD to display an image of a color screen.

The photosynthesis unit 390 synthesizes light transmitted through the LCDs 320, 350, and 380. The photosynthesis section 390 has a function as a color light synthesizing means for forming a color image by synthesizing three colors of light, such as a cross dichroic prism, for example. In the cross dichroic prism 390, a dielectric multilayer film 392 reflecting red light and a dielectric multilayer film 394 reflecting blue light are formed in an X-shape at the interface between four rectangular prisms. By these dielectric multilayer films 392 and 394, three color lights are synthesized, and synthesized light for projecting a color image is formed.

The projection lens 395 projects the light synthesized by the photosynthesis unit 390 on the screen. The projection lens 395 has a function as a projection optical system, and displays the image on the screen by enlarging and projecting the composite light generated by the photosynthesis unit 390 on the projection screen.

On the other hand, while the present invention has been shown and described with respect to specific preferred embodiments, various modifications and changes of the present invention without departing from the spirit or field of the invention provided by the claims below It can be easily understood by those skilled in the art.

As described above, the projection system of the present invention can efficiently use the light emitted by the light source unit, and can reduce the number and space of optical components required to implement the projection system, thereby enabling the implementation of a very small projection system. In addition, since the lifespan is increased by using the light emitting element as a light source, the reliability and luminance of light emitted from the light source is increased.

Claims (13)

A plurality of light source units spaced apart from each other and emitting light of different wavelengths; A plurality of light beam emitters covering the light source units and emitting light emitted from each light source unit into a rectangular light beam; A plurality of LCDs for transmitting the light emitted from each of the light beam exit units; A photosynthesis unit for synthesizing the light transmitted by the plurality of LCDs; And And a projection lens for projecting the light synthesized by the photosynthesis unit onto the screen. The method of claim 1, And the light source unit emits light having a large distribution of radiation angles. The method of claim 2, And the light source unit is composed of one or more light emitting diodes. The method of claim 1, And the photosynthesis part is a cross dichroic prism. The method of claim 1, And the light having different wavelengths is light of blue wavelength, light of green wavelength, light of red wavelength. The method of claim 1, wherein the light beam exit unit A first reflection region having a curvature for receiving light having a radiation angle greater than a reference angle among the light emitted by the light source unit and reflecting the light to be emitted in parallel with the optical axis; And And a second reflection area having a curvature for reflecting light having a radiation angle smaller than a reference angle among the light emitted by the light source unit to be reflected in parallel with the optical axis. The method of claim 6, The reference angle is a projection system, characterized in that 30 degrees. The method of claim 6, The first reflective region is spaced apart from the first surface having a first circular opening, facing the first surface, and having a second circular opening, and outwardly connecting the first and second surfaces. Projection system, characterized in that the hollow side is formed with a curved side wall. The method of claim 8, And the area of the first surface is greater than the area of the second surface. The method of claim 9, And a center of the first surface and a center of the second surface in the same line in the vertical direction of the first surface. The method of claim 6, The second reflection area is a hollow surface having a first surface having a rectangular opening, a second surface facing the first surface and having a circular opening, and an outwardly curved sidewall connecting the first and second surfaces. Projection system, characterized in that consisting of. The method of claim 11, And projecting the edge of the second surface onto the first surface, wherein the edge of the second surface is included in the edge of the first surface. The method of claim 12, And a center of the first surface and a center of the second surface in the same line in the vertical direction of the first surface.

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