JPH09185122A - Portable overhead projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the drastic miniaturization and lightening of an entire projector and make the projector excellent in portability. SOLUTION: This projector where a projection unit 1 and a stage base 2 are coupled through an arm part 3 so that they can be folded is used in a state where the unit 1 is held to be opposed to the stage base 2 by the arm part 3. Then, the unit 1 is provided with a light source part 14, a projection lens 16 and an electric circuit part inside, and the electric circuit part is divided to a filter circuit 32, a voltage conversion circuit 33, etc., and mounted in the unit 1. Therefore, the respective circuits are dispersedly mounted in gaps in the unit 1, whereby mounting density is enhanced, the projector is drastically miniaturized and lightened as a whole, and the projector is made excellent in the portability. Since the circuits are dispersedly mounted in accordance with circuit functions, the entire electric circuit need not be exchanged but only the necessary circuit is exchanged in the case of exchanging the electric circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable overhead projector.

[0002]

2. Description of the Related Art In an overhead projector, an image projection sheet as an original document on which an image to be projected is printed is placed on a stage table, and the image projection sheet is irradiated with light from a light source section to produce an image. An image on the projection sheet is enlarged and projected on a screen by a projection lens. The image projection sheet used in this overhead projector is a transparent sheet on which an image for projection is printed, and information such as documents and images created by a popular personal computer or word processor can be easily printed by a printer. A4 size paper is widely used for printing.

[0003]

By the way, such an overhead projector is required to be excellent in carrying in order to strongly support sales activities of a salesperson, and various types have been developed in response to this. Although it has been commercialized, since the image projection sheet can be used up to A4 size, the stage table cannot be made smaller than the A4 size image projection sheet,
It is difficult to further reduce the size, and for this reason, it is the current situation that a salesperson cannot put it in a bag or a bag and carry it easily.

In order to meet such a situation, the inventor of the present application pays attention to the size of the image projecting sheet and reduces the size of the image projecting sheet, thereby reducing the size, weight and carrying of the entire apparatus. I examined the sex. As a result, it has been found that there are various problems as follows. If you reduce the size of the image projection sheet to a notebook size,
Since it cannot be conveyed by a feed roller such as a printer or a copying machine, information created by an existing personal computer or word processor cannot be easily printed by the printer, or the printed matter cannot be copied by the copying machine. Therefore, a special device such as a photographic system is required. Further, if it is possible to use a small-sized image projection sheet, it is possible to reduce the size of the stage table by making the stage stand small. However, in this overhead projector, the light source unit, the projection lens, and Since various parts such as electric circuits are required, it is not possible to achieve sufficient miniaturization simply by incorporating these parts, and it has excellent portability so that a salesperson can carry it in a bag or bag. You don't always get something. Moreover, even if it is excellent in portability, a clear and good projected image cannot be obtained unless the light utilization efficiency from the light source unit and the optical path length from the light source unit to the projection lens are sufficiently secured. Also, if the light source part is troublesome to replace during use, usability is poor.

A first object of the present invention is to make an image projection sheet, which is a document, finally as large as a notebook size, so that the overall size and weight of the apparatus can be greatly reduced and the portability can be improved. Is to get a good one. A second object of the present invention is to easily replace the light source unit,
It is to be able to obtain something that is easy to use. Further, a third object of the present invention is to sufficiently secure the light utilization efficiency from the light source unit and the optical path length from the light source unit to the projection lens so that a clear and good projected image can be obtained. is there.

[0006]

The invention according to claim 8 is
In order to achieve the first problem, the image projection sheet placed on the stage table and pressed by the sheet pressing plate is
It is characterized in that image information is formed into a printable size by a printer or a copying machine, and perforations are formed after the printing for cutting into a specified size of a notebook size. Therefore, according to the invention of claim 8, a special device such as a photographic system is not required, and information such as a document or an image created by an existing personal computer or a word processor is printed on the image creating sheet by a printer. Or, you can make a reduced copy with a copier, and cut the printed image projection sheet with perforations,
You can easily and easily create an image projection sheet that is about the size of a notebook, which allows you to form a stage stand about the size of a notebook, greatly reducing the size of the entire device, and Weight reduction is possible.

In order to achieve the first object, the invention according to claim 1 foldably connects the projection unit and the stage base via the arm portion, and the projection unit is opposed to the stage base by the arm portion. A portable overhead projector to be used while being held, in which a light source section, a projection lens, and an electric circuit section are provided in a projection unit, and the electric circuit section is divided according to the circuit function of a filter circuit, a voltage conversion circuit, etc. And is mounted in the projection unit. Therefore, according to the invention described in claim 1, since the electric circuit portion is divided according to the circuit function of the filter circuit, the voltage conversion circuit, and the like, each circuit can be distributed and mounted in the gap in the projection unit. This makes it possible to increase the packaging density, greatly reduce the size and weight of the entire device, and obtain a highly portable device, which is distributed according to the circuit function. So when you replace the electrical circuit,
It is not necessary to replace the entire electric circuit, and only the necessary circuit can be replaced.

In this case, a cooling fan is provided in the projection unit in addition to the light source section, the projection lens, and the electric circuit section, and the electric circuit section is provided in addition to the filter circuit and the voltage conversion circuit. The fan control circuit for driving and controlling the cooling fan may be mounted separately. Further, as described in claim 3, if the arm portion has a structure in which the projection unit and the stage base are folded and housed, a very portable one can be obtained. Further, as described in claim 4, if the projection unit is fixed to the arm portion at the time of storage and a lock mechanism for fixing the stage base to the arm portion at the time of use is provided, at the time of storage by this lock mechanism. Alternatively, since the projection unit or the stage base can be securely fixed to the arm portion during use as needed, the number of lock mechanisms can be reduced, and the number of parts can be reduced. Further, as described in claim 5, when the projection unit is housed in the arm part, the projection unit is turned off, and if the power supply switch for cutting off the power supply to the electric circuit part is provided, the light source part is turned on when being carried. The inside of the projection unit can be surely prevented from being heated, and a highly safe one can be obtained.

If a transparent sheet pressing plate for pressing an image projecting sheet, which is an original, is rotatably provided on the stage table as described in claim 6, heat from the light source unit and image projecting sheet can be used during use. It is possible to prevent the image projection sheet from curling due to the peculiarities of the sheet itself, and it is possible to project a good image without distortion. Further, as described in claim 7, a shaft portion having a rectangular cross section is provided at both ends of the sheet pressing plate so as to project, and the shaft portion is rotatably mounted on the stage base on the side connected to the arm portion. If a bearing portion is provided and an insertion groove having a width corresponding to the short side of the sectional shape of the shaft portion is provided on the bearing portion toward the side connected to the arm portion, the stage base is connected to the arm portion. Before mounting, the shaft can be easily inserted into the bearing by inserting it from the bearing's insertion groove, and even if you try to remove the shaft from the insertion groove when the stage base is connected to the arm, Since the holding plate contacts the arm, the shaft does not come off from the bearing.

