JP2004029220A - Projection display device and liquid crystal panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection display device which reduces visual feeling of strangeness of a black display part projected on a screen, in the case a picture is displayed on a part of a display feasible region of a liquid crystal panel and the remaining part is allocated to black display. <P>SOLUTION: The liquid crystal panel is utilized to display a picture of the projection display device to project the picture on the screen by using light and is provided with a light shielding mask 50 to partition the picture display feasible region DR to display the picture to be projected on the screen. The light shielding mask 50 is provided with a gradation part 51 in which light transmittance gradually varies from an inner edge part 51a determining the picture display feasible region DR toward the outside. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a projection display device and a liquid crystal panel used for the same.
[0002]
[Prior art]
In a projection display device that projects an image displayed on a liquid crystal panel onto a screen using light from a light source, a light-shielding mask is arranged on an outer peripheral portion of the liquid crystal panel to restrict light from the light source from being incident. Things are known. Since various circuits and the like are present on the outer peripheral portion of the liquid crystal panel, these are prevented from being projected on a screen, and the operation is prevented from becoming unstable when light enters.
In the projection display device provided with the light-shielding mask, an area surrounded by the light-shielding mask is a displayable area of an image projected on the screen of the liquid crystal panel.
[0003]
[Problems to be solved by the invention]
By the way, in a projection display device provided with a light-shielding mask, for example, when the aspect ratio of the displayable area of the liquid crystal panel is 4: 3, the aspect ratio is 4 using the entire displayable area of the liquid crystal panel. : 3, an image IM having an aspect ratio of 4: 3 is projected on the screen Sc, for example, as shown in FIG.
On the other hand, when an image having an aspect ratio of 16: 9 is displayed on the liquid crystal panel, the upper and lower portions of the displayable area of the liquid crystal panel are displayed in black, and as shown in FIG. The image IM is projected on the screen Sc.
At this time, since the black display portion of the liquid crystal panel cannot completely block light, the black display region BR is displayed on the upper and lower portions of the image IM displayed on the screen Sc, and the black display region BR is displayed in gray. It becomes.
The outer edge Bd of the black display area BR corresponding to the inner edge of the light-shielding mask has a clear contrast, which may give a sense of incongruity when viewing the image IM.
[0004]
The present invention has been made in view of the above-described problems, and its purpose is to display an image on a part of a displayable area of a liquid crystal panel of a projection display device and to display the rest in black, It is an object of the present invention to provide a projection display device capable of reducing a sense of visual discomfort of a black display portion projected on a screen and a liquid crystal panel used for the projection display device.
[0005]
[Means for Solving the Problems]
The projection display device of the present invention is a projection display device that projects an image displayed on a liquid crystal panel on a screen using light from a light source, and an image is displayed on a part of an image displayable area of the liquid crystal panel. A gradation means for gradually changing the brightness of the outer edge of the black display area projected on the screen by the black display in a state where the remaining image displayable area is displayed in black.
[0006]
Preferably, the gradation unit has a light-shielding mask that partitions an image displayable area for displaying an image projected on the screen of the liquid crystal panel, and the light-shielding mask has an inner edge defining the image displayable area. And a gradation portion whose light transmittance gradually changes from the outside to the outside.
[0007]
The gradation means is arranged in an optical path between the light source and the screen, and a light-shielding member that defines an outer edge of a black display area projected on the screen by the black display, and is displayed on the liquid crystal panel. Moving means for moving the light-shielding member in accordance with the form of the image to be projected, wherein the light-shielding member has a light transmittance that gradually changes, and a brightness of an outer edge of a black display area projected on the screen. It is also possible to adopt a configuration having a gradation portion that gradually changes the length.
[0008]
The liquid crystal panel of the present invention is a liquid crystal panel used for displaying the image of a projection display device that projects an image on a screen using light, and has an image displayable area for displaying an image projected on the screen. The light-shielding mask includes a light-blocking mask, and the light-shielding mask includes a gradation portion in which light transmittance gradually changes from an inner edge defining the image displayable region to an outer edge.
