KR100813729B1 - Method and apparatus for controlling of a projection type image display device - Google Patents

Abstract

The present invention is to improve the contrast and image quality of the image projected on the screen in the optical system of the projection image display device.

That is, the present invention is a projection type having a lamp, a color wheel that the white light emitted from the lamp rotates at a predetermined rotation frequency, a prism, and a DMD element for adjusting the angle of the light incident on the total reflection inside the prism In the image display device, a DMD driver for outputting the on, off and flat command of the DMD element, and the switching state of the DMD element according to the command input through the DMD driver is determined and emitted through the lamp It comprises a transmission control unit for selectively blocking the light.

Therefore, the control apparatus and method of the projection image display device according to the present invention does not deteriorate the dark state by selectively blocking the light according to the switching state of the DMD element by using an element capable of selectively transmitting light. It can be prevented, and by operating in accordance with the response speed of the DMD element can minimize the transient phenomenon appearing while the DMD element responds to the signal, thereby improving the image quality and the contrast can be improved.

DMD / optical

Description

Method and apparatus for controlling of (a) projection type image display device}

1 is a view schematically showing a projection image display device according to the prior art.

2 is a view showing an optical path of a projection type image display device according to the prior art.

3 is a flowchart illustrating a control method of a projection image display device according to the related art.

4 is a view showing a control device of a projection image display device according to the present invention;

5 is a flowchart illustrating a control method of a projection image display device according to the present invention;

<Description of Symbols for Major Parts of Drawings>

100: lamp 120: color wheel

140: prism 150: micro mirror

160: DMD element 170: transmission control

180: DMD drive unit 200: screen

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device, and more particularly, to an apparatus and method for controlling a projection type image display device to improve contrast and image quality of an image projected on a screen in an optical system of a projection type display device.

In recent years, with the development of the information industry, the demand for image display apparatuses capable of displaying large screen images is increasing. Projection image display apparatuses, which can display large-sized images, are included. Digital light processing (DLP) projectors using digital micromirror device (DMD) devices have recently been in the spotlight.

The DMD device is exclusively developed by Texas Instruments, Inc., and has about 1.3 million micromirrors integrated therein, and the micromirror reflects light incident from the outside in response to individual digital control signals to the screen. Implement the image.

Hereinafter, a projection image display device according to the related art will be described with reference to the accompanying drawings.

1 is a block diagram schematically showing the configuration of a projection image display device according to the prior art, Figure 2 is a view showing the light path of the projection image display device according to the prior art, Figure 3 is a projection image display according to the prior art It is a flow chart which shows the control method of a device.

In the projection type image display device according to the related art, as shown in FIG. 1, the white light emitted from the lamp 10 is converted into R, G, and B light in time by a color wheel rotating at a predetermined rotation frequency. Separated and incident on the prism 14. At this time, the incident light is totally reflected in the prism 14 and is incident on the plurality of micromirrors 15 provided in the DMD element 16. In addition, the incident light is reflected on the projection lens 20 according to the inclination angle of the micromirror 15 and displayed on the screen 22 or is projected into a light absorber (not shown) or in the air.

The angles of the plurality of micromirrors 15 are controlled according to on, off and flat signals input from the DMD driver 18, which determines the propagation angle of the reflected light. For example, the micromirror 15 is inclined 12 ° (+ 12 °) to the left side when the on-signal signal is inclined, and is inclined to 12 ° (-12 °) to the right side when the off-signal signal is inclined. ). Here, the reason why the flat signal is required is that the DMD element 16 needs to be refreshed every predetermined period in order to maintain the normal operation. In this refresh operation, all the micromirrors 15 in the DMD element 16 are refreshed. ) Will be kept horizontal (0 °).

When the micromirror 15 is in the on state, the reflected light is projected onto the screen through the projection lens 20, and the reflected light in the off state and the flat state is projected into the light absorber or air and is not projected onto the screen.

The prism 14 of the projection image display device according to the prior art includes a first prism 14a having a total reflection surface 14c for totally reflecting light incident through the color wheel 12 in the direction of the micromirror 15, It consists of the 2nd prism 14b arrange | positioned in contact with the said total reflection surface 14c.

