JP2709493B2 - Overhead projector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an overhead projector (hereinafter abbreviated as “OHP”), and more particularly to an OHP which is of a light transmission type and can be folded small when not in use. It is.

(Prior Art) There are two types of OHP, a transmission type and a reflection type, each of which has advantages and disadvantages. For example, The reflection type OHP can take the optical path from the light source to the document outside the device, so it is easy to reduce the size when storing it.
On the other hand, in the transmission type OHP, the optical path from the light source to the document must be set in the apparatus, and it is difficult to reduce the size.

It is for the following reasons. That is, generally, a light source is disposed directly below the Fresnel lens so as to oppose the Fresnel lens, so that light is directly applied to a document placed on the Fresnel lens. Therefore, if the light source is brought closer to the Fresnel lens, the distance of the optical path in the device will be shorter and miniaturization can be achieved.However, if the light source is closer to the Fresnel lens, the center of the document surface will be brighter and the surrounding area will be brighter. It becomes dark and the uniformity of brightness is impaired. In general, if the distance between the light source and the Fresnel lens is l ₁ and the distance between the Fresnel lens and the projection lens is l ₂ , the focal length f of the Fresnel lens becomes Therefore, even if the light source is brought closer to the Fresnel lens by improving the reflector, uniform brightness can be obtained, but if l ₁ is shortened, the focal length of the Fresnel lens must also be shortened. Therefore, a Fresnel lens that can cover a large document size cannot be made.

For the above-mentioned reasons, it is a light transmission type OHP which is difficult to miniaturize, and the need to reduce the size of the storage so that it is easy to carry is demanded as described above, which is an advantage not found in the reflection type. Because.

Conventional light transmission type OHPs generally have a Fresnel lens arranged on the top of the OHP body or a lamp of a light source arranged so as to face the lower surface of a stage on which a document is placed, and are emitted from the lamp and passed through the Fresnel lens. In order to receive light, a projection lens and a projection mirror are arranged at the upper end of a pole or arm rising from the main body.

In order to reduce the size, various types of devices having a structure such as folding of an arm when not in use have been proposed. For example, in Japanese Patent Publication No. 51-2246, a pole holding a projection head and standing up from a main body case is laid down when not in use and stored together with the head in the case, and the stage surface is lowered. It has become. Also, those described in Japanese Utility Model Publication No. 60-4174,
When not in use, the stage is once opened, the head support rod rising from one corner of the main body is lowered into the main body case and stored together with the head, and then the stage is covered with the lid. Further, as a type in which the head portion is folded down and accommodated in the main body case, there are ones described in Japanese Utility Model Publication No. 60-2585 and Japanese Utility Model Application Laid-Open No. 57-39041.

(Problems to be Solved by the Invention) However, all of the above-mentioned conventional examples are of the type in which the head portion is housed in the main body case together with the support arm, so that the space factor is not good, and therefore, it is sufficiently small. The effect of conversion was not obtained.

The present invention solves the above-mentioned problems of the prior art,
It is an object of the present invention to provide an OHP capable of improving a space factor and achieving sufficient miniaturization.

(Means for Solving the Problems) In order to achieve the above object, the present invention has a mirror between a light source and a Fresnel lens, and furthermore, at the time of storage, the projection head and its supporting member of the OHP body. It is stored so that it contacts the top, side, and bottom surfaces, respectively.

(Operation) According to the achievement of the present invention, the mirror provided between the light source and the Fresnel lens partially projects from the bottom surface of the main body at the time of projection, but is stored inside the main body at the time of storage. Since the projection head and its supporting member are housed so as to surround the outer surface of the OHP main body, the space factor becomes very good and a sufficient miniaturization is achieved.