In order to achieve the second object, the invention according to claim 9 is provided with a projection unit provided with a light source section and a projection lens, and a reflection plate for reflecting light from the light source section toward the projection lens. In a portable overhead projector including a stage table, the light source unit includes a light source and a reflector that reflects light from the light source, and the light source unit is detachably attached to the projection unit via an elastic member and can be mounted in any direction. The front peripheral portion of the reflector is positioned by being pressed against the position regulating member of the projection unit by the elastic force of the elastic member. Therefore, this claim 9
According to the above-mentioned invention, since the light source unit is attached to the projection unit so as to be displaceable in any direction via the elastic member, the front peripheral portion of the reflector is projected even if the outer dimensions of the light source unit vary. By pressing the position regulating member of the unit by the elastic force of the elastic member, the optical axis can be made constant, so that the light source section can be easily attached and replaced, and a convenient one can be obtained.

In this case, the light source unit is detachably attached to the light source opening / closing lid provided in the projection unit via the elastic member, and the light source opening / closing lid is movable to the projection unit. If it is provided so as to be rotatable around the support shaft attached in this state, the light source unit can be easily attached and detached by rotating and opening the light source opening / closing lid about the support shaft. After attaching the light source unit to the light source opening / closing lid, when rotating the light source opening / closing lid in the closing direction, or by shifting the support shaft, the peripheral portion of the front surface of the reflector is adjusted to the position regulating member of the projection unit. The elastic force of the elastic member can be surely pressed against the optical axis, and the optical axis can be fixedly positioned by this, so that the light source section can be attached and replaced very easily.

According to the eleventh aspect of the present invention, a heat insulating plate for shielding radiant heat from the light source section is provided around the light source section,
If the cut-and-raised portions that are inclined along the outer peripheral surface of the light source section are provided on the heat insulating plate in correspondence with the light source opening / closing lid, parts such as the electric circuit section and the light source opening / closing lid provided around the light source section can be provided. It is possible to prevent heating by radiant heat from the light source section, and furthermore, by providing the heat-insulating plate with the cut-and-raised portion corresponding to the light source opening / closing lid, an opening corresponding to the cut-and-raised portion is formed in the heat-insulating plate. Therefore, for example, if a large number of ventilation holes are provided in the light source opening / closing lid, the air heated in the light source section can be discharged to the outside from the ventilation hole of the light source opening / closing lid through the opening of the heat insulating plate. This makes it possible to efficiently cool the light source unit.

According to a twelfth aspect of the present invention, the projection unit comprises a projection mirror for reflecting the projection light from the projection lens, a standing upside down mechanism for standing up the projection mirror at a predetermined angle, and a standing upside down mechanism. With an angle adjusting mechanism that finely adjusts the standing angle of the projection mirror that has been erected at a predetermined angle, the projection mirror can be erected at a predetermined angle by the erection sideways mechanism only by erecting the projection mirror. Moreover, the upright angle of the projection mirror can be finely adjusted by the angle adjusting mechanism, and thus the projected image can be reliably and satisfactorily projected at a desired position.

According to a thirteenth aspect of the present invention, in order to achieve the third object, in a portable overhead projector in which light from a light source section is reflected by a Fresnel mirror and condensed on a projection lens, a reflecting surface of the Fresnel mirror is provided. Of the light emitted from the light source to the Fresnel mirror, it is formed on an aspherical surface with a radius of curvature that is smaller in the peripheral area than in the central area.
The light in the peripheral area can be reliably focused on the projection lens, which improves the efficiency of use of the light, prevents a decrease in illuminance in the peripheral area of the projected image, and provides a projected image with almost uniform brightness over the entire area. In addition to being obtainable, the light from the light source section is reflected by the Fresnel mirror and condensed on the projection lens, so that the optical path length from the light source section to the projection lens can be sufficiently secured. In this case, as described in claim 14, if the center of the Fresnel mirror is deviated from the light source unit side toward the projection lens side, the light from the light source unit can be sufficiently incident on the projection lens, and the projection lens is projected. The brightness of the entire image can be improved.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
An embodiment of the portable overhead projector of the present invention will be described. 1 is a perspective view of the portable overhead projector when in use, FIG. 2 is a side view showing a state in which a stage base is folded into an arm portion of the portable overhead projector, and FIG. 3 shows a folding process following FIG. FIG. 6B is a side view showing the state in which the projection unit is folded into the arm portion in which the stage base is housed. This portable overhead projector comprises a projection unit 1, a stage base 2, and an arm section 3,
The projection unit 1 and the stage base 2 are foldably connected to each other via an arm 3 and the projection unit 1 and the stage base 2 are connected to each other as shown in FIG. The size folded and stored in the arm portion 3 is configured to be substantially the same as the size of the Bible of B6 size.

That is, the arm portion 3 is made of a synthetic resin or metal, and as shown in FIG. 1, is formed in a substantially box shape with its upper surface and right side surface opened, and its size is B6.
The size of the Bible is approximately the same, for example, the width is about 130 mm, the height is about 180 mm, and the thickness is about 50 mm. A bearing portion 4 is provided on the inner side of the lower portion of the arm portion 3 between the facing surfaces 3a, and the bearing portion 4 is provided at both ends of one end portion (the left end portion in FIG. 1) of the stage base 2. The stage-side support shaft 5 is attached so as to be rotatable. A projection unit side support shaft 6 is provided on the facing surface 3a at the upper inside of the arm portion 3, and the projection unit 1 support shaft 6 is provided on the projection unit side support shaft 6.
One end portion (the left end portion in FIG. 1) of the unit case 7 is attached. Further, the projection unit side support shaft 6 is provided with a rotary frictional force imparting mechanism (not shown) for imparting a rotational frictional force, and the projection unit 1 causes the arm portion 3 to rotate at a predetermined rotational force by the rotational frictional force imparting mechanism. With the above, it is rotatable.

The stage base 2 is made of synthetic resin or the like,
As shown in FIGS. 1 and 2, the inner surface 3 on the back side of the arm portion 3
It is formed in a flat plate shape having substantially the same size as b, rotates about the stage support shaft 5 and is housed inside the arm part 3 and at the other end side of the arm part 3 (see FIG. The right end portion of the stage 3 is projected horizontally, and the stage base 2 is attached to the lower surface 2a of the other end of the stage base 2 protruding from the arm portion 3.
It has a structure in which a leg portion 2c is provided for horizontally holding the upper surface 2b of the stage base 2 when it is horizontally projected from the. The upper surface 2b of the stage base 2, that is, the arm portion 3
As shown in FIG. 1, a Fresnel mirror (reflection plate) 8 is installed on one surface corresponding to the inner surface 3b on the back side of the. On the Fresnel mirror 8, an image projection sheet 9 of a notebook size, which will be described later, is placed, and a transparent sheet pressing plate 10 that presses the image projection sheet 9 is rotatably attached.