[0009]
According to the present invention, when an image is projected on a screen in a state where an image is displayed in a part of the image displayable area on the liquid crystal panel and the remaining image is displayed in black, both the image on the liquid crystal panel and the black display are displayed on the screen. Is done. At this time, since the gradation means gradually changes the brightness of the outer edge of the black display area projected on the screen by the black display, the outer edge of the black display area is blurred, and the difference in contrast at the outer edge is reduced. Is done.
Further, the gradation means is realized by providing a gradation portion on a light-shielding mask that partitions an image displayable area for displaying an image projected on a screen in a liquid crystal panel.
Furthermore, independently of the light-shielding mask, a light-shielding member is arranged in an optical path between the light source and the screen, a gradation portion is provided on the light-shielding member, and the light-shielding member is moved according to the form of an image displayed on the liquid crystal panel. By doing so, the black display area on the screen is shaped according to the form of the image, and the outer edge is blurred, and the difference in contrast at the outer edge is reduced.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First Embodiment FIG. 1 is a diagram illustrating a schematic configuration of a projection display device according to an embodiment of the present invention.
The projection display apparatus 1 shown in FIG. 1 includes a light source 2, an integrator optical system 5, reflection mirrors 4, 9, 11, 12, a condenser lens 10, dichroic mirrors 6, 7, liquid crystal panels 20R, 20G, 20B, a polarizing plate. 21R, 21G, 21B, 22R, 22G, 22B, dichroic prism 30, projection optical system 25, and the like.
[0011]
The light source 2 includes a discharge lamp 2a and a reflection condenser mirror 2b. The light emitted from the discharge lamp 2a is condensed by the reflection condenser mirror 2b and emitted to the reflection mirror 4.
[0012]
The reflection mirror 4 reflects the illumination light L from the light source 2 toward the integrator optical system 5.
The integrator optical system 5 converts the illuminating light L from the light source 2 into illuminating light containing a large amount of S-polarized components and having a uniform polarization direction, and outputs the illuminating light.
The condenser lens 10 condenses the illumination light L that has passed through the integrator optical system 5 so that the illumination light L is superimposed on the liquid crystal panels 22R, 22G, and 22B.
[0013]
The dichroic mirror 6 is inclined by 45 degrees with respect to the optical axis of the illumination light L that has passed through the integrator optical system 5, and only the light LR in the red wavelength region of the illumination light L is reflected toward the reflection mirror 12, Light LGB in other wavelength ranges is transmitted.
[0014]
The reflection mirror 11 is inclined by 45 degrees with respect to the optical axis of the light LR reflected by the dichroic mirror 6, and reflects the light LR toward the liquid crystal panel 20R.
[0015]
The dichroic mirror 7 is inclined by 45 degrees with respect to the optical axis of the light LGB transmitted through the dichroic mirror 6, and directs only the light LG in the green wavelength range of the light LGB to the liquid crystal panel 20 </ b> G to integrator optical system 5. It is inclined at 45 degrees with respect to the optical axis of the passed illumination light L, and only the light LG in the green wavelength region of the illumination light L is reflected toward the liquid crystal panel 20G and transmits the light LB in other wavelength regions. .
[0016]
The reflection mirrors 9 and 11 reflect the light LB in the blue wavelength range toward the liquid crystal panel 20B.
[0017]
The liquid crystal panels 20 </ b> R, 20 </ b> G, and 20 </ b> B are respectively arranged at predetermined positions with respect to three side surfaces of the cubic dichroic prism 30.
Polarizers 21R, 21G, 21B as polarizers and polarizers 22R, 22G, 22B as analyzers are arranged in parallel on the incident side and the output side of the liquid crystal panels 20R, 20G, 20B, respectively.
[0018]
Each of the liquid crystal panels 20R, 20G, and 20B receives each light LR, LG, and LB entirely, and receives each light by a video signal corresponding to the three primary colors of red, green, and blue applied to the liquid crystal panels 20R, 20G, and 20B. Modulates the intensity of LR, LG, LB. The color lights LR, LG, LB having a predetermined polarization direction that have passed through the polarizing plates 21R, 21G, 21B undergo rotation of the polarization plane, in which the polarization plane is rotated, based on the video signal applied to the liquid crystal panels 20R, 20G, 20B. A predetermined polarization component of the transmitted light is transmitted through the polarizing plates 22R, 22G, and 22B, and is incident on the dichroic prism 30.
