KR20070079160A - Advanced contrast enhancer of video display device - Google Patents

Abstract

An advanced contrast enhancer of a video display device is provided to prevent impact with an internal wall of a projection lens when the advanced contrast enhancer for improving a contrast ratio is driven in a projection video display device. A movable part(50) adjusts a light quantity on an optical path provided to a projection lens in a projection video display device. A fixing part(60) rotates and drives the movable part(60) within a certain angle range. The movable part(50) is rotatably combined to the fixing part(60) by a shaft(70). A torsional spring(90) sets an initial position of the movable part(50). One end of the torsional spring(90) is fixed to the movable part(50) centering around the shaft(70), and the other end of the torsional spring(90) is fixed to the fixing part(60).

Description

ADVANCED CONTRAST ENHANCER OF VIDEO DISPLAY DEVICE}

1 is a diagram showing the structure of a projection image display apparatus using a transmissive LCD;

FIG. 2 is a diagram illustrating an example in which an advanced contrast enhancer is applied to a light engine of a DLP. FIG.

FIG. 3 is a diagram showing an example of applying an Advanced Contrast Enhancer to a light engine of LCos. FIG.

4 is a view showing the operating principle of the Advanced Contrast Enhancer as a device for improving the contrast ratio;

5 is a perspective view showing the structure of an Advanced Contrast Enhancer;

Figure 6 shows the internal structure of an Advanced Contrast Enhancer.

The present invention relates to an Advanced Contrast Enhancer, which is a device for improving contrast ratio in a projection video display device.

Recently, a video display device provides a thin, light and large screen. Such a large screen image display device is a projection TV. In a large-screen video display device, performance is required for not only the resolution but also factors that affect the viewing environment of viewers such as contrast ratio, brightness, and viewing angle.

In the case of contrast ratio, the higher the contrast ratio, the more distinct the screen and the more accurate the color can be expressed. Advanced Contrast Enhancer is applied as a device for improving the contrast ratio.

Advanced Contrast Enhancer is a technique to improve the contrast ratio by adjusting the amount of light similar to the aperture on the projected light path. Therefore, the Advanced Contrast Enhancer must be driven at an appropriate timing to improve the contrast ratio, and technical means for determining the initial position with stability in such mechanical / mechanical driving are required.

An object of the present invention is to provide a technical means for accurately determining an initial position when driving an advanced contrast enhancer for improving contrast ratio in a projection type image display apparatus.

Another object of the present invention is to provide a technical means that can prevent a collision with the inner wall of the projection lens when driving the Advanced Contrast Enhancer to improve the contrast ratio in the projection image display device.

An Advanced Contrast Enhancer of an image display device according to the present invention for achieving the above object is a movable part that is operated to adjust the amount of light on an optical path provided to a projection lens in a projection type image display device, and the movable part is predetermined. And a fixing unit for rotationally driving within an angle range, wherein the movable unit is rotatably coupled to the fixing unit by a shaft, and includes means for setting an initial position of the movable unit.

In the present invention, the initial positioning means is characterized in that the elastic means.

In the present invention, the initial positioning means is characterized in that the torsional spring (Torsional Spring).

In addition, in the present invention, the initial positioning means is a torsional spring (Torsional Spring) is fixed to the movable part, one end is fixed to the movable portion around the rotation axis.

In the present invention, the initial position setting means is characterized in that for setting the initial position of the movable portion to the optical path opening state.

In addition, the present invention, characterized in that it further comprises means for limiting the turning radius of the movable portion, along with the initial positioning of the movable portion.

In addition, in the present invention, in addition to the initial positioning of the movable portion, during the reciprocating rotational drive of the movable portion, the first stopper for limiting the radius of rotation for one end of rotation, and the second stopper for limiting the radius of rotation for the other end of rotation It is characterized by including.

In addition, in the present invention, together with the initial positioning of the movable portion, when the reciprocating rotational drive of the movable portion, a ring type first stopper for limiting the radius of rotation for one end of rotation and the rotation radius for the other end of rotation It further comprises a second stopper of the ring type (Ring Type) to limit.

In addition, the present invention, in addition to the initial positioning of the movable portion, further comprises a means for limiting the radius of rotation of the movable portion, characterized in that the collision between the movable portion and the projection lens inner wall by the rotation limiting means.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention.

In the present invention, the Advanced Contrast Enhancer inserts and drives a structure (plate) that adjusts the amount of light, such as an aperture, between a reflective or transmissive micro display device (MD) and a screen in a projection image display device. By adjusting the amount of light including the image information provided to the projection lens to improve the contrast ratio. Since the Advanced Contrast Enhancer is mechanically driven and uses a method of changing the amount of light, abnormal operation may be caused by internal or external factors that may occur during driving. Therefore, there is a need for effective technical means for securing stable operating characteristics when driving a device for improving contrast ratio.

In the present invention, a means for mechanically setting an initial position when driving an advanced contrast enhancer of the advanced contrast enhancer is applied, prevents collision with the inner wall of the projection lens when driving the movable part, and precisely limits the rotation radius to a prescribed value. By applying a stopper that can be used, the structural instability can be solved and the optical stability is secured accordingly.