Here, a minute gap d, or an air gap, is formed between the first prism 14a and the second prism 14b, and the total reflection reflects the refractive index of the first prism 14a and the gap. Occurs due to a difference.

Hereinafter, the light paths will be described in more detail with reference to the accompanying drawings when the DMD device is in an on, off, and flat state.

First, FIG. 2 (a) shows a path of light when the DMD device is in an on state. The micromirror 15 is inclined + 12 °, and the light that is totally reflected by the first prism 14a is incident to the light path. After being reflected back from the micromirror 15, it is emitted into a light absorber (not shown) or air.

In addition, when the DMD element is in the off state, the light path is as shown in FIG. 2B, and the micromirror 15 is tilted at −12 °, and the light is totally reflected by the first prism 14a and is incident. Is reflected back from the micromirror 15 and then emitted into the light absorber (not shown) or in the air. In this case, since there is no light emitted through the projection lens 20, a black image is displayed on the screen.

In addition, when the DMD element is in a flat state, the path of light is as shown in FIG. 2C, and the micromirror 15 is in a horizontal (0 °) state and the first prism 14a. Some of the light 50 totally reflected from the incident light is reflected back from the micromirror 15 and then emitted to a light absorber (not shown) or to the air, but the other part 51 is emitted to the projection lens 20. Projected on the screen.

When the DMD element is in a flat state, a black screen should be displayed on the screen. However, as shown in FIG. 2C, some of the light reflected from the micromirror 15 is projected by the projection lens. It is projected to the screen through 20) to make the black screen brighter, but this causes the contrast of the image to be lowered.

The control method of the projection type image display device according to the related art configured as described above will first be described with reference to FIG. 3.

When the video signal is input, light of each pixel is adjusted (S13).

Subsequently, the pixel state of the DMD device is determined (S14). At this time, the on, off and flat state of the DMD device is determined.

The screen is output according to the state of the set DMD element (S15).

Finally, when the user inputs the power off command, the process ends (S16).

In addition, in order to prevent the phenomenon in which the light energy is continuously irradiated to the mirror of the DMD element destroys the hinge supporting the DMD element, a section is always required to be reset to the flat state. In addition, to maintain a constant time to move to the state (on / off) to be displayed in the next signal section of the DMD element should be in a flat state (Flat).

During this period, undesired light is reflected toward the projection lens, and the DMD element in the off state is reflected inside the light tube, resulting in diffuse reflection. These reflections reduce the quality of the image and cause problems such as lifting in the dark state.

The present invention has been made to solve the above problems, and it is possible to avoid the floating state of the dark state caused by the diffuse reflection of the light and the unwanted light incident when the DMD device is switched on, off, and flat state. Its purpose is to prevent it.

The present invention has another object to improve the contrast of the projected image signal.

In addition, the present invention has another object to improve the image quality of the video signal.

The present invention has been made to achieve the above object, the control device of the projection image display device according to the present invention is a lamp, the white light emitted from the lamp rotates at a predetermined rotation frequency (Color Wheel), prism And a DMD driver for outputting an on, off, and flat command of the DMD element in the projection type image display device including a DMD element for adjusting an angle of light incident to total reflection in the prism. It is characterized by including a transmission control unit for selectively blocking the light emitted through the lamp by determining the switching state of the DMD element according to the command input through.

Preferably, the transmission control unit has a characteristic of blocking light emitted through the lamp when a command to be switched from the on state to the off state is input through the DMD driver.

More preferably, the transmission control unit blocks the light emitted through the lamp when the command inputted through the DMD driver is turned on in a flat state.

More preferably, the transmission control part includes an ultraviolet blocking layer, first and second electrodes, glass support partition walls formed at regular intervals between the first and second electrodes, and an aqueous solution and an organic solution filled between the glass support partition walls. And an insulating layer formed on the second electrode.

More preferably, the organic solution is agglomerated on one side of the glass support bulkhead in order to pass light emitted through the lamp according to a command input through the DMD driver, and to block light emitted through the lamp. It is characterized by being spread to both ends of the support bulkhead and the glass support bulkhead.