[0019]
The dichroic prism 30 is configured by joining a plurality of glass prisms, for example, and interference filters 30a and 30b having predetermined optical characteristics are formed on the joining surface of each glass prism.
The interference filter 30a reflects the blue light LB and transmits the red light LR and the green light LG. The interference filter 30b reflects the red light LR and transmits the green light LG and the blue light LB.
Therefore, the color lights LR, LG, LB modulated by the liquid crystal panels 20R, 20G, 20B are combined and enter the projection optical system 28.
[0020]
The projection optical system 25 projects, for example, the image light incident from the dichroic prism 30 toward the screen Sc. A color image is projected on the screen Sc.
[0021]
FIG. 2 is a plan view showing the structure of the liquid crystal panels 20R, 20G, and 20B, and FIG. 3 is a cross-sectional view taken along line AA of FIG. FIG. 2 is a plan view of the incident side of the liquid crystal panel 20.
As shown in FIG. 3, the liquid crystal panel 20 has an incident-side substrate 60, an emission-side substrate 61, and a liquid crystal 63.
The entrance side substrate 60 and the exit side substrate 61 are formed of, for example, a transparent glass substrate, and a closed space is formed between the entrance side substrate 60 and the exit side substrate 61 by the sealing member Sp. . The liquid crystal 63 is sealed in this closed space.
A transparent electrode and a TFT (Thin Film Transistor) element (not shown) are formed on the opposing surfaces of the incident side substrate 60 and the exit side substrate 61.
[0022]
A light shielding mask 50 is formed on the outer peripheral portion of the surface of the incident side substrate 60.
The light-shielding mask 50 blocks light from entering the incident-side substrate 60. Since various circuits are formed on the outer periphery of the liquid crystal panel 20, a light shielding mask 50 is provided to prevent light from entering these circuits.
The light shielding mask 50 is formed by depositing a metal film on the surface of the incident side substrate 60 or by printing.
[0023]
On the inner peripheral edge of the light-shielding mask 50, a gradation portion 51 is provided over the entire periphery. An area surrounded by the inner periphery of the gradation section 51 of the liquid crystal panel 20 is an image displayable area DR in which an image projected on the screen Sc can be displayed. That is, only the image displayed within the range of the image displayable area DR is projected on the screen Sc.
[0024]
FIG. 4 is a cross-sectional view for explaining the function of the gradation part 51 of the light-shielding mask 50.
As shown in FIG. 4, portions other than the gradation portion 51 of the light shielding mask 50 completely block the incident light L and do not allow the light L to enter the incident side substrate 60.
On the other hand, the gradation portion 51 has a relatively large transmittance near the inner peripheral edge 51a, and the transmittance of the light L gradually (continuously) decreases from the inner peripheral edge 51a toward the outer peripheral side of the light shielding mask 50. I do.
The gradation part 51 changes the thickness of the vapor deposition film gradually, for example, by forming the light shielding mask 50 with a metal vapor deposition film and gradually reducing the film thickness of the gradation part 51 toward the inner peripheral edge 51a. It can be formed by the following.
[0025]
Next, an operation when an image is projected on the screen Sc by the projection display device 1 having the above configuration will be described.
FIG. 5 is a diagram illustrating an example of an image display state of the liquid crystal panels 20R, 20G, and 20B.
In FIG. 5, the image IM does not use the entire area of the image displayable area DR surrounded by the light-shielding mask 50 of the liquid crystal panel 20 and is displayed in an area inside the image displayable area DR.
The entire outer peripheral area surrounding the image IM is a black display BL. The reason why the outer periphery of the image IM is the black display BL is to prevent light from transmitting from the periphery of the image IM.
[0026]
FIG. 6 is a diagram showing a state where the image IM shown in FIG. 5 is projected on the screen Sc.
The image IM of the liquid crystal panel 20 shown in FIG. 5 is projected as an image IMs on the screen Sc by each color light incident on the liquid crystal panel 20.