(Example) Hereinafter, an Example is described in detail with reference to drawings. First
FIGS. 2 and 3 show an OHP according to a first embodiment of the present invention. FIG.
The figure shows the state at the time of storage. 3 and 4
The figure is a perspective view in each state. 1 to 4
In the drawing, reference numeral 1 denotes an OHP main body, 2 denotes a light source disposed in the main body 1, that is, a halogen lamp, and 3 denotes a light beam of light emitted from the halogen lamp 2. Reference numeral 4 denotes an internal mirror disposed in the main body 1, and 5 denotes a pair of Fresnel lenses disposed on the upper surface of the main body 1. A light-transmissive original (transparency, also referred to as TP) 6 is placed thereon upon projection. . Reference numeral 7 denotes a projection lens, and reference numeral 8 denotes a projection mirror that guides light passing through the projection lens 7 toward a screen (not shown).

The bracket 9 holding the internal mirror 4 is rotatable about a fulcrum 9a, and a part of the internal mirror 4 projects from the bottom surface of the main body 1 during projection. In this case, the main body 1
Are kept at a predetermined distance from the desk surface by the legs 10 that can be stored. A micro switch 11 is provided inside the main body 1 in an electric path between a power supply and a halogen lamp. At the time of projection, the actuator of the micro switch is pushed up by a bracket 9, and the switch is turned on. State. Conversely, when not in use, the internal mirror 4 is
When stored inside, the micro switch 11 turns off,
The halogen lamp 2 is disconnected from the power supply.

Reference numeral 13 denotes a bracket having one end rotatably connected to the main body 1 and the other end rotatably holding the projection lens 7 and the projection mirror 8, respectively. Reference numeral 12 denotes a lock lever that locks at a predetermined position and angle when the bracket 13 is set up. The projection lens 7 is rotatable with respect to the bracket 13 with the pin 17 as a fulcrum, but as shown in FIG. 5 (a), a pressure bracket 19 fixed integrally with the projection lens 7 is provided. The lens 7 is pressed by a spring 20 against a positioning pin 21 fixed to the bracket 13, and the lens 7 is positioned so as to be parallel to the Fresnel lens 5 during projection. The projection mirror 8 is also fixed at an arbitrary position.

In such a configuration, light emitted from the halogen lamp 2 is reflected by the internal mirror 4 and
And the document 6 placed on the projection lens 7
Focus on The light passing through the projection lens 7 is reflected by the projection mirror 8 and directed to a screen, on which an original image is enlarged and displayed.

Next, when stored in a non-use state, when the lock lever 12 is moved right and left, the lock of the bracket 13 is released, and the bracket 13 rotates to the left around the pin 14. When the bracket 13 is put on the main body 1, the projection lens 7 comes into contact with the edge of the main body 1 as shown in FIG. , And as shown in FIG. 5 (c), it fits in contact with the side surface of the main body 1. On the other hand, the projection mirror 8 has its bracket 16 rotatable around the pin 17, so that after the projection lens 7 is settled on the side surface of the main body 1,
Fits in contact with the lower surface of the main body 1.

At this time, both the leg 10 and the internal mirror 4 are pushed by the projection mirror 8 and housed in the main body. The stored state is as shown in FIG. 2 or FIG.

When the bracket 9 rotates so that the internal mirror 4 is housed in the main body 1, the actuator of the micro switch 11 is released, the micro switch 11 is turned off, and the halogen lamp 2 is disconnected from the power supply. Therefore, even if the main switch is turned on, the halogen lamp 2 does not light.

The function in which the legs 10 are stored by the projection mirror being settled on the lower surface of the main body will be described. FIG. 6 shows an embodiment, and FIG. 7 is an exploded perspective view thereof. Reference numeral 10a denotes one leg, which is always urged by a spring 25 in the opening direction. Reference numeral 10b denotes the other leg, which has a shape obtained by bending a rod, the cross section of the bent end portion of which is an oval shape, and which is inserted into the bracket 26. The bracket 26 is urged by a spring 27 in a direction in which the leg 10b opens. Further, the leg 10b is connected to the bracket 9 of the internal mirror by a wire 28.

