KR101099327B1 - Laser light source and scanning display apparatus having the same - Google Patents

Abstract

The present invention relates to a laser scanning display apparatus, wherein the laser scanning display apparatus according to the present invention includes a first laser (111) for generating a first laser light, a second laser (121) for generating a second laser light, and And reflecting the third laser 131 generating the third laser light and the laser light emitted from each of the lasers 111, 121 and 131 within a predetermined angle range to scan in the horizontal direction of the screen S. And a polyhedron mirror 150 and a galvano mirror 160 for scanning each laser light in the vertical direction of the screen S. Each laser includes a laser diode 113 for generating laser light and a laser diode ( Controls the current supplied to the laser diode 113 so that the light output of the laser light emitted from the laser diode 113 and the OPS chip 115 reflects the laser light modulated by the laser light incident from the 113 Current system It comprises the device. According to the present invention having such a configuration, since the laser light of the output corresponding to the gray scale of the image to be expressed is generated by controlling the current applied to the laser, it is possible to prevent the decrease in efficiency.

Laser Scanning Display, Laser Light Source, Current Control, OPS Chip

Description

Laser light source and laser scanning display apparatus having the same {Laser light source and scanning display apparatus having the same}

1 is a configuration diagram schematically showing a configuration of a conventional laser scanning display device.

2 is a configuration diagram schematically showing the configuration of a laser scanning display device according to a preferred embodiment of the present invention.

3 is a diagram schematically illustrating a configuration of a laser provided in the laser light source shown in FIG. 2.

FIG. 4 is a diagram illustrating an essential component of the laser shown in FIG. 3.

<Description of Symbols for Main Parts of Drawings>

110,120,130; 1,2,3 Laser Source 111,121,131; 1,2,3 Laser

112,122,132; 1,2,3 current control device 115; OPS chip

141,142,143; 1,2,3 optical filter 150; polyhedron mirror

160; galvano mirror 170; mirror

The present invention relates to a display device, and more particularly, to an improved laser light source and a laser scanning display device having the same for improving efficiency of a display device and realizing high resolution.

In general, display apparatuses include a projection display apparatus which enlarges an image generated by a display element and forms an image on a screen, and a laser scanning display apparatus that generates an image by scanning laser light on a screen through a polyhedral mirror.

The projection display device may generate an image from a display device such as a liquid crystal display (LCD), a digital micromirror device (DMD), a grate light valve (GLV), a liquid crystal on silicon (LCos), and then display an optical image on the display device. Investigate and magnify it to form an image. Such a projection display device can obtain excellent image quality, but has a disadvantage in that the efficiency of the device is not good.

The laser scanning display apparatus generates an image by scanning laser light on an image forming surface of a screen, and the efficiency of the apparatus is good, but it is difficult to obtain excellent resolution and excellent image quality.

1 is a view schematically showing the configuration of a conventional laser scanning display device.

As shown in FIG. 1, a conventional laser scanning display apparatus includes a plurality of lasers 11, 12, 13, optical modulators 21, 22, 23 for adjusting the intensity of light, and a plurality of laser scanning display apparatuses. Optical filters 31, 32 and 33, a polyhedron mirror 40 for reflecting the laser light in the horizontal direction of the screen S, and a galvano mirror for scanning the laser light in the vertical direction of the screen S. And a galvanometer mirror 50.

Here, the first laser 11 generates a red laser light, the second laser 12 generates a green laser light, and the third laser 13 generates a blue laser light.

The laser light generated by each of these lasers 11, 12, 13 passes through the first to third optical modulators 21, 22, 23 provided on the optical path of each laser light. As the optical modulators 21, 22, and 23, an AOM (Aousto-Optic Modulator) is mainly used. The laser light incident on each of the optical modulators 21, 22, and 23 is a gray of an image. The intensity is modulated according to the gray scale.

The red, green, and blue laser light modulated through the optical modulators 21, 22, and 23 are subjected to a dichroic coating to have a transmissive or reflective characteristic according to the type of light. It is emitted to the third optical filters 31, 32, 33. Through the first to third optical filters 31, 32 and 33, the red, green, and blue laser beams form the same optical path and are incident on the polyhedral mirror 40 installed on the common optical path.