At this time, since the black display BL in the outer peripheral area of the image IM cannot completely block light, the light transmitted through the black display BL area of the liquid crystal panel 20 has a certain brightness on the screen Sc. The image is displayed as a black display area BLs.
The outer edge portion BLE of the black display region BLs is constituted by light transmitted through the gradation portion 51 of the light shielding mask 50 described above.
[0027]
With the gradation portion 51 having the above-described configuration, the brightness of the outer edge portion BLE of the black display region BLs gradually decreases toward the outside. For this reason, the outer edge portion BLE of the black display region BLs is in a blurred state, and a large contrast difference does not occur.
If the outer edge BLE of the black display area BLs is blurred, the outer edge BLE of the black display area BLs is inconspicuous when viewing the image IMs projected on the screen Sc, and does not become annoying to the viewer. improves.
[0028]
As described above, according to the present embodiment, the gradation portion 51 is formed on the inner peripheral edge of the light-shielding mask 50 provided on the outer peripheral portion of the liquid crystal panel 20, and the black display region BLs projected on the screen Sc by the gradation portion 51. Of the black display region BLs can be made inconspicuous.
[0029]
Second embodiment FIG. 7 is a diagram showing a schematic configuration of a projection display device according to another embodiment of the present invention.
The different configuration between the projection display device 100 shown in FIG. 7 and the projection display device 1 according to the above-described first embodiment is that the projection display device 100 has a light shielding plate 80R on the incident side of each of the liquid crystal panels 20R, 20G, and 20B. , 80G, and 80B. These light shielding plates 80R, 80G, 80B are movably supported by moving mechanisms 85R, 85G, 85B, respectively. The other configurations of the projection display device 100 and the projection display device 1 are the same.
[0030]
FIG. 8 is a plan view showing the relationship between the light shielding plates 80R, 80G, 80B and the liquid crystal panels 20R, 20G, 20B. FIG. 8 is a plan view of the incident side of the liquid crystal panel 20, and the polarizing plate is omitted.
As shown in FIG. 8, the light shielding plate 80 is disposed vertically above and below the liquid crystal panel 20, and is moved by the above-described moving mechanism 85 along the vertical direction of the screen of the liquid crystal panel 20.
[0031]
The light shielding plate 80 is obtained by forming a light shielding film on a transparent substrate such as a glass substrate by a method such as vapor deposition or printing.
The light-shielding plate 80 includes a light-shielding part 82 that completely blocks light and a gradation part 81 whose light transmittance gradually changes.
The gradation part 81 has the same function as the gradation part 51 in the above-described first embodiment, has the highest light transmittance near the end of the gradation part 81, and transmits light toward the light shielding part 82 side. The rate is decreasing gradually (continuously).
[0032]
A light-shielding mask 150 is provided on an outer peripheral portion of the incident side substrate of the liquid crystal panel 20. The inner peripheral edge 150a of the light-shielding mask 150 defines an image displayable area where an image projected on the screen Sc of the liquid crystal panel 20 can be displayed. The gradation part described in the first embodiment does not exist at the inner peripheral edge of the light-shielding mask 150, but a gradation part may be provided.
[0033]
When the image IM having the aspect ratio of 16: 9 as shown in FIG. 8 is displayed when the aspect ratio of the image displayable area DR of the liquid crystal panel 20 is, for example, 4: 3, the image IM of the image displayable area DR is displayed. Are black display BL.
When the light slightly transmitted from the black display BL is projected on the screen Sc, it occupies a considerably large area on the screen Sc. Further, the outer edge portion of the light slightly transmitted from the black display BL formed by the inner peripheral edge of the light shielding mask 150a is clearly projected on the screen Sc.
[0034]
For this reason, in the present embodiment, when the image IM as shown in FIG. 8 is displayed, as shown in FIG. 9, the gradation part 81 of the light shielding plate 80 is moved to near the upper and lower ends of the image IM. The movement of the light shielding plate 80 is performed by the moving mechanism 85 described above.
The light shielding plate 80 is positioned at a position where there is a certain margin with respect to the upper and lower ends of the image IM so that the end of the gradation portion 81 does not overlap the image IM. Therefore, the positioning accuracy of the moving mechanism 85 does not need to be so high.
