JPH05196888A - Front projection type display device - Google Patents

Abstract

PURPOSE:To suppress deterioration in picture quality and optionally set the projection position of a projected image without changing the position of a projection device main body. CONSTITUTION:The front projection type display device which enlarges and projects the object image 20 on a screen 18 by using a projection lens 16 is equipped with a projection lens moving mechanism 34 which varies the relative positions of the projected image 20 and projection lens 16 by moving at least one of the projected image 20 and projection lens 16 in a plane perpendicular to the optical axis 24 of the projection lens 16; and the relative positions of the projected image 20 and projection lens 16 are changed to shift the projected image 20 in the projection position on the screen 18, so the projected image 22 can be set at an optional position (e.g. position 22a shown by an alternate long and short dash line) on the screen 18 without changing the installation position of the projection device main body 32. The relative positions of the projected image 20 and projection lens 16 can be changed without slanting the projection device main body 3, so the deterioration in picture quality can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a front projection type display device in which a projection image is enlarged and projected on a screen by using a projection lens.

[0002]

2. Description of the Related Art As shown in FIG. 4, a front projection type display device using a general light valve screens projection light 12 from a light source 10 through a liquid crystal panel 14 as a light valve and a projection lens 16. The projected image 20 on the liquid crystal panel 14 is screened by illuminating the screen 18.
The image is projected on the screen 18 in an enlarged manner.

Then, the zoom mechanism of the projection lens 16 is utilized to enlarge or reduce the projection image 22 on the screen 18. In addition, the optical axis 24 of the projection lens 16 and the liquid crystal panel 1
By making the central axis 26 of the projected image 20 on the image No. 4 coincide with the image quality of the central portion of the projected image 22 on the screen 18, the balanced projected image 22 can be obtained. The central axis 26 of the projected image 20 coincides with the optical axis of the light source 10.

However, in the apparatus shown in FIG. 4, when the projected image 22 on the screen 18 has a large area, if the optical axis 24 of the projection system and the central axis 26 of the projected image 20 coincide with each other, the projected image is projected. Since the apparatus (projector) main body 28 must be set at the same high position as the center position of the screen 18, there is a problem that setting is difficult and there is a problem that the view of the viewer is obstructed.

In order to solve the above problems, in the conventional front projection display device, as shown in FIG. 5, the projected image 20 on the optical axis 24 of the projection lens 16 and the liquid crystal panel 14 is displayed.
The central axis 26 of the projector is fixed in the projector main body 30 in a state of being displaced by a predetermined distance, so that the projection is performed above the installation position of the projector main body 30 without setting the projector main body 30 at a high position. The large area projection image 22 can be projected on the screen 18.

[0006]

However, the conventional example shown in FIG. 5 has a problem that the projection position of the projection image 22 on the screen 18 cannot be arbitrarily set. Further, the projection position of the projection image 22 can be changed by tilting the projection device main bodies 28 and 30 and changing the tilt angle. However, the projection axis 22 of the projection lens 16 and the central axis 26 of the projected image 20 are not aligned with each other. There is a problem in that the projection surface of the lamp 18 is not perpendicular, and a keystone distortion (so-called trapezoidal distortion) appears, or the focus performance deteriorates due to a tilt angle.

The present invention has been made in view of the above problems, and a front projection display capable of arbitrarily setting the projection position of a projected image while suppressing the deterioration of image quality without changing the position of the projection apparatus main body. The purpose is to provide a device.

[0008]

SUMMARY OF THE INVENTION The present invention is a front projection display device in which a projection lens is used to magnify and project a projection image on a screen, and at least the projection image and the projection lens are provided. It is characterized by comprising a relative position changing mechanism for changing the relative position of the projected image and the projection lens by moving one of them in a plane perpendicular to the optical axis of the projection lens. .

