JPH10319499A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute highly accurate lens shifting by a simple structure and also to close the aperture part of a front surface panel. SOLUTION: A projection lens 18 is provided at the aperture part 13 of the front surface panel 12, and light radiated from a light source means 15 forms a projection image plane by enlarging and projecting transmitted light through a liquid crystal panel 14 as a projection object. A lens board 19 covers the aperture part 13 of the front surface panel 12 in a state that the projection lens 18 is attached, and a rotary shaft 22 is provided at a position offset by a specified quantity from the optical axis 21 of the projection lens 18, and the lens board 19 is rotated by centering the rotary shaft 22, so that the projection lens 18 is moved in circular-arc shape and is moved in a shifting direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector for projecting image light on a projection target to display an image.

[0002]

2. Description of the Related Art Heretofore, there has been provided a projection-type projector device capable of magnifying and projecting an image of a personal computer screen or a video device and presenting the image to a large audience. As such a projection type projector device, a so-called liquid crystal projector using liquid crystal for a display element and incorporating a projection light source means has been widely used in recent years.

In a liquid crystal projector, the resolution of an image is determined by the number of pixels of a liquid crystal element. Here, since the number of pixels of the liquid crystal element is limited, the liquid crystal projector usually utilizes the display area of the liquid crystal as effectively as possible. For this reason, the display area of the liquid crystal often has almost the same aspect ratio as the conventional cathode ray tube, and ordinary liquid crystal projectors project a horizontally long image, which is suitable for the projection of personal computers and video screens described above. Can be anything. On the other hand, most liquid crystal projectors have a fixed projection lens position, a configuration in which the projection lens is shifted upward by a fixed amount with respect to the liquid crystal, and projecting an image obliquely upward, the screen can be displayed in a normal position. It is easy to see. This is generally called a tilt projection method. If you want to move the image further up,
This is possible by extending the front height adjustment foot and shifting the projection direction upward, but at this time, the angle formed by the screen and the liquid crystal changes, and the image is distorted into a trapezoid. In order to solve this problem, there is a camera in which the optical axis of the lens is perpendicular to the screen and the lens is moved up, down, left, and right to adjust the positional relationship between the screen and the liquid crystal projector.

On the other hand, a conventional overhead projector (hereinafter, referred to as an OHP) has a substantially square projection area. When a document to be projected is rectangular, the document can be placed in either portrait or landscape orientation. Easy to use.

[0005] On the other hand, a document camera apparatus has already been provided which shoots a document or other object with a video camera and outputs the image to a large projector or a small monitor. When photographing a vertically long document using this apparatus, the angle of view of the photographing lens may be changed to a wide angle.

On the other hand, in a case where an image is not square, and is projected on a horizontally long rectangular image such as a television monitor, when the original is horizontally long, even if the entire area is photographed, the margin is small and the enlargement ratio is large. There is no problem because it can be done, but when the original is vertically long, the enlargement ratio becomes small in whole-area shooting, and it becomes difficult to distinguish characters. That is, a portrait image is desirable for projecting a portrait document.

[0007] However, there is no suitable method for projecting a vertically long image using a conventional device other than turning the small monitor sideways, and there is no method for providing it to many audiences at once.

If a normal liquid crystal projector is turned over, a vertically long screen can be projected, but this has the following problems.

That is, in many small-sized liquid crystal projectors, the position of the lens is fixed, and an ordinary vertically long screen is projected obliquely upward to make it easier to see the screen. Because the screen is projected to the right or left, for example, when placed on a table, the bottom of the vertical screen will be below the table,
The screen is hard to see. To solve this problem, a liquid crystal projector to which the above-described lens shift mechanism is added has been developed.

FIG. 10 is a perspective view showing such a conventional liquid crystal projector.

In FIG. 10, reference numeral 90 denotes a liquid crystal projector main body. A projection lens 93 is provided through a first and second shift portions 94 and 95 at an opening 92 on the right side of a front panel 91 of the liquid crystal projector main body 90. Attached. The first shift unit 94 holds the second shift unit 95 in a state where it can be shifted up and down. The second shift unit 95 holds the projection lens 93 in a state where the projection lens 93 can be shifted left and right.

The first and second shift units 94 and 95 include:
The bellows portions 96 and 97 are provided to prevent light leakage and dust from entering through the opening portion 92.