Next, with reference to FIGS. 4 and 5, the mounting structure of the sheet pressing plate 10 will be described. As shown in FIG. 4, a shaft portion 11 having an L-shaped planar shape and a rectangular cross-sectional shape is provided at both ends of one end portion (the left end portion in the drawing) of the sheet pressing plate 10 so as to project. . Further, a bearing portion 12 on which a shaft portion 11 is rotatably mounted is provided on the stage base 2 on the side connected to the arm portion 3, that is, on one end side (the left end side in the figure) of the stage base 2. There is. As shown in FIG. 5A, the bearing portion 12 is provided with an insertion groove 13 having a width a2 corresponding to the short side a1 of the cross-sectional shape of the shaft portion 11 toward the side connected to the arm portion 3. ing. Then, as shown in FIG. 5B, the seat pressing plate 10 is rotatably attached to the stage base 2 by inserting the shaft portion 11 into the insertion groove 13 of the bearing portion 12 in the arrow direction. There is. In this case, the shaft portion 1 of the sheet pressing plate 10
Since the cross-sectional shape of 1 is rectangular, when the stage base 2 is connected to the arm part 3, even if the shaft part 11 is taken out from the insertion groove 13, the sheet pressing plate 10 abuts on the arm part 3, so that the bearing The shaft portion 11 does not come off from the portion 12.

The unit case 7 of the projection unit 1 is made of synthetic resin or the like, and is formed to be a little smaller than the internal shape of the arm portion 3 as shown in FIGS. It is structured to be stored together with 2. FIG. 6 is a plan view showing the inside of the unit case 7. As shown in FIGS. 1 and 6, a light source unit 14, a total reflection mirror 15, a projection lens 16, a cooling fan 17, and an electric circuit unit, which will be described later, are provided in the unit case 7.

As shown in FIG. 7, the unit case 7 is provided with a light source opening / closing lid 18 having a ventilation hole 18a extending from the upper surface to one side surface. The light source unit 14 is provided on the inner surface of the light source opening / closing lid 18 corresponding to one side surface of the unit case 7 via an upper heat insulating plate 19 described later. The light source unit 14 includes a light source 14a such as a halogen lamp and a reflector 14b that reflects light from the light source 14a. As shown in FIG. 8, four heat insulating plates 19 to 22 for cutting off radiant heat from the light source unit 14 are provided around the light source unit 14.

As shown in FIGS. 7 and 9, a socket 24 is provided on the upper heat insulating plate 19 via an elastic member 23 such as a coil spring, and the light source unit 14 is detachably provided on the socket 24. The portion 14 can be displaced in any direction by the elastic member 23. And FIG.
As shown in (A) and (B), the light source opening / closing lid 18 is rotatably provided around a support shaft 25 movably attached to the unit case 7. That is, the support shafts 25 projecting from both side surfaces of the light source opening / closing lid 18
Is movably inserted into the elongated slot 26 formed in the unit case 7 in a rotatable state. A position regulating plate 27 is provided in front of the light source unit 14 (on the right side in the figure). This position regulating plate 27
As shown in FIG. 8, is bent in an L shape, its rising portion is formed in the position regulating portion 28, and the lower horizontal portion is the lower heat insulating plate 20. The position regulating portion 28 has an opening 28a corresponding to the inner diameter of the tip circle of the reflector 14b.
And the positioning protrusion 28b is provided. Then, as shown in FIG. 10 (A), when the light source opening / closing lid 18 is pushed in the horizontal direction, the support shaft 25 is moved into the elongated hole 2.
The light source opening / closing lid 18 is closed at the lower end of the light source 6. In this state, the peripheral portion of the front surface of the reflector 14b is located at the position regulating portion 2
The elastic force of the elastic member 20 is pressed against the elastic member 8 and the outer peripheral surface of the reflector 14b is brought into contact with the positioning protrusion 28b to be positioned. Further, as shown in FIG. 10B, when the light source opening / closing lid 18 is pulled up in the horizontal direction and is raised, the support shaft 25 is positioned at the upper end of the elongated hole 26 and the light source opening / closing lid 18 is opened. When the light source opening / closing lid 18 is rotated in this state, the light source unit 14 can be taken out as shown in FIG. 7.

As shown in FIG. 8, the upper heat insulating plate 19 among the four heat insulating plates 19 to 22 in the periphery of the light source section 14 is L.
The lower heat insulating plate 20 corresponds to the lower horizontal part of the L-shaped position regulating member 27, and the left and right heat insulating plates 21 and 22 are formed in a flat plate shape, and have a rectangular tubular shape as a whole. The light source storage part 29 is formed. The upper heat insulating plate 19 is provided with a cut-and-raised portion 19a inclined along the outer peripheral surface of the light source unit 14 and an opening 19b corresponding to the cut-and-raised portion 19a. The left heat insulating plate 21 has three fan-shaped openings 21 a formed at locations corresponding to the light source section 14.
A filter 30 that absorbs infrared rays is provided outside the light source storage portion 29 and in front of the opening 28a of the position regulating portion 28 (on the right side in FIG. 8). Further, as shown in FIG. 11, a cooling fan 17 is arranged outside the light source storage portion 29 so as to face the opening 21 a of the left heat insulating plate 21. The cooling fan 17 introduces cool external air into the light source storage portion 29 through a fan ventilation hole 31 formed on the left side surface of the unit case 7, and discharges warm air inside the light source storage portion 29 through the ventilation hole 18a. Therefore, the light source unit 14
Is for cooling.

Further, as shown in FIG. 6, the electric circuit portion is composed of three circuit portions, that is, a filter circuit 32, a voltage conversion circuit 33, and a fan control circuit 34, which are separately mounted in the unit case 7. The filter circuit 32 is for removing the noise component of the supplied AC power supply and supplying it to the voltage conversion circuit 33, and is mounted on the circuit board 35 arranged in the front right half of the unit case 7. The voltage conversion circuit 33 is for lowering the voltage of the AC power supply supplied from the filter circuit 32 and supplying it to the light source 14 and the fan control circuit 34, and is arranged in the left half portion on the inner side in the unit case 7. The fan control circuit 34, which is mounted on the circuit board 36, converts the AC power supplied from the voltage conversion circuit 33 into a DC power and supplies the DC power to the cooling fan 17. It is mounted on the circuit board 37 arranged in half. In addition, each circuit board 35
To 37 are detachably arranged in the unit case 7. A socket 38, which is a port for taking in the AC power, is provided at the front left end of the unit case 7.

As shown in FIGS. 1 and 6, the lower surface of the unit case 7 is provided with a power switch 39 at the other end (the right end in the figure). This power switch 39
As shown in FIG. 12, after accommodating the stage base 2 in the arm portion 3, when the projection unit 1 is accommodated, it is erected at one end portion (the left end portion in FIG. 2) on the lower surface of the stage base 2. It is adapted to be pressed by the boss 40.
In this case, as shown in FIG.
9 is in the ON state, the power switch 39 is the boss 40
By being pressed by, it is turned off as shown in FIG.