A control method of a projection image display device according to the present invention for achieving the above object is a lamp, the white light emitted from the lamp is totally reflected in the color wheel (prism), the prism, the prism to be rotated at a predetermined rotation frequency incident A control method of a projection image display device having a DMD element for adjusting an angle of light to be provided, the method comprising: determining a pixel state of the DMD element when an image signal is input, and switching state according to the determined pixel state of the DMD element And determining to selectively block the light emitted from the lamp according to the switching state.

More preferably, the step of determining the pixel state of the DMD element is a step of determining the on, off and flat state of the DMD element according to the input image signal.

More preferably, the determining of the switching state according to the pixel state of the DMD element may include whether the state of the DMD element is switched from an on state to an off state, whether the state of the DMD element is switched from an on state to a flat state, or the DMD. Whether the state of the device transitions from the off state to the on state, whether the state of the DMD element transitions from the off state to the flat state, whether the state of the DMD element transitions from the flat state to the on state, or the state of the DMD element is flat It is the step of judging whether the state goes from the off state.

More preferably, selectively blocking the light emitted from the lamp is characterized in that the light emitted from the lamp is blocked when the DMD element is switched from the on state to the off or flat state.

Hereinafter, a control apparatus and a method of a projection image display device according to the present invention will be described in detail with reference to the accompanying drawings.

4 is a block diagram illustrating a control apparatus of a projection image display apparatus according to the present invention, FIG. 5 is a flowchart illustrating a control method of the projection image display apparatus according to the present invention, and FIG. 6 is a transmission control unit shown in FIG. Figure in detail.

As shown in FIG. 4, the control apparatus of the projection image display device according to the present invention includes a DMD driver 180 for outputting on, off, and flat commands of the DMD element 160, and the DMD driver 180. And a transmission control unit 170 for selectively blocking the light emitted through the lamp 100 by determining the switching state of the DMD element 160 according to the command input through the control panel.

That is, the white light emitted from the lamp 100 is separated into R, G, and B light in time by the color wheel 120 rotating at a predetermined rotation frequency and is incident to the prism 140. At this time, the incident light is totally reflected in the prism 140 and is incident on the plurality of micromirrors 150 provided in the DMD element 160. In addition, the incident light is reflected by the projection lens 200 according to the inclination angle of the micromirror 150 and displayed on the screen 122, or is projected into a light absorber (not shown) or in the air.

The angles of the plurality of micromirrors 150 are controlled according to on, off, and flat signals input from the DMD driver 180, which determines the propagation angle of reflected light. For example, the micromirror 15 is inclined 12 ° (+ 12 °) to the left side when the on-signal signal is inclined, and is inclined to 12 ° (-12 °) to the right side when the off-signal signal is inclined. ). Here, the reason why the flat signal is required is that the DMD element 16 should be refreshed every predetermined period in order to maintain a normal operation. During this refresh operation, all the micromirrors 150 in the DMD element 160 are refreshed. ) Will be kept horizontal (0 °).

When the micromirror 150 is in the on state, the reflected light is projected onto the screen through the projection lens 120, and the reflected light in the off state and the flat state is projected into the light absorber or air and is not projected onto the screen.

In this case, the transmission control unit 170 determines whether the command input through the DMD driver 180 is one of the on, off, and flat commands of the DMD element 160, and at this time, the switching operation according to the command input is turned on. Determine whether it is off or flat in the state.

That is, when the command input through the DMD driver 180 is the OFF command or the flat command when the DMD element 160 is on, the light emitted through the lamp 100 is not projected onto the screen 120. Block it.

As shown in FIG. 6A, the transmission control unit 170 includes an ultraviolet (UV) blocking layer 171, a first electrode 171 formed under the ultraviolet blocking layer 171, and the A second electrode 174 formed at a predetermined interval on the first electrode 172, a glass support partition wall 173 formed at a predetermined interval between the first electrode 171 and the second electrode 174, and The insulating layer 175 is formed below the second electrode, and the aqueous solution 177 and the organic solution 176 are introduced between the glass support partition wall 173.

That is, when an on-off or on-flat command is input through the DMD driver 180, the organic solution 176 spreads to the bottom of the second electrode as shown in FIG. When a command other than the on-off or on-flat command is inputted, as shown in FIG. 6 (b), the organic solution 176 is bound to one side of the glass support partition wall 173. As a result, light passes through the portion where the organic solution 176 does not aggregate.