In such a conventional liquid crystal projector,
The first and second shift units 94 and 95 are mechanisms for moving the vertical projection lens 93 vertically and horizontally while accurately holding the heavy projection lens 93, and it is necessary to keep the positional accuracy within a certain allowable limit. Had become. In addition, a wide opening is required in the front panel to secure a space for the projection lens 93 to move in advance, and a slide cover and a bellows portion are required to prevent light leakage and dust from entering therefrom. And increased costs.

FIG. 11 is an explanatory view showing another problem of the liquid crystal projector of FIG.

The projection lens 9 of the liquid crystal projector shown in FIG.
As a mechanism for moving the lens 3, there are a manual type and an electric type by a motor or the like. In the case of the electric type, as shown in FIG.
In order to prevent injuries even if the hand 98 is accidentally pinched between the rims, an operation force limiting mechanism and a finger pinch detecting means are required, which causes an increase in cost.

[0016]

In the above-mentioned conventional liquid crystal projector, a mechanism for moving a heavy projection lens vertically and horizontally while maintaining it accurately causes an increase in weight and cost, and furthermore, a space in which the projection lens moves. The front panel needs a wide opening to secure in advance, and a slide cover and bellows are required to prevent light leakage from this and the intrusion of dust, leading to an increase in cost. Was. In addition, when an electric type is used as a mechanism for moving the projection lens, an operation force limiting mechanism and a finger pinch detection unit are required, which causes an increase in cost.

An object of the present invention is to provide a liquid crystal projector capable of performing a highly accurate lens shift with a simple structure and closing an opening of a front panel.

[0018]

According to a first aspect of the present invention, there is provided a liquid crystal projector including a main body case having an opening formed in a front panel, and a liquid crystal panel housed in the main body case and having a display surface including a plurality of pixels. And light source means housed in the main body case and irradiating the liquid crystal panel with light, light provided from an opening of the front panel, and light emitted from the light source means transmitted through the liquid crystal panel, or A projection lens that forms a projection screen by enlarging and projecting the light reflected by the liquid crystal panel onto a projection target, and closing an opening of the front panel with the projection lens attached, and an optical axis of the projection lens. A rotation axis is provided at a position offset by a fixed amount from the lens board, and the projection lens is moved in the shift direction by rotating about the rotation axis, and a lens board, Characterized by comprising.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the first invention of the liquid crystal projector according to the present invention, and shows a case where projection is performed in a horizontal position. The liquid crystal projector may be of a single-panel type, a three-panel type, or the like depending on the number of liquid crystals to be used.

In FIG. 1, reference numeral 11 denotes a main body case, and the main body case 11 is placed horizontally. The main body case 11 has an opening 13 formed at one end side (right side in the drawing) of the front panel 12.

In the main body case 11, a liquid crystal panel 14 and light source means 15 are housed.

The liquid crystal panel 14 has a display surface 16 composed of a plurality of pixels.

The light source means 15 comprises a lamp 31 and a reflector 32, and irradiates the liquid crystal panel 14 with light from the back.

The projection lens 18 is provided in the opening 13 of the front panel 12 and enlarges and projects the light transmitted from the light source means 15 through the liquid crystal panel 14 onto the projection target. Form.

The lens board 19 is made of a metal such as duralumin in the form of a plate. The lens board 19 closes the opening 13 of the front panel 12 with the projection lens 18 attached, and the optical axis of the projection lens 18. A rotation shaft 22 is provided at a position offset from the projection lens 21 by a certain amount.
Are moved in an arc shape, thereby moving the projection lens 18 in the shift direction.

On the lens board 19, a gear portion 23 is formed on a quarter of the outer periphery.

The gear portion 23 is in mesh with a gear 25 attached to a rotating shaft of a motor 24. The motor 24 is
The gear unit 23 is housed in the main body case 11 or the main body case 11 and protrudes outward from the through hole 26 of the main body case 11.
In the embodiment of the present invention, the motor 24 is configured to rotate by a user's operation of the operation panel.

The front panel 12 of the main body case 11 is provided with guide rollers 27 and 28 for preventing the lens board 19 from rattling. Guide rollers 27, 2
8 is in contact with a portion of the lens board 19 where the gear portion 23 is not formed.

The operation of the embodiment of the present invention will be described below.