As shown in FIG. 1, a concave portion 7a is formed on the upper surface of the unit case 7 on the other end side (the right end side in FIG. 1) over the tip surface. The projection lens 16 is movably arranged along the optical axis of the projection lens 16 in a state corresponding to the recess 7a in the unit case 7 while being exposed from the bottom surface of the recess 7a. In addition, the projection lens 1 is placed in the unit case 7 at a location corresponding to the recess 7a.
A focus adjusting knob 41 for adjusting the focal position of the projection lens 16 by moving 6 along its optical axis is provided with a part thereof protruding from the concave portion 7a toward the tip surface.

The concave portion 7a of the unit case 7 is shown in FIG.
As shown in, the projection mirror 43 is provided on the lower surface of the lid 42 facing the projection lens 16. The lid 42 is attached so that it can be erected sideways by its standing sideways mechanism and its angle can be adjusted by its angle adjusting mechanism. In the standing upside down mechanism, moving shafts 44 are provided on both sides of one end (lower end on the left side in FIG. 14) of the lid 42 so as to project laterally, and the moving shafts 44 are provided on the inner side of the facing surface in the recess 7a. It is movably inserted in the guide groove 45, one end (upper end in FIG. 14) of the support lever 46 is rotatably attached to the middle of the side surface, and the other end (lower end in FIG. 14) of the support lever 46.
The elongated hole 46a provided in the above is rotatably inserted into the fixed shaft 47 projecting from the facing surface in the recess 7a on the front side (right side in FIG. 14) of the guide groove 45.
Further, a locking portion 48 is provided at one end portion (right end portion in FIG. 14) of the guide groove 45. The angle adjustment mechanism is shown in FIG.
As shown in FIG. 5, an elastic member 49 such as a rubber packing is interposed between the support lever 46 and the facing surface in the recess 7a. In addition, 50 is a nylon washer for improving the sliding of the support lever 46. And
As shown in FIG. 14, the lid body 42 is arranged so that the support lever 46 rotates around the other end of the support lever 46, and the moving shaft 44 moves in the guide groove 45 so that the lid body 42 rises and falls sideways in the recess 7 a. It has become. Therefore, when the lid 42 is stored in the concave portion 7a while lying sideways, the projection lens 16
The movable shaft 44 is locked by the locking portion 48 of the guide groove 45 in the upright state, and is supported by the support lever 46 while being inclined at a predetermined angle. Also, the lid 42
Is moved up and down by sliding the support lever 43 up and down, and the standing angle of the projection mirror 15 is finely adjusted.

By the way, as shown in FIGS. 16 and 18, the lower end of the arm portion 3 locks the projection unit 1 with respect to the arm portion 3 at the time of storage, and the stage base 2 with respect to the arm portion 3 during use. Locking mechanism 51
Is provided. This locking mechanism 51 is shown in FIG.
As shown in (A) and FIG. 19 (A), a pair of lock pins 52 having a substantially L-shape having a locking portion 52a provided at one end and an operation portion 52b provided at the other end, and elasticity of a coil spring or the like. And a member 53. Each lock pin 52 is slidably arranged in a long hole 54 formed at the lower end of the arm portion 3 with one end protruding from the lower inner surface of the arm portion 3. The elastic member 53 is arranged between the arm portion 3 and the lock pin 52 and biases in the locking direction. In this lock mechanism 51, when the stage base 2 projects horizontally from the arm portion 3, the locking portion 52a of the lock pin 52 slid by the elastic force of the elastic member 53 is used.
17A, the lock pin 52 is inserted into the locking recess 55 provided on the lower surface 2a of the stage base 2 to lock the stage base 2, and the lock pin 52 protruding outside the arm portion 3.
17B is slid against the elastic force of the elastic member 53 to disengage the locking portion 52a from the locking recess 55 of the stage base 2 as shown in FIG. unlock. On the other hand, when the stage base 2 and the projection unit 1 are stored in the arm portion 3, the locking portion 52a of the lock pin 52 slid by the elastic force of the elastic member 53 is stored in the projection unit as shown in FIG. 1 is inserted into a locking recess 56 provided on the lower surface of the projection unit 1 to lock the projection unit 1, and the operating portion 52b of the lock pin 52 protruding from the lower end portion of the arm portion 3 is attached to the elastic member 53 in the arrow direction of FIG. By sliding against the elastic force, the locking portion 52a is disengaged from the locking concave portion 56 of the projection unit 1 and the projection unit 1 is unlocked, as shown in FIG.

Next, FIG. 21 shows the optical path of this portable overhead projector and each optical element on the optical path.
This will be described with reference to FIG. In the light source unit 14 arranged in the projection unit 1, the light source 14a is arranged at or near the focal position of the reflector 14b, and the light of the light source 14a is filtered by the reflector 14b at the front (not shown in FIG. 21).
The light is condensed on the side of the total reflection mirror 15 via 30. In this case, the light source 14a is, for example, 75 V at 12V.
W. The reflecting surface of the reflector 14b is formed in a shape having a focal length fR of about 43 mm, and is formed of a dichroic mirror that transmits infrared rays and reflects other light in order to reduce heating due to heat generation of the light source 14a. Has been done. The filter 30 blocks infrared rays and transmits other light. Total reflection mirror 15
In order to reflect the light condensed by the reflector 14b toward the Fresnel mirror 8 of the stage base 2, the light source unit 1
The optical axis 61 of 4 is inclined by a predetermined angle.
In this case, from the optical axis 61 of the light source unit 14 to the Fresnel mirror 8
The distance L1 to the upper surface of is set to about 183 mm.