Therefore, when the head portion is folded when not in use and the projection mirror 8 is settled on the lower surface of the main body 1, one of the legs 10a is pushed by the bracket 16 to which the projection mirror is attached, and is housed in the main body. When the bracket 9 is pushed and housed in the main body, the wire 28 is pulled and the other leg 10b is also housed. When the projection mirror 8 is removed, the legs 10a and 10b are automatically opened by the biasing springs 25 and 27, respectively.

Note that, as in the other embodiment shown in FIG.
0b with the pulley 29 and the crossing wire 30
When the 10a is stored, the leg 10b may be rotated and stored by the rotation. The legs are always urged to open by a spring (not shown).

FIG. 9 shows still another embodiment of the leg.
10c and the main body 1 are connected by a bracket 31. Three
Reference numerals 2 and 33 denote rotatable shafts. At the time of projection, as shown in FIG. 9A, the leg 10c is pulled out, and the bracket 31 contacts the main body side stopper portion 34 and the leg side stopper portion 35, respectively. The position is fixed by contact. When the projection mirror 8 is folded, as shown in FIG.
When c is pushed, the bracket 31 rotates, and the leg 10c is automatically stored in the main body 1.

FIG. 10 shows an OHP according to a second embodiment of the present invention, which has various improvements. FIG. 11 is an exploded perspective view of FIG.

First, in the first embodiment, when the bracket 13 is set up, the lock lever 12 is used to fix the bracket 13 at a predetermined set position. In the present embodiment, the arm 41 corresponding to the bracket 13 is made of an elastically deformable resin. As a molded product, a projection 44 as shown in FIG. 12 (b) is integrally provided on the inner wall, and a stopper for the stopper is also provided on the corresponding side surface of the main body 1 as shown in FIG. 12 (a). Are provided integrally. Then, when the arm 41, which is rotatably supported at one end by the fulcrum 42, is set up, the arm is elastically deformed and the projection 43 is formed.
And is locked in the set state at that position. Protrusion
43 and 44 are each tapered to make it easier to get over, but the set arm 41 is designed not to fall down by gravity, and when you defeat it by applying a little force by hand when defeating,
The protrusion can be easily overcome. With such a configuration, the lock lever as in the first embodiment becomes unnecessary.

At the other end of the arm 41, a projection lens unit 45 and a stay 46 for holding the projection mirror 8 are rotatably held. In this case, the opposite end surfaces of the projection lens unit 45 are located immediately inside the holding portions 41a provided at both ends in the width direction of the other end of the arm, and the stay 4 is provided outside the holding portion 41a.
The sixth mounting portion 46a is positioned and held coaxially and rotatably by a pivot screw 47. As the arm 41 rises and is set to a predetermined projection position, the projection lens unit 45 is also urged to rotate to a prescribed angle (similar to the first embodiment). The projection mirror 8 is
It is attached to 46 by, for example, bonding, from 0 degrees to 20 degrees.
The arm 41 can be rotated with respect to the arm 41 so that a projection elevation angle of about degrees can be obtained, and can be held at an arbitrary angle by a brake friction force.

Reference numeral 48 denotes a light-shielding plate rotatably provided on the projection lens unit 45, which prevents light that does not pass through the projection lens among the light emitted from the light source 2 from reaching the projection mirror 8 directly. Without this light-shielding plate, part of the incomplete condensed light beam emitted from the light source 2 and scattered by the Fresnel lens 5 directly reaches the projection mirror 8 without passing through the lens, is reflected and illuminates the screen. This causes a decrease in contrast and uneven illuminance. Therefore, the provision of the light shielding plate 48 increases the contrast and improves the quality of the projected image. The light shielding plate 48 is urged by a spring (not shown) so that it always projects horizontally to the side surface of the lens unit 45. When stored, it can be folded as described below.

In the first embodiment, when the projection lens is folded when not in use, the projection lens is exposed on the side surface of the main body, and there is a possibility that a finger may be attached or scratched by touching the lens. Therefore, a lens cover that covers and protects the lens during storage is required. However, a lens cap or the like like an ordinary camera is likely to fall off and be lost, and further is inconvenient. In the present embodiment, with a minimum size, without falling off,
In addition, a lens cover is provided which automatically opens and closes the lens surface when projecting and storing.

