JP3526253B2 - Composite LCD projector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite type liquid crystal projector in which an object is placed on a transparent mounting table, the surface of the object is illuminated by illuminating from below, and the image is enlarged and projected on a screen.

[0002]

2. Description of the Related Art Recently, a so-called overhead projector (hereinafter referred to as "object O") capable of enlarging and projecting an opaque subject as it is as a device for presentations used in conferences, lectures at universities, etc. without using a conventional transparent sheet.
HP has been proposed (eg, JP-A-5-198).
849, JP-A-7-104713, etc.).

Such an object OHP is shown in FIGS.
As shown in FIG. 3, the opening 3 provided on the upper surface 2 of the housing 1 is covered with a transparent glass plate to form a mounting table 4, and a surface (projection surface) on which the subject 5 such as a document is to be projected is placed on the mounting table 4. It is placed face down, this projection surface is illuminated by light from light sources 6 provided on both sides below the mounting table 4, and the reflected light reflected on the projection surface is guided to the TV camera 9 by the reflectors 7 and 8. The configuration is such that an image is picked up, the image signal is converted into optical information by a projection optical system (not shown), and enlarged and projected on a screen (not shown) by the projection lens 10.

As the light source 6 for projecting the subject 5, a fluorescent lamp is usually used. The projection optical system is composed of a light source unit and an optical system, and the light source unit is generally composed of a light source such as a halogen lamp and a metal halide lamp, and a reflector that reflects light from the light source into parallel light. An optical system generally has two dichroic mirrors that split the light emitted from a light source into monochromatic lights of red, blue, and green, and the light reflected and transmitted by these dichroic mirrors is modulated to red,
It is composed of three liquid crystal panels that emit blue and green image lights, a dichroic prism that combines the image lights modulated by these liquid crystal panels, and a projection lens that projects the combined image lights onto a screen.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the HP, the light source 6, the reflector 7,
A subject projection system 11 including 8 and the like, a TV camera 9 and a projection optical system are housed and integrated. In that case, since it is necessary to secure the optical axis length of the subject projection system 11, in other words, the optical path length from the mounting table 4 to the TV camera 9, the entire apparatus becomes large, which is not only portable but also has a wide storage space. There was a problem of needing it.

The present invention has been made in order to solve the above-mentioned conventional problems, and an object of the present invention is to reduce the size of the apparatus, improve the portability, and reduce the storage space, and the manufacturing cost. Another object of the present invention is to provide a composite-type liquid crystal projector that can reduce the power consumption.

[0007]

In order to achieve the above object, a first invention is an illumination device for illuminating a projection surface of a subject placed on a transparent mount from below the mount. In a composite liquid crystal projector including a camera for capturing an image of a projection surface of a subject and a projection optical system for projecting an image captured by the camera onto a screen, the camera and the projection optical system are provided in a housing whose one side is open. A cover that is housed, is attached to the open portion of the housing so that it can be opened and closed with the upper end as a pivot, and is held substantially horizontally during use, and a mounting table on which the subject is placed is provided on the surface of the cover. The illumination device and a reflector for guiding the image of the subject to the camera are rotatably arranged inside.

A second invention is the same as the first invention,
The structure is such that the cover is supported by the reflector when used.

In the present invention, the cover is opened and held horizontally during use, and the subject is placed on the mounting table with the projection surface facing downward. This increases the distance from the mounting table to the camera. The reflector is housed behind the mounting table when not in use, and is drawn out from the cover when used to support the cover and guide light from the light source reflected by the projection surface of the subject to the camera.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail based on the embodiments shown in the drawings. 1 is a schematic block diagram showing an embodiment in which a composite liquid crystal projector according to the present invention is applied to an object OHP, FIG. 2 is an external perspective view of the projector when not in use, and FIG. FIG. 4 is a view showing the projection optical system, FIG. 5 is a sectional view of the light source unit, and FIGS. 6A and 6B are front views when not in use and a state in which the cover is opened.

1 to 3, the object OHP20 is
An image such as characters and figures written on the projection surface of the subject 5 placed on the placing table 4 is configured to be enlarged and projected on the screen 21. Further, when the image signal from the computer 22 is received by the signal cable 23 or the antenna 24, the image of the computer 22 is also enlarged and projected on the screen 21.

Further, the structure of the object OHP20 is shown in FIG.
More specifically, referring to FIG. 6, the object OHP 20 includes a vertically long thin box-shaped casing 25 having an open right side surface and the casing 25.
The housing 2 is provided with an openable and closable cover 26 that covers the open side surface of the housing 2.
TV camera in 5 (example: CCD solid-state imaging device) 9
6 and a projection optical system 27 are housed. When not in use, the entire subject projection system 28 is housed in the cover 26, and when used, as shown in FIGS. 3 and 6B. A reflector 57, which is a component of the subject projection system 28, is drawn out downward to support the cover 26.