The Fresnel mirror 8 is for focusing incident light on the projection lens 16 of the projection unit 1,
As shown in FIG. 22, a Fresnel lens 8a having a flat upper surface and a lower Fresnel surface is integrally formed with a reflecting surface 8b by aluminum sputtering on the lower Fresnel surface. The Fresnel lens 8a is made of an acrylic sheet and has a thickness of 1 mm or less. The total thickness t1 is preferably about 0.4 mm, the lens cut thickness t1 is about 0.2 mm, and the Fresnel ring pitch is about 0.2 mm. p is formed to be about 0.35 mm. The size of the Fresnel mirror 8 is 95 ± 10 × 95 ±
10 mm. Further, as shown in FIG. 21, the angle θ with respect to the direction of the incident light 62 on the upper surface of the Fresnel mirror 8 is increased.
1 and the angle θ2 with respect to the direction of the outgoing light 63 on the upper surface of the Fresnel mirror 8 are different. Further, the angle θ3 formed by the incident light 62 and the outgoing light 63 on the upper surface of the Fresnel mirror 8 is from the optical axis 61 of the light source unit 14 to the Fresnel mirror 8 even if the total reflection mirror 15 and the projection lens 16 are closest to each other.
Since the distance L1 to the upper surface of is as short as approximately 183 mm, 14
It is set to about °. Further, the reflecting surface of the Fresnel mirror 8 is formed as an aspherical surface having a smaller radius of curvature in the peripheral portion than in the central portion. For example, as shown in the principle diagram of FIG. 23, the focal length of the central portion is 100 mm, and the focal length of the peripheral portion is an aspherical surface whose curvature changes within a range of 93 mm. Further, this aspherical surface is represented by the following general formula. Z = (1 / R) · L ² / [1-√ {1- (A ₂ +1) ・
(1 / R ² ) · L ² }] + A ₄ L ⁴ + A ₆ L ⁶ where Z is the amount of displacement (displacement) at the distance L from the lens center, R is the paraxial radius of curvature, and A is the aspherical coefficient. is there. Further, as shown in FIG. 24, the center of the Fresnel mirror 8 is displaced from the light source unit 14 side toward the projection lens 16 side, and the light from the light source unit 14 can be sufficiently incident on the projection lens 16. And the deviation amount Δd
Is about 5 to 10 mm. As a result, the angle θ1 with respect to the direction of the incident light 62 on the upper surface of the Fresnel mirror 8 and the angle θ2 with respect to the direction of the emitted light 63 on the upper surface of the Fresnel mirror 8 are different.

The projection lens 16 is, as shown in FIG.
The image of the image projection sheet 9 placed on the Fresnel mirror 8 is enlarged and projected onto a screen (not shown) via the projection mirror 43 of the lid 42, and the focal length f2
Is about 165 mm, the F number is about 3.5, the projection distance is 1.5 to 3.0 m, the magnification is 7 to 15.0 times,
The distance from the projection lens 16 to the upper surface of the Fresnel mirror 8 is set to 147 to 160 mm. The lid 4
The second projection mirror 43 is supported in the concave portion 7a of the unit case 7 while being inclined at a predetermined angle such that the optical axis 64 of the reflected light is slightly upward from the horizontal.

By the way, the transparent image projection sheet 9 placed on the Fresnel mirror 8 of the stage base 2 is shown in FIG.
As shown in FIG. 7, the image information is formed into a predetermined size (D ₁ × D ₂ mm) that can be printed by a printer or a copying machine, and the size of the specified size after printing (D ₃ × D ₄ mm).
A perforation 65 for cutting is formed. On one side in the longitudinal direction of the image projection sheet 9, a plurality of binder holes 66 are formed at substantially equal intervals, and perforations 67 are formed from the binder holes 66 to the end sides. ing. The perforations 67 are for attaching and detaching the image projection sheet 9 as it is without opening the binder. Here, showing specific numerical values, the predetermined size is the postcard size (D ₁ = 148 mm, D ₂
= 100 mm), the designated size is formed to be a notebook size (D ₃ = 127 mm, D ₄ = 80 mm). When the predetermined size is about COM-10 size (D ₁ = 241 mm, D ₂ = 105 mm), the specified size is the notebook size (D ₃ = 184 mm, D _4).
= 80 mm).

As described above, in such a portable overhead projector, the printer or the copying machine forms the image information into a printable size, and after printing, cuts it into the size of the designated size such as the notebook size. Since the perforations 65 are formed, even if the image creating sheet 9 is reduced to the size of a notebook, it does not require a special device such as a photographic method, and the image creating sheet 9 is created by an existing personal computer or word processor. To easily and easily create an image projection sheet 9 of about the size of a notebook or smaller by printing the information such as a document or an image with a printer or reducing and copying it with a copying machine. You can Therefore, by using the image projection sheet 9 of the size of the notebook, it is possible to form the stage base 2 in the size of the notebook, for example, in the Bible size of B6 size. The arm portion 3 can also be formed to have substantially the same size as that of the stage base 2, whereby the size and weight of the entire apparatus can be significantly reduced.

Further, in this portable overhead projector, the light source unit 14, the projection lens 16, the cooling fan 17, and the electric circuit unit are provided in the projection unit 1, and the electric circuit unit is provided with the filter circuit 32, the voltage conversion circuit 33, and the like. Since it is mounted in the projection unit 1 by dividing it according to the circuit function such as the fan control circuit 34 that drives and controls the cooling fan, each circuit can be mounted in a distributed manner in the gap in the projection unit 1. The packaging density can be increased by this, the overall size and weight of the device can be greatly reduced, and the one with excellent portability can be obtained. Moreover, the devices are distributed and mounted according to the circuit function. Therefore, when replacing the electric circuit, it is not necessary to replace the entire electric circuit, and only the necessary circuit can be replaced.

Further, in this portable overhead projector, since the projection unit 1 and the stage base 2 are rotatably attached to the arm portion 3 by the support shafts 5 and 6, respectively, the projection unit 1 and the stage base 2 are armed. It can be folded and stored in the part 3. In this case, first, the lock of the arm part 3 by the lock mechanism 51 is released, and the stage base 2 is rotated around the stage base side support shaft 5 as shown in FIG. Then, the projection unit 1 is rotated about the projection unit side support shaft 6, and the projection unit 1 is folded and stored in the arm portion 3 while being superimposed on the stage base 2 as shown in FIG. , The lock mechanism 51 of the arm 3 locks. This makes the entire device compact. At this time, since the arm portion 3 has a B6 size of B6 size, the entire folded size becomes a B6 size of B6 size. For this reason, a salesperson can easily carry it in a bag or a bag and obtain a highly portable product. Further, since the projection unit 1 is locked to the arm portion 3 at the time of storage, and the stage base 2 is locked to the arm portion 3 at the time of use, a lock mechanism 51 is provided. The projection unit 1 or the stage base 2 with respect to the arm portion 3 at each time can be surely locked as needed, and the number of the lock mechanisms 51 can be reduced, whereby the number of parts can be reduced. Further, when the projection unit 1 is housed in the arm portion 3, the power supply switch 39 is turned off and cuts off the power supply to the electric circuit portion. Can be reliably prevented from being heated, and a highly safe product can be obtained.