Each of the red, green and blue laser beams that have been advanced to the polyhedral mirror 40 is reflected in the horizontal direction while being reflected from the reflective surface of the polyhedron mirror 40 rotating at high speed. Each laser light reflected by the polyhedral mirror 40 is scanned by the galvano mirror 50 in the vertical direction of the screen S to form a two-dimensional image.

By the way, the conventional laser scanning display apparatus which uses the optical modulators 21, 22, 23 as mentioned above has disadvantages in various aspects, such as the aspect of efficiency or the aspect of image quality.

Specifically, since the intensity control of the laser light according to the gray scale is made through the optical modulators 21, 22, 23 after the laser light is emitted, regardless of the light and dark of the image formed on the screen S, Each of the lasers 11, 12, 13 continues to generate laser light of a constant power, which leads to waste of laser light and deterioration of efficiency.

And, in order to realize a high resolution image, the optical modulation should be made at a modulation rate of resolution * frame rate or more. However, the current optical modulator cannot implement a modulation rate of VGA or higher resolution and thus the image quality is degraded.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and does not use an optical modulator, so that the laser light is modulated by the red, green, and blue laser light itself to prevent efficiency degradation, and improved laser scanning to realize high resolution images. It is an object to provide a display device.

The laser light source according to the present invention for achieving the above object is a laser diode for generating a laser light, an OPS chip that receives the laser light from the laser diode and reflects the laser light modulated frequency, and emitted from the laser diode It includes a current control device for controlling the current supplied to the laser diode so that the light output of the laser light is changed.

Here, the current control device may control the current according to the gray scale of the displayed image.

The laser light source according to the present invention includes a harmonic nonlinear optical member which is installed on an optical path of the laser light reflected by the OPS chip and varies the frequency of the reflected laser light, and the laser light emitted from the laser diode is the OPS. It may further include a focusing lens provided between the laser diode and the OPS chip to be focused on the chip.

On the other hand, the laser scanning display device according to the present invention includes a first laser for generating a first laser light, a second laser for generating a second laser light, a third laser for generating a third laser light, and each of And a polyhedral mirror for reflecting the laser light emitted from the laser within a predetermined angle range to scan in the horizontal direction of the screen, and a galvano mirror for scanning the laser light in the vertical direction of the screen, wherein each laser includes: A laser diode for generating laser light, an OPS chip that receives the laser light from the laser diode and reflects the laser light whose frequency is modulated, and is supplied to the laser diode so that the light output of the laser light emitted from the laser diode is changed. It includes a current control device for controlling the current.

Here, the laser scanning display device according to the present invention comprises an optical filter disposed in the light output path of at least one laser light source of the plurality of laser light sources so that each laser light incident on the polyhedral mirror has the same incident light path. It may further include.

According to the present invention as described above, since the current control device controls the current supplied to the laser diode, the output of the laser light generated from the laser diode is varied according to the gray scale of the image displayed. Therefore, it is possible to reduce the waste of laser light and to increase the efficiency of the device.

In addition, by using the OPS chip, the modulation speed of the laser light can be increased, and high resolution and high quality images can be obtained.

Hereinafter, a laser light source and a laser scanning display apparatus having the same according to a preferred embodiment of the present invention will be described with reference to FIGS. 2 to 4.

2 is a configuration diagram schematically showing the configuration of the laser scanning display device according to a preferred embodiment of the present invention, Figure 3 is a schematic diagram showing the configuration of a laser provided in the laser light source shown in Figure 2, Figure 4 3 is a view showing an extract of the main components of the laser shown in FIG.

As shown in Figure 2, the laser scanning display device according to a preferred embodiment of the present invention, the first, second, third laser light source (110, 120, 130) for emitting a laser light and the output of the laser light First, second, third optical filters 141, 142, 143 for adjusting the optical path, a polyhedron mirror 150 for scanning the emitted laser light in the horizontal direction of the screen S, and a polyhedron mirror ( It includes a galvano mirror 160 for scanning the laser light reflected from the 150 in the vertical direction of the screen (S).

The first to third laser light sources 110 and 120 and 130 respectively emit laser light corresponding to the image to be generated. Here, the first laser light source 110 is composed of a first laser 111 for generating a red laser light, and a first current control device 112 for controlling the current supplied to the first laser 111, The second laser light source 120 is composed of a second laser 121 for generating a green laser light, and a second current control device 122 for controlling a current supplied to the second laser 121. The third laser light source 130 includes a third laser 131 for generating a blue laser light and a third current control device 132 for controlling a current supplied to the third laser 131.