Therefore, when no voltage is applied between the first electrode 172 and the second electrode 174, the organic solution 176 is agglomerated out of the transmission layer due to the surface tension as shown in FIG. When the light is transmitted, when the voltage is applied, as shown in FIG. 6 (a), the organic solution 176 spreads widely, thereby causing an electrowetting phenomenon that blocks light from being transmitted. .

The control method of the projection image display device according to the present invention configured as described above will be described with reference to FIG. 5. First, when a user inputs a power on command, an image signal is input (S101 to S102).

When the video signal is input, the pixel of the DMD device is adjusted (S103).

In operation S104, the pixel state of the DMD element is determined. At this time, the on, off and flat state of the DMD element is determined.

Subsequently, it is determined whether the determined state is selected as the flat state or the off state (S105).

As a result of the determination (S105), if a flat or off state is selected in the on state, light transmission is blocked (S106).

On the other hand, if the determination result (S105), the flat state or the off state is not selected in the on state, the screen is output while controlling the DMD element according to a preset state (S107).

When the user inputs the power off command, the process ends (S108).

As described above, in the control apparatus and method of the projection image display device according to the present invention, the DMD element is switched according to the input image, and the switching state of the DMD element is determined to be switched from the on state to the off or flat state. When using the transmission control unit to block the light.

As described above, the control device and method of the projection image display device according to the present invention have the following effects.

First, it is possible to prevent the dark state from deteriorating by selectively blocking the light according to the switching state of the DMD element by using an element capable of selectively transmitting light.

Second, by operating at the response speed of the DMD device it is possible to minimize the transient that appears while the DMD device responds to the signal.

Third, the image quality can be improved and the contrast can be improved by preventing the diffuse reflection of light and the incidence of unwanted light.

Claims (9)

In a projection type image display device having a lamp, a color wheel (rotation of white light emitted from the lamp is rotated at a predetermined rotation frequency), a prism, a DMD element for adjusting the angle of the light incident totally reflected in the prism, A DMD driver for outputting on, off, and flat commands of the DMD element; And, And a transmission control unit for selectively blocking the light emitted through the lamp by determining a switching state of the DMD element according to a command input through the DMD driver. The method of claim 1, The transmission control unit And a light output through the lamp is blocked when a command to be switched from the on state to the off state is inputted through the DMD driver. The method of claim 1, The transmission control unit The control apparatus of the projection image display device, characterized in that to block the light emitted through the lamp when a command to switch to the flat state from the command input through the DMD driver. The method of claim 1, The transmission control unit An ultraviolet blocking layer, first and second electrodes, glass support partition walls formed at regular intervals between the first and second electrodes, an aqueous solution and an organic solution filled between the glass support partition walls, and an upper portion of the second electrode Control device of a projection type image display device, characterized in that consisting of an insulating layer formed on. The method of claim 4, wherein The organic solution is agglomerated on one side of the glass support bulkhead in order to pass the light emitted through the lamp according to a command input through the DMD driving unit, and the glass support bulkhead and the glass support bulkhead to block the light emitted through the lamp. Control device of a projection-type video display device characterized in that it is formed to spread across the glass support partition wall. Control of a projection type image display device having a lamp, a color wheel rotating white light emitted from the lamp at a predetermined rotation frequency, a prism, and a DMD element for adjusting the angle of light incident on the total reflection inside the prism. In the method, Determining a pixel state of the DMD element when an image signal is input; Determining a switching state according to the determined pixel state of the DMD element; And, And selectively blocking the light emitted from the lamp according to the switching state. The method of claim 6, Determining the pixel state of the DMD device And determining on, off and flat states of the DMD element according to the input image signal. The method of claim 6, The determining of the switching state according to the pixel state of the DMD element Whether the state of the DMD element is switched from an on state to an off state, the state of the DMD element is switched from an on state to a flat state, the state of the DMD element is switched from an off state to an on state, or the state of the DMD element Is determined whether is switched from the off state to the flat state, whether the state of the DMD element is switched from the flat state to the on state, or whether the state of the DMD element is switched from the flat state to the off state. Control method of equipment. The method of claim 6, Selectively blocking the light emitted from the lamp And controlling the light emitted from the lamp to be blocked when the DMD element is switched from the on state to the off state or the flat state.

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