When such a portable overhead projector is used, contrary to the above operation, first, the projection unit 1 is rotated so that a part of the projection unit 1 is horizontally projected from the arm unit 3, and then the stage is mounted. The table 2 is rotated so that a part of the table 2 is horizontally projected from the arm portion 3. In this state, the stage table 2 is locked to the arm portion 3 by the lock mechanism 51, and the stage table 2 and the arm portion 3 are mounted on a table. After being placed, the lid 42 of the projection unit 1 is raised and supported by the support lever 46 at a predetermined angle shown in FIG. Then, the image projection sheet 9 is placed on the Fresnel mirror 8 of the stage table 2 and is pressed by the transparent sheet pressing plate 10. The sheet pressing plate 10 has a shaft portion 1 having a rectangular cross section at both ends.
1 is provided so as to project, and a bearing portion 12 on which a shaft portion 11 is rotatably mounted is provided on a stage base 2 on the side connected to the arm portion 3. The bearing portion 12 has a sectional shape of the shaft portion 11. Since the insertion groove 13 having a width corresponding to the short side is provided toward the side connected to the arm portion 3, the insertion groove 13 of the bearing portion 12 is provided before the stage base 2 is connected to the arm portion 3. The shaft portion 11 can be easily inserted from the above to be mounted on the bearing portion 12, and even when the shaft portion 11 is taken out from the insertion groove 13 when the stage base 2 is connected to the arm portion 3, the seat pressing plate 10 is Since the shaft portion 11 comes into contact with the arm portion 3, the shaft portion 11 does not come off from the bearing portion 12. Therefore, the image projection sheet 9 can be reliably pressed. Also,
Since the transparent sheet pressing plate 10 for pressing the image projecting sheet 9 which is the original is rotatably provided on the stage table 2,
At the time of use, it is possible to prevent the image projection sheet 9 from curling due to heat from the light source unit 14 or the habit of the image projection sheet 9 itself, and it is possible to project a good image without distortion.

In this state, the light source 14a of the light source section 14 is turned on. Then, as shown in FIG. 21, the light from the light source 14 a is condensed by the reflector 14 b and is reflected by the total reflection mirror 15.
Is totally reflected by the image projecting sheet 9. FIG. 26A shows a part of the light emitted to the image projection sheet 9.
As shown in FIG.
The light, which is blocked by and is irradiated to the other portion, passes through the image projection sheet 9 and enters the Fresnel mirror 8. This incident light is reflected by the Fresnel mirror 8 as shown in FIG.
Of the reflected light reflected by the reflecting surface 8b of the image part 9
The light that reaches a is blocked by the image portion 9a, and the reflected light that reaches the other portions passes through the image projection sheet 9 and is condensed by the Fresnel mirror 8 on the projection lens 16. As a result, the image of the image projection sheet 9 is enlarged and projected as a projection image on the screen by the projection lens 16 via the projection mirror 43 of the lid 42. Further, the projection mirror 43 can be erected at a predetermined angle by the erection sideways mechanism simply by erecting the projection mirror 43.
The upright angle of 3 can be finely adjusted by the angle adjusting mechanism, whereby the projected image can be reliably and satisfactorily projected at a desired position.

Further, in this portable overhead projector, the light source section 14 is detachably attached to the socket 24 provided through the elastic member 23 on the light source opening / closing lid 18 provided in the projection unit 1 to open / close the light source. Lid 1
Since 8 is rotatably provided around a support shaft 25 that is movably attached to the projection unit 1, by rotating and opening the light source opening / closing lid 18 about the support shaft 25, The light source unit 14 can be easily attached and detached, and after the light source unit 14 is attached to the light source opening / closing cover 18, when the light source opening / closing cover 18 is rotated in the closing direction, or after the support shaft 25 is rotated. By shifting, the peripheral portion of the front surface of the reflector 14b can be reliably pressed against the position restricting portion 28 of the projection unit 1 by the elastic force of the elastic member 23, and thereby the optical axis 61 of the light source 14a can be positioned uniformly. Therefore, the light source unit 14 can be attached and replaced very easily.

Further, heat insulating plates 19 to 22 for blocking radiant heat from the light source unit 14 are provided around the light source unit 14, and the heat insulating plate 1 is provided.
9 is a cut-and-raised portion 19a inclined along the outer peripheral surface of the light source portion 14.
Is provided corresponding to the light source opening / closing lid 18, the light source unit 14
It is possible to prevent parts such as the electric circuit portion and the light source opening / closing lid 18 provided around the heat source from being heated by the radiant heat from the light source portion 14, and the cut-and-raised portion 19a is provided on the heat insulating plate 19 for the light source opening / closing lid. Since the openings 19b corresponding to the cut-and-raised portions 19a are formed in the heat insulating plate 19 by being provided corresponding to 18, the air heated by the light source unit 14 is passed through the openings 19b of the heat insulating plate 19 to form the light source. It is possible to discharge the light from the vent hole 18a of the opening / closing lid 18 for the outside, and the light source unit 14 can be cooled efficiently. In addition, the light source unit 14 is provided in the light source storage unit 29 arranged in the unit case 7.
Since the cooling fan 17 forcibly introduces the external cool air into the light source housing portion 29, the light source portion 14 can be reliably cooled, and thus the light source 14
It is possible to prevent the unit case 7 from being thermally deformed by heating due to the heat generated by a, and since the heat insulating plates 19 to 22 forming the light source housing 29 are made of metal, the light source 14a can be strongly protected. In addition to being able to perform, it can also serve to reinforce the unit case 7.

By the way, in this portable overhead projector, when the light applied to the image projection sheet 9 is focused on the projection lens 16 by the Fresnel mirror 8, from the optical axis 61 of the light source 14a to the upper surface of the Fresnel mirror 8. Since the distance L1 is about 183 mm, the angle θ3 between the incident light and the outgoing light on the optical axis on the upper surface of the Fresnel mirror 8 is about 14 ° even if the total reflection mirror 15 and the projection lens 16 are brought close to each other to a minimum. Although the size of the Fresnel mirror 8 is increased, the thickness of the Fresnel mirror 8 is formed as thin as 1 mm or less. Therefore, a good projection image can be obtained for the following reasons.

In the conventional device, since the outer shape of the entire device is large, the distance L1 from the optical axis 61 of the light source 14a to the surface of the Fresnel mirror 8 can be set long, so that the total reflection mirror 15 and the projection lens 16 are separated from each other. If the distance is constant,
The angle θ3 formed by the incident light and the outgoing light on the upper surface of the Fresnel mirror 8 is as small as about 5 to 7 °. Therefore, even if the Fresnel mirror 8 is thick, the deviation of the projected image in the vertical direction is hardly noticeable. However, when the size of the entire apparatus is reduced as in this embodiment, the distance L1 from the optical axis 61 of the light source 14a to the upper surface of the Fresnel mirror 8 is shortened to about 183 mm, so that the incident light and the emitted light on the upper surface of the Fresnel mirror 8 are reduced. The angle θ3 formed by and becomes large at about 14 °.
For this reason, when the Fresnel mirror 8 is thick, the deviation of the projected image in the vertical direction becomes noticeable as follows.