Here, each of the lasers 111, 121, 131 provided in each of the laser light sources 110, 120, 130 is referred to as a vertically external cavity surface emitting laser (VECSEL). , Configuration as shown in FIG. These lasers 111, 121 and 131 have the same configuration except that only the kind of laser light generated by each of them is different. Therefore, hereinafter, only the configuration and operation of the first laser 111 illustrated in FIG. 3 will be described, and the second laser 121 and the third laser 131 will be replaced with the description of the first laser 111.

As shown in FIG. 3, the first laser 111 modulates a laser diode 113 for generating a laser light, a focusing lens 114 for focusing the emitted laser light at a predetermined position, and a frequency of the laser light. And an OPS chip 115 and a harmonic nonlinear optical member 116.

The first laser diode 113 receives a current to generate a laser light. The current supplied to the first laser diode 113 is controlled according to the gray scale of the image to be generated. That is, when bright light is required to implement an image, the first laser diode 113 receives a high current to emit a high power laser light, and conversely, when dark light is required, the first laser diode 113 ) Is applied with a low current to emit a low output laser light. The intensity of the current supplied to the first laser diode 113 is adjusted by the first current control device 112. When the image is completely dark, no current may be applied to the first laser diode 113.

The focusing lens 114 is composed of a plurality of lenses, and focuses the laser light emitted from the laser diode 113 and incident on the OPS chip 115.

The OPS chip (Optically Pumped Semiconductor) 115 modulates the frequency of the laser light emitted from the laser diode 113 and converts the laser light into a laser light having a frequency of a wide band, which is advantageous for a quick light output change. The OPS chip 115 may be a conventional one currently developed.

4 illustrates an OPS chip disclosed in US Pat. No. 6,370,168 as an example of a general OPS chip. As shown in FIG. 4, the OPS chip 115 includes a mirror layer 115a in which a plurality of mirrors are stacked, a gain region layer 115b in which a plurality of active layers are stacked, and selectively transmit or reflect incident light. The optical coating layer 115c is laminated in order. The heat sink 115d is coupled to the mirror layer 115a to assist in the generation of generated heat. The detailed configuration and operation of the OPS chip 115 other than this are already disclosed and thus will be omitted.

The harmonic nonlinear optical member 116 has a function of modulating the frequency of the laser light reflected from the OPS chip 115, and the red laser light completed while passing through the harmonic nonlinear optical member 116 is the exit lens 117. It is emitted through.                     

By the same configuration and operation as that of the first laser 111, the second laser 121 receives the green laser light corresponding to the gray scale of the image by receiving an appropriate current adjusted by the second current control device 122. The third laser 131 emits a blue laser light corresponding to the gray scale of the image by the third current controller 132 controlling the supply current.

The first to third optical filters 141, 142, and 143 are installed in the light exit paths of the laser light sources 110, 120, and 130, respectively, and the laser light sources 110, 120, and 130 respectively. The optical path of each laser beam is changed so that the red, green, and blue laser beams emitted from the same beam have the same emission path. The first optical filter 141 is a dichroic coating process to have a transmission or reflection characteristic according to the type of laser light, and is installed in the optical path of the red laser light. The first optical filter 141 transmits red laser light and reflects green and blue laser light. The second optical filter 142 is installed in the optical path of the green laser light so that the green laser light is reflected toward the first optical filter 141 and the blue laser light is transmitted. The third optical filter 143 reflects the blue laser light toward the first optical filter 141.

The polyhedral mirror 150 has a plurality of reflecting surfaces that reflect the laser light, and is installed in the same light exit path of the red, green, and blue laser light. The polyhedron mirror 150 scans the laser light in a horizontal direction of the screen while rotating at a high speed to implement a horizontal image on the screen (S).

The galvanometer mirror 160 is installed at a position following the multi-sided mirror 150 on the path of the laser light, and vibrates up and down to scan the laser light in the vertical direction of the screen S to screen the screen ( Implement vertical image in S).

Hereinafter, the operation of the laser scanning display device according to the present invention will be described.