[0035]
FIG. 10 is a diagram illustrating a state where the image IM of the liquid crystal panel 20 in the state illustrated in FIG. 9 is projected on the screen Sc.
As shown in FIG. 10, slightly above and below the image IMs projected on the screen Sc, a black display area BLs is formed by light transmitted through the black display BL in the outer peripheral area of the liquid crystal panel 20. Further, the outer edge portion BLE of the black display region BLs is blurred by the gradation portion 81 of the light shielding plate 80.
[0036]
As described above, according to the present embodiment, the incidence of light on the black display BL of the liquid crystal panel 20 is largely blocked by the light shielding plate 80, and the slight light transmitted through the black display BL is blocked by the light shielding plate 80. Since the gradation is projected by the gradation unit 81 onto the screen Sc, the black display area BLs hardly exists on the screen Sc, and the outer edge of the black display area BLs becomes inconspicuous.
[0037]
Third Embodiment In the above-described embodiment, the case has been described where the image IM displayed on the liquid crystal panel 20 is projected on the screen Sc as it is, but the projection display device and the screen Sc are inclined. If so, the display image will be distorted into a trapezoidal shape.
A technique is known in which the trapezoidal distortion is corrected into a correct shape by correcting the shape of the image IM displayed on the liquid crystal panel 20.
[0038]
For example, as shown in FIG. 11, the image IM displayed on the liquid crystal panel 20 is corrected to a trapezoidal shape opposite to the trapezoidal distortion generated on the screen Sc. At this time, black display BL is set on both sides of the image IM. Thereby, the image on the screen Sc is adjusted to a correct rectangular shape.
However, when the above-described correction is performed on the liquid crystal panel 20, the image IMs on the screen Sc is adjusted to a rectangular shape as shown in FIG. The upper black display area BLs is projected on both sides of the image IMs, which is annoying. Also, the overall shape of the image IMs and the black display area BLs is trapezoidal. Further, the outer edge portion of the black display region BLs has a large difference in contrast, and further causes a reduction in image quality of the screen Sc.
[0039]
In the projection display device according to the present embodiment, as shown in FIG. 13, a light shielding plate 180 capable of shielding the black display BL of the liquid crystal panel 20 is provided on the incident side of the liquid crystal panel 20.
The light shielding plate 180 is supported by a rotation mechanism 185 so as to be pivotable about a support shaft 186.
Further, a gradation portion 181 is formed at one end of the light shielding plate 180. The configurations of the light shielding plate 180 and the gradation portion 181 are the same as those of the above-described shielding plate 80 of the second embodiment.
[0040]
The light shielding plate 180 is normally arranged along the vertical direction, but when the image IM is trapezoidally corrected on the liquid crystal panel 20, the light shielding plate 180 is turned to the position shown in FIG. It is positioned at a position along the slope on both sides.
[0041]
FIG. 14 is a diagram illustrating a state where the image IM of the liquid crystal panel 20 in the state illustrated in FIG. 13 is projected on the screen Sc.
As shown in FIG. 14, on the left and right of the image IMs projected on the screen Sc, black display regions BLs formed by light transmitted through the left and right black displays BL of the trapezoidally corrected image IM of the liquid crystal panel 20 are projected. But the area is small. In addition, the entire outer shape of the image IM and the black display area BLs is rectangular and not trapezoidal, so that there is no sense of incongruity. Further, the outer edge portion BLE of the black display region BLs is blurred by the gradation portion 181 of the light shielding plate 180.
[0042]
As described above, according to the present embodiment, in addition to the same effects as those of the first and second embodiments described above, in addition to the black display area BLs projected on the screen Sc when the image IM is trapezoidally corrected. The shape of the entire image can be corrected to a rectangular shape.
[0043]
The invention is not limited to the embodiments described above.
In the embodiment described above, the projection type display device using a transmissive liquid crystal panel has been described, but the present invention is also applicable to a projection type display device using a reflection type liquid crystal panel. What is necessary is just to form a light shielding mask and a gradation part on the incident side substrate of the reflection type liquid crystal panel.