That is, when the Fresnel mirror 8 is thick, the image portion 9a of the image projection sheet 9 and the reflecting surface 8b of the Fresnel mirror 8 are separated from each other as shown in FIG. Part of the light emitted from the image projection sheet 9 from the image projection sheet 15 is part of the image portion 9 of the image projection sheet 9.
The first projection image 9b is produced at the position shown by the solid line in the figure by the reflection surface that is blocked by a, and the light reflected by the image portion 9a that has reached the reflection surface without being blocked is part of the image. The second projection image 9c is created at the position shown by the dotted line in the figure by being blocked by the image portion 9a of the projection sheet 9. Since the first and second projection images 9b and 9c are apart without overlapping, the projection image projected by the projection lens 16 is a double image in which the first and second projection images 9b and 9c are vertically displaced. become. However, when the thickness of the Fresnel mirror 8 is reduced to about 1 mm or less as in this embodiment, the image portion 9a of the image projection sheet 9 and the Fresnel mirror 8 are formed as shown in FIG. Since the reflecting surface 8b approaches, the total reflection mirror 1
The first projected image 9b by the light radiated from the image projection sheet 9 from 5 is produced at the position shown by the solid line in the figure, and is also reflected by the light reaching the reflecting surface without being blocked by the image portion 9a. The second projected image 9c is created at the position shown by the dotted line in the figure, and the first and second projected images 9b and 9c are substantially displaced from each other and substantially overlap each other. Therefore, even when the image is enlarged and projected on the screen, the first and second projected images 9b and 9c can be visually recognized as a unit, and a clear projected image can be obtained.

Further, as shown in FIG. 23, since the reflecting surface 8b of the Fresnel mirror 8 is formed to be an aspherical surface having a smaller radius of curvature in the peripheral portion than in the central portion, the Fresnel mirror 8 is irradiated with light from the light source portion 14. Of the light, the light in the peripheral portion can be reliably focused on the projection lens 16, which improves the utilization efficiency of the light, prevents a decrease in the illuminance in the peripheral portion of the projected image, and provides a substantially uniform brightness. The projection image can be obtained, and the light from the light source unit 14 is reflected by the Fresnel mirror 8 and condensed on the projection lens 16. Therefore, the optical path length from the light source unit 14 to the projection lens 16 is sufficient. Can be secured. Further, as shown in FIG. 24, the center of the Fresnel mirror 8 is deviated from the light source unit 14 side toward the projection lens 16 side by Δd.
The light from 4 can be sufficiently incident on the projection lens 16, and the brightness of the entire projected image can be improved.

The Fresnel mirror 8 of the above embodiment is used.
Has a total thickness t1 of about 0.4 mm, a lens cut thickness t2 of about 0.2 mm, and a Fresnel ring pitch p of 0.35.
The Fresnel ring 8 is formed to have a thickness of about 0.1 mm, but the total thickness t1 of the Fresnel mirror 8 can be reduced to 0.4 mm or less as the pitch p of the Fresnel ring is reduced to 0.35 mm or less. In this way, the optical axis 6 of the light source 14a
Even if the distance L1 from 1 to the Fresnel mirror 8 is shorter than that in the above-described embodiment, the deviation of the projected image can be suppressed,
The size of the entire apparatus can be further reduced. Further, in the Fresnel mirror 8 of the above embodiment, the reflecting surface 8b is integrally formed on the lower surface of the Fresnel mirror 8 by sputtering aluminum, but it is not always necessary to integrally form the reflecting surface 8b, and the reflecting plate is provided below the Fresnel lens 8a. It may be a structure that is arranged. Further, in the above-described embodiment, the light from the light source 14a is reflected by the total reflection mirror 15 toward the Fresnel mirror 8, but the light from the light source 14a may be directly condensed and emitted. good. Furthermore, in the above embodiment, when the image of the image projection sheet 9 is enlarged and projected by the projection lens 16, the projection mirror 43 of the lid 42 changes the projection direction, but the projection mirror 43 does not necessarily change the projection direction. There is no need to change it. For example, by placing the arm unit 3 on a table so that the projection unit 1 and the stage base 2 stand vertically, the projection lens 16 may directly perform enlarged projection on the screen. good.

[0044]

As described above, according to the invention described in claim 8, image information is printed by a printer or a copying machine on an image projection sheet placed on a stage table and held by a sheet holding plate. Formed to the size possible
Moreover, since perforations are formed for cutting into a specified size, such as a notebook size after printing, it does not require a special device such as a photographic method, and can be created on an image creation sheet using an existing personal computer or word processor. Information such as printed documents and images can be printed with a printer, or a printed copy can be reduced and copied with a copier, and the printed image projection sheet can be cut at perforations, making it simple and easy. It is possible to create an image projection sheet that is about the size of a notebook, and this makes it possible to form the stage table to the size of the notebook, which greatly reduces the size and weight of the entire device. It will be possible.

According to the first aspect of the present invention, the projection unit and the stage base are foldably connected to each other via the arm section, and the light source section, the projection lens, and the electric circuit section are provided in the projection unit. Since this electric circuit section is divided and mounted in the projection unit according to the circuit function of the filter circuit, voltage conversion circuit, etc., it is possible to disperse and mount each circuit in the gap in the projection unit. Since the density can be increased, the size and weight of the entire device can be greatly reduced, and the device with excellent portability can be obtained, and the devices are distributed and mounted according to the circuit function. When replacing the electric circuit, it is not necessary to replace the entire electric circuit, and only the necessary circuit can be replaced.

According to the invention described in claim 9, it is provided with a projection unit provided with a light source section and a projection lens, and a stage base provided with a reflection plate for reflecting light from the light source section toward the projection lens. In the portable overhead projector, the light source unit includes a light source and a reflector that reflects light from the light source, and is detachably attached to the projection unit via an elastic member and is displaceably attached in any direction, Since the peripheral portion of the front surface of the reflector is positioned by being pressed against the position regulating member of the projection unit by the elastic force of the elastic member, the peripheral portion of the front surface of the reflector can be positioned at the position of the projection unit even if the outer dimensions of the light source unit vary. By pressing the elastic member against the regulating member by the elastic force, the optical axis can be made constant, and therefore the light source section With and exchange easy, can be obtained as a user-friendly.

According to the thirteenth aspect of the present invention, in the portable overhead projector that reflects the light from the light source section by the Fresnel mirror and focuses it on the projection lens, the reflecting surface of the Fresnel mirror is located in the peripheral portion rather than the central portion. Since it is formed on an aspherical surface with a small radius of curvature, of the light emitted from the light source to the Fresnel mirror, the peripheral light can be reliably focused on the projection lens, which improves the light utilization efficiency. However, it is possible to prevent the illuminance from decreasing in the peripheral part of the projected image and obtain a projected image with almost uniform brightness over the entire area, and also to reflect the light from the light source part with a Fresnel mirror and focus it on the projection lens. Therefore, the optical path length from the light source unit to the projection lens can be sufficiently secured.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of a portable overhead projector of the present invention in a use state.

FIG. 2 is a side view showing the folding process of FIG. 1 in a state where the stage base is folded in the arm portion.

FIG. 3 is a side view showing a folding process subsequent to FIG. 2, showing a state in which the projection unit is folded into the arm portion in which the stage base is housed.

FIG. 4 is a perspective view showing a mounting structure of the sheet pressing plate of FIG.