First, the principle and structure of the projection type image display device and the advanced contrast enhancer will be described.

Fig. 1 shows an example of a projection image display device using a transmissive LCD (HTPS). Light emitted from the lamp 10 is uniformly illuminated on the transmissive LCD (HTPS) 13r, 13g, 13b of the R / G / B angle through the illumination system lens 11 and the reflector mirror (Dichroc Mirror, Mirror) 12. The light into which image information is input by a transmissive LCD (HTPS) is color synthesized by a prism (X-prism) 14, and the synthesized light is a device for improving contrast ratio 15 and a projection lens ( 16) to the screen. The Advanced Contrast Enhancer 15, which is a device for improving the contrast ratio, is inserted or attached to the light path in the projection lens 16 structure and improves the contrast ratio by adjusting the amount of light according to the analyzed screen information.

2 shows a projection optical system to which a contrast ratio enhancement device is applied in a light engine of the DLP. Like the system using the transmissive LCD, the contrast ratio enhancing device can be applied to achieve higher contrast ratio. That is, the light emitted from the lamp 20 enters the prism (TIR Prism) through the integrator 21, the color wheel 22, and the lens 23, and enters the DMD panel 25. The light inputted by the image information reaches the screen through the prism 24, the device for improving contrast ratio 26, and the projection lens 27.

3 shows a projection optical system using a device for improving contrast ratio in a light engine of a liquid crystal on sillicon (LCoS). Like the system using the transmissive LCD, the contrast ratio enhancing device can be applied to achieve higher contrast ratio. That is, the light emitted from the lamp 30 is imaged by the synthesis system 33 including the R / G / B polarized beam splitter (PBS) and the prism through the PSC 31, the dichroic mirror (mirror) 32, and the like. Information is input and synthesized, and the screen is reached through the contrast enhancing device 34 and the projection lens 35.

4 illustrates the structure and operating principle of the device for improving contrast ratio. As shown in the drawing, the device for improving the contrast ratio improves the contrast ratio by controlling the amount of light projected through the shutter plate 40 according to the screen information by opening and closing the light path like the aperture on the light path through which the light is transmitted. I have a principle to make. That is, the device structure for improving contrast ratio is in the shape of a light shielding film having an inner diameter equal to the radius of the projection lens light transmitting region, which is located in a path through which the image information formed as shown in FIG. 4 progresses, and the light shielding film-shutter plate 40 ) Is rotated at an appropriate angle in accordance with the contrast of the screen configuration information, and the contrast ratio is improved by adjusting the amount of projection light as the shutter plate 40 rotates in this way.

In FIG. 4, (a) shows the full light when the optical path is open (full opne) and the brightest screen, and (b) shows the half brightness of the optical path (half close) and the medium brightness screen. This is the case when the light path is almost closed (Full Close), which is the darkest screen.

5 is a perspective view showing the structure of an Advanced Contrast Enhancer.

In the projection image display apparatus, the movable part 50 is operated to adjust the amount of light on the optical path provided to the projection lens, and the fixing part 60 is configured to rotate the movable part within a predetermined angle range. The movable part 50 is coupled to the rotating shaft 70 so as to be rotatable to the fixed part 60.

The movable portion 50 is formed with a shaft coupling portion 51 for mounting the rotary shaft 70, the shutter plate 52 is attached to one side (upper side) as shown in the figure. The shutter plate 52 adjusts the amount of light on the projection light path. In order to adjust the amount of light, the shutter plate 52 has an inner diameter 43 that is the same as the radius of the projection lens light transmitting region, and a window 54 for ensuring minimum light transmission so that complete blocking of the projection light does not occur. Include. And the movable part 50 is provided with a coil 55 for driving the movable part on the other side (lower side) as shown in the figure. The coil 55 is an element for causing the movable part 50 to be driven to rotate based on the electromagnetic force between the magnet and the yoke installed in the fixing part 60, and is electrically connected by the cable 56.

6 is a diagram showing the internal structure of an Advanced Contrast Enhancer. As described above, the movable part 50 is rotatably coupled to the fixed part 60 by the rotation shaft 70, and the shutter plate 52 is positioned on the projection optical path above the movable part 50, and the movable part 50 is located above the movable part 50. Below, the driving coil 55 is provided. The driving coil 55 may be a winding coil or a fine pattern coil inserted into a PCB substrate. The fixing part 60 is provided with a magnet 61 and a yoke 62 for electromagnetically interacting with the coil 55. Here, the magnet 61 uses a two-pole magnet and is fixed to the fixing part 60 together with the yoke 62.

An advanced contrast enhancer consisting of the movable part 50 and the fixed part 60 is installed in the projection lens assembly 80 on the optical path.

When an electric signal is applied to the coil 55 through the cable 56 according to the screen analysis information, the movable part 50 is centered on the rotation axis 70 by the electromagnetic force between the coil 55 and the magnet 61-yoke 62. Rotates a predetermined angle, thereby improving the contrast ratio by adjusting the amount of light as described above with reference to FIG. 4 on the projection light path.