First, the operation of the optical system will be described. The radiated light of the lamp 31 is converted by the reflector 32 into light that is nearly parallel to an optical axis passing through the center of the lamp 31 and the center of the display surface 16 of the liquid crystal panel 14, and travels toward the liquid crystal panel 14. Light directed to the liquid crystal panel 14 is applied to a display surface 16 of the liquid crystal panel 14.
And enters the projection lens 18. Projection lens 18
Is disposed at a position where the optical axis 21 passing through the center thereof is above the axis 29 of the liquid crystal panel 14 by a distance D1. That is,
The projection lens 18 is arranged at a position where its optical axis 21 does not pass through the center of the display surface 16 of the liquid crystal panel 14. The light transmitted through the display surface 16 of the liquid crystal panel 14 is
As a result, the projected image is projected on a screen arranged above, and an enlarged image of the image of the image signal displayed on the display surface 16 is displayed on the screen.

FIG. 2 is a perspective view showing the liquid crystal projector of FIG. 1, and shows a case where projection is performed vertically.

In FIG. 2, the motor 24 is shifted from the state shown in FIG.
, The gear unit 23 is rotated, the lens board 19 is rotated, and the projection lens 18 is moved in an arc shape, whereby the projection lens 18 is vertically moved in the upper shift direction. In this case, the projection lens 18 is disposed at a position where the optical axis 21 passing through the center thereof is above the axis 29 of the liquid crystal panel 14 by a distance D2. The light transmitted through the display surface 16 of the liquid crystal panel 14 is projected by a projection lens 18 onto a screen disposed above, and a projection image in which an image of a video signal displayed on the display surface 16 is enlarged is displayed on the screen. .

FIGS. 3 and 4 are explanatory diagrams showing the relationship between the display surface of the liquid crystal panel and the image circle of the projection lens in the cases of FIGS. 1 and 2, respectively.

In FIG. 3, reference numeral 41 denotes an image circle of the projection lens 18 in the state of FIG.
Reference numeral 2 denotes an image circle of the projection lens 18 in the state shown in FIG. Since the liquid crystal projector is in a horizontal state, the display surface 16 of the liquid crystal panel 14 is in a horizontally long state.
In this state, the display surface 16 is within the image circle 41 of the projection lens 18, and all the images on the display surface 16 are projected on the screen by the projection lens 18.

The image circle 41 is arranged at a position where the center 43 is located above the axis 29 of the liquid crystal panel 14 by a distance D1.

In FIG. 4, since the liquid crystal projector is in a vertically placed state, the display surface 16 of the liquid crystal panel 14 is in a vertically long state. In this state, the display surface 16 is within the image circle 42 of the projection lens 18, and all the images on the display surface 16 are projected on the screen by the projection lens 18.

The image circle 42 is arranged at a position where the center 44 is located above the axis 29 of the liquid crystal panel 14 by a distance D2. In this state, the image circle 41 of the projection lens 18 in the state of FIG.

FIGS. 5 and 6 are explanatory views showing the projection state of the liquid crystal projector in the cases of FIGS. 1 and 2, respectively.

In FIG. 5, the main body case 11 is placed horizontally, and the projection lens 18 is shifted upward with respect to the liquid crystal panel 14. The image on the liquid crystal panel 14 is displayed by the projection lens 18 as a horizontally long image on a screen 45 arranged on the upper side.

In FIG. 6, the main body case 11 is placed vertically, and the projection lens 18 is shifted upward with respect to the liquid crystal panel 14. The image on the liquid crystal panel 14 is displayed by the projection lens 18 on the screen 46 arranged above as a vertically long image.

According to such an embodiment of the present invention, the lens shift of the projection lens can be performed by rotating the lens board. In this case, since the lens board to which the projection lens is fixed is rotatably supported by the main body case 11 by the rotation shaft 22, a highly accurate lens shift can be performed with a simple structure. Can be closed. This eliminates the need for a slide cover or bellows in the opening 13, thereby reducing manufacturing costs. In addition, even when an electric motor is used as a mechanism for moving the projection lens, the operating force limiting mechanism and the finger pinch detection means are not required. It is unnecessary, and the manufacturing cost can be reduced.
Further, the positional accuracy of the lens can be sufficiently ensured by a simple and lightweight structure, so that the manufacturing cost and the weight can be reduced.

FIG. 7 is a perspective view showing a second embodiment of the liquid crystal projector according to the present invention, and shows a case where projection is performed vertically.

Referring to FIG. 7, in the embodiment of the present invention,
A vertical / horizontal detecting means 51 for detecting whether the main body case 50 is placed vertically or horizontally is provided in the main body case 50, and a motor 53 serving as a lens board rotating means is provided with the lens board 54 based on the detection result of the vertical / horizontal detecting means 51. Is rotated to a predetermined angle.