Reference numeral 49 denotes this type of lens cover, which is made of a flexible thin plate or sheet made of metal or resin. The lens cover 49 has one end fixed to the arm 41 as shown in FIG. 13 or the housing 50 of the projection lens unit 45 as shown in FIG. It is housed on the back of the photographing mirror 8 in the stay 46 as an end. Therefore, as shown in FIG. 15 (a), when the arm 41 is tilted down and the lens unit 45 is rotated and housed so as to be in contact with the side surface of the main body 1 and the projection mirror 8 is in contact with the lower part of the main body, The lens cover 49 housed in the projection lens 51 is sequentially pulled out and covers the upper part of the lens so that a fingertip or the like does not enter the surface of the projection lens 51. This can cause fingerprints on the lens,
The lens is completely protected from being damaged.

Since the lens cover 49 is made of metal or resin and has a moderate stiffness, the free end of the lens cover 49 is sequentially placed in a storage portion such as a stay when the arm is set up at the projection position with the arm raised. As the camera enters, the projection lens is completely exposed in the set state, and is automatically ready for projection.

Note that one end of the lens cover 49 may be fixed to the stay 46 and the free end may be inserted into and removed from the arm 41. Also, OHP
When folded, the light shielding plate 48 is positioned between the lower surface of the main body 1 and the projection mirror 8 as shown in FIG. 15 (a) or between the side surface of the main body and the lens unit 45 as shown in FIG. 15 (b). It can be stored and has no support for folding.

As a conventional OHP focus adjustment mechanism, one or more grooves are carved in the helicoid screw or lens barrel,
The pin coming out of the outer cylinder is engaged with this, the outer cylinder is fixed to the body, the lens moves up and down by rotating the inner cylinder, or the pin of the lens barrel is inserted into the groove of the outer cylinder In general, this structure requires an inner cylinder and an outer cylinder, which increases the overall outer diameter, and requires a longer outer cylinder to move the lens barrel up and down. However, there has been a problem that it is difficult to increase the cost and the cost increases.

In this embodiment, a small-sized and low-cost focus adjusting mechanism having a simple structure is provided. FIG. 16 shows an embodiment of the focus adjustment mechanism, in which one side surface of a projection lens 51 is displaceably supported by vertically parallel plate springs 52, 53 having one end fixed to a housing 50. I have. An engagement pin 54 is provided on the side surface of the projection lens 51 opposite to the support, and the tip of the engagement pin 54 is engaged with a cam 56 having an adjustment knob 55. Therefore, when the knob 55 is rotated, the engagement pin 54 moves along the cam groove, whereby the projection lens 51 is displaced up and down, so that the focus can be adjusted. Even if the projection lens 51 is displaced up and down, the pair of upper and lower leaf springs 52 and 53 have exactly the same thickness, length and width, so they are in the same bending state, and as a result, the optical axis of the lens is completely vertical. Move up and down while maintaining At this time, the lens slightly shifts in the longitudinal direction of the leaf spring, but this shift does not pose any problem in practical use.

In this configuration, since a leaf spring is used, a force for always returning the lens itself to the neutral point is generated. Therefore, in order to fix the lens at an arbitrary position, the reaction force of the leaf spring is supported. It is sufficient if there is a cam surface only on the side, and this cam surface and the engaging pin 54 are in close contact with each other without any gap.

FIG. 16 shows a configuration in which the adjustment knob 55 and the leaf springs 52 and 53 are orthogonal to each other, the spiral groove is used for the cam groove, and the leaf spring is used on both sides of the neutral point. The cam development is shown in FIG.

FIG. 18 shows another embodiment of the focus adjustment mechanism in which the focus adjustment knob 55 is arranged in parallel with the leaf springs 52, 53.
The shape of the cam 57 is a slope type, and a leaf spring is used in the same displacement direction. The cam development is shown in FIG.