5A is a perspective view showing the bearing portion of FIG. 4, and FIG. 5B is a side view showing a state in which the shaft portion is inserted into the bearing portion.

6 is a plan view showing the inside of the projection unit of FIG. 1. FIG.

FIG. 7 is a side view showing a mounting structure of the light source unit of FIG.

8 is a perspective view showing a heat insulating plate provided around the light source unit of FIG.

9A is a plan view showing a mounting structure of a socket to which the light source unit of FIG. 7 is mounted, and FIG. 9B is a side view thereof.

10A is a side view of the light source opening / closing lid of FIG. 7 being closed, and FIG. 10B is a side view of the light source opening / closing lid being opened.

11 is a cross-sectional view showing how the light source unit of FIG. 7 is cooled.

FIG. 12 is a side view, partly in section, showing a power switch that is turned off when the projection unit of FIG. 1 is housed in an arm portion.

13A and 13B are diagrams showing a process in which the power switch of FIG. 12 is turned off.

14 is a side view showing an attachment structure of a lid body provided with the projection mirror of FIG.

FIG. 15 is a sectional view showing the attachment structure of the lid.

FIG. 16 is a view showing a state of a lock mechanism in a use state of the portable overhead projector.

17A is a cross-sectional view showing a locked state of the lock mechanism of FIG. 16, and FIG. 17B is a cross-sectional view showing a released state of the lock mechanism.

FIG. 18 is a plan view showing a state of the lock mechanism in the housed state of the portable overhead projector.

19A is a cross-sectional view showing a locked state of the lock mechanism of FIG. 18, and FIG. 19B is a cross-sectional view showing a released state of the lock mechanism.

20 is a front view showing the lock mechanism of FIG. 18. FIG.

FIG. 21 is a diagram showing the optical path of FIG. 1 and an optical element on the optical path.

22 is an enlarged sectional view of the Fresnel mirror shown in FIGS. 1 and 21. FIG.

FIG. 23 is a diagram showing that the Fresnel mirrors of FIGS. 1 and 21 are aspherical surfaces.

FIG. 24 is a diagram showing that the center of the Fresnel mirror in FIGS. 1 and 21 is displaced toward the projection lens side.

FIG. 25 is a plan view showing the image projection sheet of FIG. 21.

FIG. 26 shows an optical path state in a Fresnel mirror, (A)
Is an enlarged view showing an optical path state when using a thin Fresnel mirror in this embodiment, and FIG. 6B is an enlarged view showing an optical path state when using a conventional thick Fresnel mirror.

[Explanation of symbols]

 1 Projection Unit 2 Stage Stage 3 Arms 5 and 6 Support Axis 7 Unit Case 8 Fresnel Mirror (Reflector) 9 Image Projection Sheet 10 Sheet Pressing Plate 14 Light Source 16 Projection Lens 17 Cooling Fan 32 Filter Circuit 33 Voltage Conversion Circuit 34 Fan control circuit 39 Power switch 51 Lock mechanism

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Annori 32-1 Sakaemachi, Hamura-shi, Tokyo Casio Computer Co., Ltd. Hamura Technical Center

Claims (14)

[Claims] 1. A portable overhead projector for use in a state in which a projection unit and a stage base are foldably connected via an arm portion, and the projection unit is held facing the stage base by the arm portion. A light source unit, a projection lens, and an electric circuit unit are provided in the projection unit, and the electric circuit unit is a filter circuit,
A portable overhead projector, characterized in that the portable overhead projector is divided and mounted according to the circuit function of a voltage conversion circuit or the like in the projection unit. 2. A cooling fan is provided in the projection unit in addition to the light source section, the projection lens, and the electric circuit section, and the electric circuit section includes the filter circuit.
2. The portable overhead projector according to claim 1, wherein, in addition to the voltage conversion circuit, a fan control circuit that drives and controls the cooling fan is separately mounted. 3. The portable overhead projector according to claim 1, wherein the arm unit has a structure in which the projection unit and the stage base are folded and housed. 4. A lock mechanism for fixing the projection unit to the arm portion during storage and for fixing the stage base to the arm portion at the time of use. Portable overhead projector. 5. The power supply switch according to claim 1, further comprising a power switch that is turned off when the projection unit is housed in the arm portion and cuts off power to the electric circuit portion. A portable overhead projector as described in. 6. The mobile phone according to claim 1, wherein the stage base is rotatably provided with a transparent sheet pressing plate for pressing an image projection sheet which is a document. Type overhead projector. 7. The sheet pressing plate is provided at both ends with a shaft portion having a rectangular cross section, and the shaft portion is rotatably mounted on the stage base on the side connected to the arm portion. A bearing portion is provided, and the bearing portion is provided with an insertion groove having a width corresponding to a short side of a cross-sectional shape of the shaft portion, the insertion groove being provided toward a side connected to the arm portion. 6. The portable overhead projector according to item 6. 8. The image projection sheet placed on the stage table and held by the sheet holding plate,
7. The image information is formed in a printable size by a printer or a copying machine, and perforations are formed for cutting the image information into a size of a designated size such as a notebook size after printing. 7. The portable overhead projector according to 7. 9. A portable overhead projector comprising: a projection unit provided with a light source section and a projection lens; and a stage base provided with a reflection plate for reflecting light from the light source section toward the projection lens. The light source unit includes a light source and a reflector that reflects light from the light source, is detachably attached to the projection unit via an elastic member, and is movably attached in any direction. The portable overhead projector is characterized in that the peripheral portion of the front surface is positioned by being pressed against the position regulating member of the projection unit by the elastic force of the elastic member. 10. The light source unit is detachably attached to a light source opening / closing lid provided in the projection unit via the elastic member, and the light source opening / closing lid is movably attached to the projection unit. The portable overhead projector according to claim 9, wherein the portable overhead projector is provided so as to be rotatable around a support shaft. 11. A heat insulating plate that blocks radiant heat from the light source unit is provided around the light source unit, and the heat insulating plate has a cut-and-raised portion that is inclined along an outer peripheral surface of the light source unit. The portable overhead projector according to claim 10, wherein the portable overhead projector is provided so as to correspond to an opening / closing lid. 12. The projection unit includes a projection mirror that reflects the projection light from the projection lens, a standing upside down mechanism that raises the projection mirror at a predetermined angle, and a standing upside down mechanism that stands up at a predetermined angle. The portable overhead projector according to claim 1 or 9, further comprising an angle adjusting mechanism for finely adjusting an upright angle of the projection mirror. 13. A portable overhead projector that reflects light from a light source section by a Fresnel mirror and focuses it on a projection lens, wherein the reflection surface of the Fresnel mirror has a radius of curvature that is smaller in the peripheral portion than in the central portion. A portable overhead projector characterized by being formed into a spherical surface. 14. The portable overhead projector according to claim 13, wherein the center of the Fresnel mirror is displaced from the light source unit side toward the projection lens side.