A projection optical system 27 is provided on the front surface of the housing 25.
The projection lens 10 constituting a part of the above is attached, and the fixed leg 29 and the movable leg 30 are attached to the lower surface. The fixed legs 29 are fixed to the front and rear end portions of the lower surface of the housing 25 on the side opposite to the cover 26 side. The movable leg 30 is
When the cover 26 is opened, the object OHP2
0 is used to prevent it from falling toward the cover 26 side, and is attached to the lower surface of the housing 25 at the end opposite to the fixed leg 29 so as to be slidable or rotatable in the left-right direction. When the OHP 20 is used, it is pulled out below the cover 26.

In FIG. 4, the projection optical system 27 separates (splits) the source light of all wavelengths into red (R), green (G), and blue (B) monochromatic lights by color separation (dichroic) mirrors. , These R, G, and B lights are made incident on the black and white liquid crystal panel provided for each color, and the R image, G
An image and a B image are generated and mixed by a dichroic prism or a dichroic mirror, and a color image is reproduced on the projection lens 10. A light source 31 such as a xenon lamp is used.
Is equipped with. The light source light emitted from this light source 31 is
After being made parallel by the parabolic reflection surface 31a and then incident on the first dichroic mirror 32, only red light of the light source light is transmitted and light of other colors is reflected. The red light that has passed through the first dichroic mirror 32 passes through the total reflection mirror 33 and the condenser lens 34 and enters the first liquid crystal panel 35. When the reflected light reflected by the first dichroic mirror 32 is incident on the second dichroic mirror 36, blue light is transmitted and green is reflected. The green light reflected by the second dichroic mirror 36 is transmitted through the condenser lens 37 and
Is incident on the liquid crystal panel 38. On the other hand, the blue light transmitted through the second dichroic mirror 36 is reflected by the total reflection mirror 3
After total reflection by 9, 40, condenser lens 41
And is incident on the third liquid crystal panel 42.

The first, second and third liquid crystal panels 35,
An image signal from the TV camera 9 or the computer 21 is supplied to each of the constituent pixels 38 and 42 through a signal processing circuit or the like, and the red light passing through the first liquid crystal panel 35 generates an image signal. It becomes the red image light that it has. Second
The green light that has passed through the liquid crystal panel 38 becomes a green image light having an image signal. Also, the blue light that has passed through the third liquid crystal panel 42 becomes blue image light having an image signal. Then, these image lights are combined by the dichroic prism 43 to become RGB additive color mixed image lights, which are enlarged and projected on the screen 21 by the projection lens 10 to reproduce a color image. Such a projection optical system 27 is conventionally known. In addition, the projection optical system 27
It is possible to use various types as well as those shown in FIG.

In FIG. 3, the TV camera 9 is provided so as to project from the open side surface of the housing 25 toward the cover 26 side, and is provided with a total reflection fixed mirror 50. The fixed mirror 50 is vertical and inclined with respect to the left and right directions (eg, 45 °).
is doing.

Further, a support member 51 that supports the reflection plate 57 when the object OHP20 is used is accommodated below the inside of the casing 25 by a slide guide 52 so as to be drawn out to the side of the casing 25. When the support member 51 is pulled out by a predetermined amount, the support member 51 is locked by an appropriate locking mechanism (not shown), and a locking portion 53 having a triangular concave portion on the tip surface.
Are formed.

The cover 26 has the same size as the housing 25, is formed in a box shape with an open side surface facing the open side surface of the housing 25, and an upper end thereof is rotatable in the vertical direction by a hinge 54. It is pivotally supported. An opening 55 is formed in the center of the surface 26a of the housing 26, and the opening 55 is covered with the mounting table 4 made of a transparent glass plate. Further, a light shielding cover 56 that covers the mounting table 4 is provided on the surface 26a.

When not in use, the subject projection system 28 housed inside the cover 26 is composed of two fluorescent lamps which illuminate the projection surface of the subject 5 mounted on the mounting table 4 from below. The light source (illumination device) 6 and the reflection plate 57 and the fixed mirror 50 that totally reflect the reflected light emitted from the light source 6 and reflected on the projection surface of the subject 5. Light source mounting members 59 are arranged on the left and right sides of the mounting table 4 on the rear surface side of the cover 26, and the light sources 6 are mounted on these light source mounting members 59. The light emitted from the light source 6 is guided to the inside of the transparent acrylic plate 61 (FIG. 5), and is reflected by the back surface thereof to be emitted from the front side and projected on the projection surface of the subject 5 mounted on the mounting table 4. Irradiate.