When an image signal is applied from the outside, each current control device 112, 122, 132 controls the current supplied to each laser 111, 121, 131 according to the gray scale of each laser light for image realization. do. At this time, the first laser 111 applied with the current emits a red laser light having an output proportional to the supply current, and the second laser 121 emits a green laser light having an output proportional to the supplied current. The third laser 131 emits blue laser light having an output proportional to the current supplied thereto.

The red laser light emitted from the first laser 111 passes through the first optical filter 141 to the polyhedron mirror 150, and the green laser light emitted from the second laser 121 passes through the second optical filter ( After being reflected by 142, the light is reflected back by the first optical filter 141 and proceeds to the polyhedron mirror 150. The blue laser light emitted from the third laser 131 is reflected by the third optical filter 143, passes through the second optical filter 142, and is reflected by the first optical filter 141, and thus is half of the polyhedral mirror 150. The slope is reached.

The polyhedral mirror 150 rotates at a high speed and reflects each laser beam incident thereto to the mirror 170 in a horizontal direction within a predetermined angle range, and the laser beam reflected from the mirror 170 passes through the galvano mirror 160. In the vertical direction is scanned in the screen (S) a two-dimensional image is formed.                     

In the laser scanning display apparatus according to the present invention as described above, by controlling the current applied to each of the lasers 111, 121 and 131, the laser light of the output corresponding to the gray scale of the image to be represented is generated. Therefore, there is no need for a separate optical modulator for modulating the intensity of the emitted laser light.

In addition, by adopting a so-called vertically external cavity surface emitting laser (VECSEL) using an OPS chip, high-speed optical modulation is possible.

According to the present invention as described above, by controlling the current applied to the red, green and blue laser directly modulates the light output of the red, green and blue laser light corresponding to the gray scale of the image, waste and efficiency of the laser light The fall can be prevented. In addition, since there is no need for a separate optical modulator such as an acoustic-optic modulator (AOM) as in the related art, the configuration can be simplified and the size can be reduced.

In addition, according to the present invention, it is possible to increase the modulation speed of the laser light by using the OPS chip to implement a high-resolution laser scanning display device.

As mentioned above, although this invention was demonstrated through the preferable Example, this invention is not limited to the structure and operation as it was shown and described as such. That is, the present invention can be variously modified and changed within the spirit and scope of the claims described. Accordingly, all such suitable modifications and changes and equivalents should be considered to be within the scope of the present invention.

Claims (9)

A laser diode for generating laser light; An OPS chip that receives the laser light from the laser diode and reflects the laser light whose frequency is modulated; And And a current control device for controlling a current supplied to the laser diode so that the light output of the laser light emitted from the laser diode is changed. The method of claim 1, The current control device is a laser light source of the laser scanning display device, characterized in that for controlling the current according to the gray scale of the displayed image. The method of claim 1, And a harmonic nonlinear optical member which is installed on the optical path of the laser light reflected from the OPS chip and varies the frequency of the reflected laser light. The method according to claim 1 or 3, And a focusing lens provided between the laser diode and the OPS chip so that the laser light emitted from the laser diode is focused on the OPS chip. A first laser for generating a first laser light; A second laser for generating a second laser light; A third laser to generate a third laser light; A polyhedral mirror reflecting the laser light emitted from each of the lasers within a predetermined angle range and scanning in the horizontal direction of the screen; And a galvano mirror configured to scan the laser light in a vertical direction of the screen. Each of the lasers, A laser diode for generating laser light; An OPS chip that receives the laser light from the laser diode and reflects the laser light whose frequency is modulated; And And a current control device for controlling the current supplied to the laser diode so that the light output of the laser light emitted from the laser diode is changed. The method of claim 5, And the current control device controls the current according to the gray scale of the displayed image. The method of claim 5, And a harmonic nonlinear optical member installed on the optical path of the laser light reflected from the OPS chip to vary the frequency of the reflected laser light. The method according to claim 5 or 7, And a focusing lens installed between the laser diode and the OPS chip so that the laser light emitted from the laser diode is focused on the OPS chip. The method of claim 5, And an optical filter disposed in a light exit path of at least one laser light source of the plurality of laser light sources such that each laser light incident on the polyhedral mirror has the same incident light path.

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