The lens board 54 closes the opening of the front panel 56 of the main body case 50 with the projection lens 55 attached thereto, and has a rotation axis at a position offset by a fixed amount from the optical axis of the projection lens 55. The projection lens 5 is rotated by the rotation about the rotation axis.
5 is moved in an arc shape, thereby moving the projection lens 55 in the shift direction.

The lens board 54 has a gear portion 57 formed on the outer periphery.

The gear portion 57 is in mesh with a gear 58 attached to the rotating shaft of the motor 53. The motor 53 is
The main body is housed in the main body case 50, and the gear 58 protrudes outward from the through hole 59 of the main body case 50. The other configuration is the same as that of the embodiment of the invention shown in FIG.

The vertical / horizontal detecting means 51 detects that the operation section 52 is vertically set by being pressed, rotates the lens board 54 to a predetermined angle in the case of the vertical installation, shifts the projection lens upward, It is detected that the operation unit 52 is placed horizontally without being pressed, and the projection board is shifted upward by rotating the lens board 54 to a predetermined angle when the operation unit 52 is placed horizontally.

According to such an embodiment of the invention, the same effects as those of the embodiment of the invention shown in FIG. 1 can be obtained, and the vertical and horizontal arrangements are automatically detected to shift the projection lens upward. So the operation becomes easier.

FIG. 8 is a perspective view showing a third embodiment of the liquid crystal projector according to the present invention. The same components as those in the embodiment of FIG. Omitted.

Here, when the liquid crystal projector is used in a vertical position, the possibility of accidental overturning increases, and in order to prevent this, it is conceivable to add an overturn preventing leg (overturn preventing member). Considering convenience during transportation, it is preferable that the foot be a foldable type that is stored in the main body or a detachable type.

In FIG. 8, in the embodiment of the present invention, a retractable overturn preventing member 61 for preventing the overturn of the main body case when the main body case is placed vertically, and whether or not the overturn preventing member is in use is detected. The use state detecting means 62 provided in the main body case 60 and the motor 5 serving as a lens board rotating means
3 rotates the lens board 54 to a predetermined angle based on the detection result of the use state detecting means 62.

The overturn prevention member 61 is rotated to the outside and comes to the drawn-out position shown by the solid line, and is put into a use state to prevent the body case 60 from overturning. State.

The use state detecting means 62 includes the overturn prevention member 6.
1 is located at the position shown by the solid line, it is detected that the camera is in the vertical position, the lens board 54 is rotated to a predetermined angle in the case of the vertical installation, the projection lens is shifted upward,
When 1 comes to the position shown by the broken line, it is detected that the camera is in the horizontal position, and the lens board 54 is rotated to a predetermined angle in the case of the horizontal setting to shift the projection lens upward.

According to such an embodiment of the invention, the same effect as that of the embodiment of the invention shown in FIG. 1 can be obtained. In addition, since the projection lens is shifted upward by the movement of the overturn prevention member 61, the operation can be performed more easily. It's easy.

In the embodiment of the present invention, the overturn prevention member 61 is of a retractable type, but the overturn prevention member 61 may be of a detachable type.

FIG. 9 is a perspective view showing a fourth embodiment of the liquid crystal projector according to the present invention. The same components as in the embodiment of the invention shown in FIG. Omitted.

Referring to FIG. 9, in the embodiment of the present invention,
A retractable overturn preventing member 71 for preventing the body case 70 from overturning in a vertically placed state, and a rotation axis of lens board rotating means for rotating the lens board 54 at a predetermined angle in mechanical cooperation with the overturn preventing member. 81, a gear 72, and relay gears 73, 74, 75.

The fall prevention member 71 is fixedly attached to one end of a rotating shaft 81 rotatably provided on the front panel 76 of the main body case 70, and is provided on the outer surface of the front panel 76. The other end of the rotating shaft 81 is on the inner surface side of the front panel 76, and the gear 72 is attached and fixed.
The relay gears 73 and 74 are rotatably provided on the inner side of the front panel 76. The gear 72 is a relay gear 73
The relay gear 73 is in mesh with the relay gear 74. The relay gear 75 is rotatably provided by a bearing (not shown).
And the other end projects into the inner surface of the front panel 76 and engages with the relay gear 74.