As described above, in adjusting the amount of light on the projection optical path by driving the Advanced Contrast Enhancer, the initial position of the movable part 50, that is, the initial position P_initial of the shutter plate 52 placed on the projection optical path is It is a very important factor. Since the initial position of the shutter plate 52 is based on an electrical signal when the movable unit 50 is driven later, when the initial position is incorrectly set, an error occurs in the rotation angle of the movable unit 50 in response to the drive signal. This error is because it is impossible to adequately control the amount of light, so that the contrast ratio improvement effect cannot be guaranteed.

In addition, when the movable part 50 rotates excessively during abnormal operation or transient response of the movable part 50, a collision with the inner wall of the projection lens may occur. In FIG. 6, the collision part 80 corresponds to a part where the shutter plate 52 is very likely to collide with the projection lens inner wall. Since the shutter plate 52 directly opens and closes the optical path, when the shutter plate 52 is subjected to a mechanical shock, fine alteration of the optical path and light amount due to vibration is induced, which leads to a deterioration of image quality, and also to a shutter. The possibility of deformation of the plate 52 is increased, resulting in poor durability, wear resistance, and mechanical stability.

In the present invention, a torsional spring 90 is applied as a means of limiting the radius of rotation of the advanced contrast enhancer. The torsion spring 90 was centered on the rotation shaft 70, one end 91 of which was fixed to the fixing part 60, and the other end 92 of which was fixed to the movable part 50. Using the fixed portion as a support point, the torsion spring 90 causes the movable part 50 to be placed at an initial position P_initial. This initial position was chosen as the position to fully open the light path.

Meanwhile, a stopper structure is applied as a means for limiting the rotation radius of the movable part 50. The stopper is provided with the first stopper 110 for one end of rotation and the second stopper 120 for the other end of rotation in the fixing part 60 in response to the movable part 50 being reciprocally rotated. By selecting the stoppers 110 and 120 as a ring type, it is possible to mechanically control the initial state and abnormal operation of the movable part 50 at the same angle even if the stopper 110 or 120 is inserted and fixed in any direction.

Therefore, when the movable part 50-the shutter plate 52 rotates clockwise as shown in the figure, the rotation radius is limited by the first stopper 110, and when the counterclockwise direction rotates, the second stopper The rotation radius is limited by 120. Here, the positions of the stoppers may be installed to restrict the rotation of the movable part 50 at the same angle from both the initial position P_initial, but may be installed corresponding to different rotation radii, adaptively to the characteristics of the device. In addition, since the rotation is limited by the contact between the movable part 50 and the stoppers 110 and 120, the material of the stopper is cushioned to minimize the impact caused by the collision between the stopper and the movable part during abnormal operation due to a transient response. It is preferable to select as.

Since the device for improving contrast ratio in the projection type image display apparatus according to the present invention can always maintain an accurate initial position, it is possible to secure mechanical and optical reliability in a driving operation for improving contrast ratio.

In addition, according to the present invention, because the projection lens inner wall and the shutter plate is prevented from colliding during abnormal operation or transient response of the movable part, noise generation due to collision is prevented, and damage to the projection light quantity control structure is improved, thereby improving durability and wear resistance. Can be.

In addition, in the present invention, by adopting a ring type stopper, the initial state and the normal operation of the movable part can be mechanically ensured regardless of the direction in which the stopper is inserted.

Claims (9)

In the projection-type image display apparatus, a movable part that is movable to adjust the amount of light on the optical path provided to the projection lens, and a fixing part for driving the movable part within a predetermined angle range, the movable part is rotated to the fixing part by the shaft And a means for setting an initial position of the movable portion, which is possibly coupled to the advanced display device. 2. The advanced contrast enhancer of claim 1, wherein the initial position setting means is an elastic means. 2. The advanced contrast enhancer of claim 1, wherein the initial positioning means is a torsional spring. The method according to claim 1, wherein the initial position setting means is a torsional spring fixed at one end to the movable part and the other end fixed to the fixed part about the rotating shaft. Enhancer. 2. The advanced contrast enhancer of claim 1, wherein the initial position setting means sets the initial position of the movable portion to the optical path opening state. 2. The advanced contrast enhancer of an image display apparatus as set forth in claim 1, further comprising means for limiting a rotation radius of the movable portion together with initial positioning of the movable portion. According to claim 1, In addition to the initial positioning of the movable portion, when the reciprocating rotation drive of the movable portion, the first stopper for limiting the radius of rotation for one end of rotation, and the second stopper for limiting the radius of rotation for the other end of rotation An advanced contrast enhancer of a video display device further comprising. The ring type first stopper for limiting the radius of rotation for one end of rotation and the rotation radius for the other end of rotation, together with the initial positioning of the movable part. An advanced contrast enhancer of a video display device, further comprising a ring type second stopper. The apparatus of claim 1, further comprising means for limiting a turning radius of the movable portion together with initial positioning of the movable portion, wherein the rotation limiting means prevents collision between the movable portion and the inner wall of the projection lens. Advanced contrast enhancer of video display apparatus to say.

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