[0009]

The relative position changing mechanism can change the relative position of the projection image and the projection lens by moving at least one of the projection image and the projection lens within a plane perpendicular to the optical axis of the projection lens. . As described above, changing the relative position of the projection image and the projection lens changes the position of the projection image on the screen.Therefore, you can change the projection image to any position on the screen without changing the installation position of the projector. Can be set to position. Moreover, the relative position of the projection image and the projection lens can be changed without tilting the projection apparatus main body.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the front projection type display device according to the present invention will be described below with reference to FIGS. 1, the same parts as those in FIGS. 4 and 5 are designated by the same reference numerals. In FIG. 1, 10 is a light source composed of a lamp and a reflector, 14 is a liquid crystal panel as a light valve, 16 is a projection lens, 1
Reference numeral 8 represents a screen.

The projection light 12 output from the light source 10 irradiates the screen 18 through the liquid crystal panel 14 and the projection lens 16 so that the projected image 20 on the liquid crystal panel 14 is projected onto the screen. The projection image 22 is enlarged and projected on the screen 18.
Reference numeral 24 represents the optical axis of the projection lens 16, reference numeral 26 represents the central axis of the projected image 20 on the liquid crystal panel 14,
Reference numeral 32 denotes the projection apparatus main body.

Reference numeral 34 is a projection lens moving mechanism provided in the projection apparatus main body 32.
Is configured to be able to move the projection lens 16 in the vertical direction indicated by an arrow 36 in a plane perpendicular to the optical axis 24. The projection lens moving mechanism 34 is specifically configured as shown in FIGS.

That is, the projection lens moving mechanism 34
Is a feed screw 38 pivotally supported by the housing 36,
A knob 40 for rotating the feed screw 38 and a guide portion (not shown) for holding the projection lens 16
And a projection lens holder 42 that is slidably provided in the vertical direction and is screwed into the feed screw 38.
By rotating the knob 40, the projection lens holder 42 can be moved in the vertical direction indicated by an arrow 44.

Next, the operation of the above embodiment will be described. When the knob 40 of the projection lens moving mechanism 34 is rotated, the projection lens holding body 42 moves in the vertical direction indicated by the arrow 44 in FIG. 2B, and the projection lens 16 also moves in the same direction. Now, when the projection lens holder 42 is in the position shown in FIG. 2B, the optical axis 24 of the projection lens 16 and the central axis of the projected image 20 on the liquid crystal panel 14 are shown by the solid line in FIG. Assuming that they coincide with 26, a projection image 22 shown by a solid line is projected on the screen 18. At this time, the optical axis of the projection light 12 and the central axis 26 of the projected image 20 are
Are provided in accordance with.

Next, when the knob 40 of the projection lens moving mechanism 34 is rotated in one direction to move the projection lens holder 42 upward in the vertical direction indicated by the arrow 44 in FIG. 2B, As shown by the alternate long and short dash line in FIG. 1, the projection lens 16 moves upward, and the relative position between the optical axis 24 of the projection lens 16 and the central axis 26 of the projected image 20 changes. Then, on the screen 18, the projected image 22 as shown by the dashed line
a is projected. That is, the projection position moves upward.

In the above-mentioned embodiment, for simplification of description, the case where the present invention is applied to the monochrome type front projection display device using one liquid crystal panel as a light valve has been described, but the present invention is not limited to this. It goes without saying that the present invention can also be applied to a color type front projection display device using three liquid crystal panels as light valves.

That is, as shown in FIG. 3, the projection light 12 from the light source 10 is converted to R by the dichroic mirrors 50 and 52.
(Red), G (green), B (blue) decomposed into three primary colors,
Then, the light is transmitted to the liquid crystal panels 14r, 14g and 14b as R, G and B light valves, and the dichroic mirrors 54 and 56 perform color combination, and the projection lens 16 screens them.
The projection lens 16 is configured to project on the screen, and the projection lens moving mechanism moves the projection lens 16 in the plane perpendicular to the optical axis of the projection lens 16 in the upward direction indicated by the one-dot chain line or in the downward direction indicated by the two-dot chain line. , The projection position of the projected image on the screen can be moved upward or downward. Numerals 58 and 60 are mirrors for changing the optical path to a predetermined direction.
Is.