When the main body case 70 is placed vertically,
The overturn prevention member 71 is moved to the position shown. As a result, the projection lens 55 is shifted upward when the lens board 54 reaches a predetermined angle when the lens board 54 is placed vertically. Body case 70
When performing the horizontal placement, the fall prevention member 71 is rotated by 180 degrees to a position on the opposite side from the illustration. As a result, the rotation shaft 81, the gear 72, and the relay gears 73, 74, and 75 rotate to rotate the lens board 54 to a predetermined angle when the lens board 54 is placed vertically, thereby shifting the projection lens 55 upward.

According to such an embodiment of the invention, the same effects as those of the embodiment of the invention of FIG. 7 can be obtained, and in the embodiment of the invention of FIG.
Is not mechanically linked with the movement of the overturn prevention member 71, so a driving motor is required. However, the structure can be simplified by mechanically connecting as shown in FIG.

In the embodiment of the invention shown in FIGS. 1 and 9, the projection lens enlarges and projects the light emitted from the light source means through the liquid crystal panel onto the projection object, but reflects the light from the liquid crystal panel. Light may be enlarged and projected on the projection target.
Although the screen is used as the projection target, the projection may be performed on another projection target, for example, a wall or the like.

[0063]

As described above, according to the present invention, a highly accurate lens shift can be performed with a simple structure, and the opening of the front panel can be closed. Does not require a slide cover or bellows, reducing manufacturing costs.Also, when using an electric type as a mechanism for moving the projection lens, there is no need for an operating force limiting mechanism or finger pinch detection means, reducing manufacturing costs. Can be reduced. Further, the positional accuracy of the lens can be sufficiently ensured by a simple and lightweight structure, so that the manufacturing cost and the weight can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a liquid crystal projector according to the present invention.

FIG. 2 is a perspective view showing a case where projection is performed in a vertical arrangement of the liquid crystal projector of FIG. 1;

FIG. 3 is an explanatory diagram showing a relationship between a display surface of a liquid crystal panel and an image circle of a projection lens in the case of FIG. 1;

FIG. 4 is an explanatory diagram showing a relationship between a display surface of a liquid crystal panel and an image circle of a projection lens in the case of FIG. 2;

FIG. 5 is an explanatory diagram showing a projection state of the liquid crystal projector in the case of FIG.

FIG. 6 is an explanatory diagram showing a projection state of the liquid crystal projector in the case of FIG.

FIG. 7 is a perspective view showing a liquid crystal projector according to a second embodiment of the present invention;

FIG. 8 is a perspective view showing a liquid crystal projector according to a third embodiment of the present invention.

FIG. 9 is a perspective view showing a liquid crystal projector according to a fourth embodiment of the present invention.

FIG. 10 is a perspective view showing a conventional liquid crystal projector.

11 is an explanatory diagram showing another problem of the liquid crystal projector of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Main body case 12 Front panel 13 Opening 14 Liquid crystal panel 15 Light source means 16 Display surface 18 Projection lens 19 Lens board 22 Rotation axis

Claims (4)

[Claims] A main body case having an opening formed in a front panel; a liquid crystal panel housed in the main body case and having a display surface formed of a plurality of pixels; a liquid crystal panel housed in the main body case; Light source means for irradiating light, light provided at an opening of the front panel, and light emitted from the light source means transmitted through the liquid crystal panel, or
A projection lens that forms a projection screen by enlarging and projecting the light reflected by the liquid crystal panel onto a projection target; and closing an opening of the front panel with the projection lens attached, and an optical axis of the projection lens. A lens board provided with a rotation axis at a position offset by a predetermined amount from the lens, and rotating the projection lens in the shift direction by rotating about the rotation axis. 2. Vertical and horizontal detecting means for detecting whether the main body case is placed vertically or horizontally, and lens board rotating means for rotating the lens board to a predetermined angle based on the detection result of the vertical and horizontal detecting means. The liquid crystal projector according to claim 1, further comprising: 3. A retractable or detachable overturn prevention member for preventing the body case from overturning when the main body case is placed vertically, use state detection means for detecting whether or not the overturn prevention member is in use, and this use state. 2. The liquid crystal projector according to claim 1, further comprising: lens board rotating means for rotating said lens board at a predetermined angle based on a detection result of said detecting means. 4. A retractable or detachable overturn preventing member for preventing the body case from overturning in a vertical position, and a lens for rotating the lens board at a predetermined angle mechanically in conjunction with the overturn preventing member. The liquid crystal projector according to claim 1, further comprising: board rotating means.