The side edge of the reflection plate 57 on the side opposite to the housing 25 side is rotatably supported inside the cover 26 by a ratchet mechanism 63, and is usually shown in FIG. 6 (a). As described above, it is housed along the back surface of the acrylic plate 61 so as to cover the open side surface of the housing 25. At the time of projection (in use), as shown in FIG. 6B, the cover 26 is opened, the support member 51 is pulled out from the housing 25, and then the support member 51 is rotated and pulled out below the cover 26, and the lower end is supported. Member 5
It is configured to be locked by one locking portion 53. When the lower end of the reflection plate 57 is locked by the locking portion 53, the reflection plate 57 horizontally supports the cover 26, whereby the optical path from the surface of the mounting table 4 to the TV camera 9 has a predetermined length. An image of the projection surface of the subject 5 is formed on the light receiving surface of the TV camera 9. In addition, when returning from the used state to the unused state, the reflection plate 57 is attached to the locking portion 5 of the support member 51.
When removed from 3, the cover 26 rotates and closes due to its own weight. Therefore, it is desirable to provide the housing 25 with a locking member such as a stay that locks the cover 26 in a substantially horizontal state. With this configuration, when the cover 26 is opened, the cover 26 can be temporarily fixed to the housing 25 by the locking member to prevent the cover 26 from falling. Therefore, the reflection plate 57 is rotated to be housed in the cover 26. When doing so, it is not necessary to hold the cover 26 by hand.

Of the pair of light source mounting members 59 to which the light source 6 is mounted, the light source mounting member 59 on the hinge 54 side is
Although not shown, an appropriate locking member that locks the reflection plate 57 is provided. The reason why the reflection plate 57 is pivotally supported by the ratchet mechanism 63 is that the cover 26
This is to prevent a sudden rotation drop due to its own weight when the reflector is opened and the reflection plate 57 is rotated downward. The mechanism for preventing such a rapid rotation drop is not limited to the ratchet mechanism 63, and a friction mechanism may be used.

According to the object OHP 20 having such a structure, the optical path length from the surface of the mounting table 4 to the TV camera 9 can be shortened when the cover 26 is closed as shown in FIG. Since the cover 26 can be extended to a predetermined length by opening the cover 26 as shown in FIG. 6B during use, the bulk capacity of the entire device when not in use can be reduced. Therefore, it is highly portable, and the carrying case for storing the object OHP20 and the storage space can be reduced.

If the entire apparatus becomes smaller, the housing 25
Since the size of the mold is also small, the mold clamping pressure can be reduced, and molding can be performed with a medium-sized injection molding device (5MN / 500t or less). Therefore, the manufacturing cost can be reduced.

[0024]

As described above, according to the composite type liquid crystal projector of the present invention, the cover is provided so as to be openable and closable with respect to the housing, and the illumination device for illuminating the subject and the image of the subject are provided in the cover. Since the reflecting plate leading to the camera is rotatably arranged, the entire apparatus can be downsized, easy to carry, and the storage space can be reduced. In addition, manufacturing cost can be reduced by miniaturization.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing an embodiment in which a composite liquid crystal projector according to the present invention is applied to an object OHP.

FIG. 2 is an external perspective view of the projector when not in use.

FIG. 3 is a cross-sectional view of a usage state.

FIG. 4 is a diagram showing a projection optical system.

FIG. 5 is a sectional view of a light source unit.

6 (a) and 6 (b) are a front view when not in use and a view showing a state in which a cover is opened.

FIG. 7 is a front view of a conventional object OHP.

FIG. 8 is a sectional view of the same OHP.

[Explanation of symbols]

4 ... Mounting table, 5 ... Subject, 6 ... Light source, 10 ... Projection lens, 20 ... Liquid crystal projector, 25 ... Housing, 26 ... Cover, 27 ... Projection optical system, 28 ... Subject projection system, 51 ... Support member, 57 …a reflector.

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Claims (2)

(57) [Claims] 1. A lighting device for illuminating a projection surface of a subject placed on a transparent mounting base from below the mounting base, a camera for capturing an image of the projection surface of the subject, and an image captured by the camera. In a composite type liquid crystal projector having a projection optical system for projecting an image on a screen, the camera and the projection optical system are housed in a housing whose one side is open, and the opening of the housing is opened and closed with the upper end as a pivot. A cover that is freely attached and is held substantially horizontal during use is installed, and a mounting table on which the subject is placed is provided on the surface of the cover. Inside the reflection device that guides the illumination device and the image of the subject to the camera. A composite liquid crystal projector having a plate rotatably arranged. 2. The composite liquid crystal projector according to claim 1, wherein the cover is supported by a reflecting plate when in use.