In the above-described embodiment, the case where the light-shielding mask is formed on the incident side substrate of the liquid crystal panel has been described. However, a light-shielding portion and a gradation portion are newly formed on a transparent substrate such as a glass substrate to constitute the light-shielding mask. Is also good.
Further, in the above-described embodiment, the light shielding plates 80 and 180 are arranged on the incident side of each liquid crystal panel 20, but, for example, a single light shielding plate is commonly arranged behind the condenser lens 10 or the like. Is also possible.
[0044]
【The invention's effect】
According to the present invention, when an image is displayed on a part of the displayable area of the liquid crystal panel of the projection display device and the remaining portion is displayed in black, the visual discomfort of the black display portion projected on the screen is reduced. Can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a projection display device according to an embodiment of the present invention.
FIG. 2 is a plan view showing the structure of the liquid crystal panels 20R, 20G, 20B.
FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2;
FIG. 4 is a cross-sectional view for explaining a function of a gradation portion 51 of the light-shielding mask 50.
FIG. 5 is a diagram illustrating an example of an image display state of the liquid crystal panels 20R, 20G, and 20B.
FIG. 6 is a diagram showing a state where the image IM shown in FIG. 5 is projected on a screen Sc.
FIG. 7 is a diagram showing a schematic configuration of a projection display device according to another embodiment of the present invention.
FIG. 8 is a plan view showing a relationship between light shielding plates 80R, 80G, 80B and liquid crystal panels 20R, 20G, 20B.
FIG. 9 is a diagram showing a state in which a gradation section 81 of the light shielding plate 80 has been moved to a position near the upper and lower ends of an image IM of the liquid crystal panel 20.
10 is a diagram illustrating a state where the image IM of the liquid crystal panel 20 in the state illustrated in FIG. 9 is projected on the screen Sc.
FIG. 11 is a diagram showing a state in which an image IM displayed on the liquid crystal panel 20 has been subjected to trapezoidal distortion correction.
FIG. 12 is a diagram showing a state in which an image IM of the liquid crystal panel 20 subjected to trapezoidal distortion correction is projected on a screen.
FIG. 13 is a view showing a relationship between a liquid crystal panel and a light shielding plate according to still another embodiment of the present invention.
14 is a view showing a state in which an image IM of the liquid crystal panel 20 in the state shown in FIG. 13 is projected on a screen Sc. FIG. 15 shows a display example of images of various sizes on a displayable area of the liquid crystal panel. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 100 ... Projection display apparatus, 2 ... Light source, 20 ... Liquid crystal panel, 50 ... Light shielding mask, 51 ... Gradation part, 60 ... Incident side substrate, 61 ... Outgoing side substrate, 63 ... Liquid crystal, 80, 180 ... Light shielding plate 81, 181: gradation section, 85: moving mechanism, Sc: screen, IM, IMs: image, BL: black display, BLE: black display area, DR: image displayable area.

Claims (4)

A projection display device that projects an image displayed on a liquid crystal panel onto a screen using light from a light source,
An image is displayed on a part of the image displayable area of the liquid crystal panel, and in a state where the rest of the image displayable area is black, the outer edge of the black display area projected on the screen by the black display is displayed. A projection display device having gradation means for gradually changing brightness. The gradation unit has a light-shielding mask that partitions an image displayable area that displays an image projected on the screen of the liquid crystal panel,
2. The projection display device according to claim 1, wherein the light-shielding mask includes a gradation portion whose light transmittance gradually changes from an inner edge defining the image displayable region to an outer edge. 3. The gradation unit is disposed in an optical path between the light source and the screen, and a light-blocking member that defines an outer edge of a black display area projected on the screen by the black display.
Moving means for moving the light shielding member according to the form of an image displayed on the liquid crystal panel,
2. The projection display device according to claim 1, wherein the light shielding member includes a gradation unit whose light transmittance gradually changes and gradually changes the brightness of an outer edge of a black display area projected on the screen. 3. . A liquid crystal panel used for displaying the image of a projection display device that projects an image on a screen using light,
A light-shielding mask that partitions an image displayable area that displays an image projected on the screen,
A liquid crystal panel, wherein the light-shielding mask includes a gradation portion in which light transmittance gradually changes from an inner edge defining the image displayable region to an outer edge.

Images