In the above embodiment, the projection lens moving mechanism is
Although the projection lens is configured to move in the vertical direction in the plane perpendicular to the optical axis of the projection lens, the present invention is not limited to this, and the projection lens can be moved left and right in the plane perpendicular to the optical axis of the projection lens. It may be configured to move in a direction or an oblique direction.

In the above embodiment, the projection image from the light valve is screened by irradiating the screen with the projection light from the light source through the light valve and the projection lens.
The present invention is applied to the front projection display device for enlarging and projecting on the screen, but the present invention is not limited to this, and enlarging and projecting the projected image on the screen by using the projection lens. Any front projection display device can be used.

For example, the present invention can be applied to a front projection display device in which an image displayed on a CRT (cathode ray tube) is used as a projection image and the projection image is enlarged and projected on a screen by using a projection lens. can do.

In the above embodiment, the relative position variable mechanism is formed by the projection lens moving mechanism for moving the projection lens in the plane perpendicular to the optical axis of the projection lens, but the present invention is not limited to this. It suffices to move at least one of the projection image and the projection lens within a plane perpendicular to the optical axis of the projection lens.

For example, the relative position variable mechanism may be formed by a projected image moving mechanism that moves the projected image in a plane perpendicular to the optical axis of the projection lens while keeping the position of the projection lens unchanged. Specifically, in the case of a projection device that uses a CRT, by devising a deflection circuit, CR
Since the display area of the T display screen can be moved vertically and horizontally, the projection screen on the screen is moved by moving the display area of the CRT display screen.

In the case of a projection device using a liquid crystal panel, a slightly smaller projected image area is set in the displayable image display area of the liquid crystal panel, and an image that can display this projected image area is set. The projection screen on the screen is moved by moving within the display area. In this case, if a liquid crystal panel having a sufficient number of pixels for a video signal appears, a projected image with higher display quality can be obtained.

[0024]

As described above, the front projection display apparatus according to the present invention projects the projected image by moving at least one of the projected image and the projection lens in a plane perpendicular to the optical axis of the projection lens. It is equipped with a relative position variable mechanism that changes the relative position of the lens.By changing the relative position mechanism, the position of the projected image on the screen can be changed. Instead, the projected image can be set at any position on the screen. Moreover, since it is not necessary to tilt the projection apparatus main body, it is possible to suppress deterioration of the projected image on the screen.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a front projection display device according to the present invention.

2A and 2B show a specific example of the projection lens moving mechanism of FIG. 1, in which FIG. 2A is a front view and FIG. 2B is a sectional view taken along line AA of FIG.

FIG. 3 is an explanatory diagram illustrating another embodiment.

FIG. 4 is a schematic configuration diagram showing a conventional example.

FIG. 5 is a schematic configuration diagram showing a conventional example.

[Explanation of symbols]

10 ... Light source, 12 ... Projection light, 14 ... Liquid crystal panel (an example of light valve), 16 ... Projection lens, 18 ... Screen, 20 ... Projected image, 22, 22a ... Projection image, 24 ... Projection lens 16 Optical axis, 26 ... central axis of projected image 20, 28, 30, 32 ... Projector main body, 3
4 ... Projection lens moving mechanism (an example of a relative position changing mechanism).

Claims (3)

[Claims] 1. A screen for projecting a screen using a projection lens.
In a front-projection display device configured to magnify and project on the projection image, the projection image and the projection image are moved by moving at least one of the projection image and the projection lens in a plane perpendicular to the optical axis of the projection lens. A front projection display device comprising a relative position changing mechanism for changing the relative position of a projection lens. 2. The front projection display device according to claim 1, wherein the relative position variable mechanism is a projection lens moving mechanism that moves the projection lens in a vertical direction in a plane perpendicular to the optical axis of the projection lens. 3. The front projection display device according to claim 1, wherein the relative position variable mechanism is a projected image moving mechanism for moving the projected image in a vertical direction within a plane perpendicular to the optical axis of the projection lens.