The amount of movement of the lens for focusing is given by the following equation.

Where: f: focal length of the lens a: distance from the lens to the document b: distance from the lens to the screen Therefore, the shorter the distance from the lens to the document, the greater the distance from the lens to the focused screen surface in inverse proportion Change. In other words, when trying to focus on a fixed screen position, the position where the distance between the lens and the document is short, that is, the position where the lens is low must be adjusted more finely than the position where the lens is high. No.

Therefore, in the cam development diagram that graphs the cam displacement and the rotation angle of this cam, that is, the adjustment knob, the cam is manufactured not in a straight line but in a hyperbolic shape, so that the adjustment knob rotation angle and the in-focus position are completely proportional. The focus adjustment work is greatly facilitated. Practically, almost the same effect can be obtained by making the shape close to a hyperbola, that is, making the inclination on the high magnification side gentler than the inclination on the low magnification side.

Also in the case of this embodiment, since the internal mirror 4 projects to the lower part of the main body at the time of projection, a leg for lifting the main body is necessary,
In particular, a structure in which the legs automatically come out during use is desirable.

FIG. 20 shows such a leg, in which a front leg 58 and a rear leg 59 are arranged on the bottom side of both sides of the main body, respectively, and can be bent at the center. That is, as shown in FIG. 20 (a), the arm 41 is urged by the spring 60 so as to be straight when the arm 41 is tilted, and as shown in FIG.
When setting the camera to the position where projection is possible with the
The rear leg 59 is pushed by the end of 41, and as a result, the rear leg 59 projects downward, and the front leg 58 also projects downward via the cam mechanism 61. Since the arm 41 is fixed by the projection 43 in the set state, the leg is also fixed.

(Effects of the Invention) As described above, as is clear from the description of the embodiments, the present invention
A light transmission type OHP in which an internal mirror is arranged between the light source and the Fresnel lens, and the projection head is held on a bracket or arm that stands up from the main body.When not in use,
The bracket (arm), the projection lens, and the projection mirror are housed so as to be in contact with the top, side, and bottom surfaces of the main body, respectively. At the time of projection, the internal mirror projects partly from the bottom of the main body and the legs open, but the housing is closed. At times, they are housed inside the body and are therefore folded very compactly, so that the space factor is very good and sufficiently thin and compact.

Further, when the internal mirror is housed, the power supply electric path to the light source is cut off, so that safety is improved. In addition, the operability is improved because the legs are automatically moved in and out,
In the stored state, the Fresnel lens is covered by the bracket (arm), and the projection mirror is also stored facing inward, so that they can be protected.

Further, in the second embodiment, when stored, the projection lens is covered by the cover, and the lens is completely protected. In addition, the lens cover automatically opens and closes the lens surface according to the set or storage, so that it is extremely easy to use and does not hinder miniaturization.

The focus adjustment mechanism has a simple structure, is smaller in size than conventional inner and outer cylinder types, and therefore allows the use of a bright lens and achieves a significant cost reduction.

The stopper mechanism when the arm is raised also effectively utilizes the elastic deformation of the resin, and the structure is simplified, for example, by omitting the lock lever.

 It has remarkable effects.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state of the OHP according to the first embodiment of the present invention at the time of projection, FIG. 2 is a diagram showing a state of the OHP when the OHP is stored, and FIGS. 2 is an external view in the state of FIG. 2, FIG. 5 is an explanatory diagram of the operation when the projection lens unit is housed, FIG. 6 is a configuration diagram of one embodiment of the leg unit, and FIG. FIG. 8 is an exploded perspective view, FIG. 8 is a configuration diagram of another embodiment of the leg portion, FIG. 9 is a configuration diagram of still another embodiment of the leg portion, and FIG.
The figure which shows the state at the time of projection of OHP of the 2nd Example of this invention.
11 is an exploded perspective view of FIG. 10, FIG. 12 is a configuration diagram of an arm stopper portion, FIGS. 13 and 14 are cross-sectional views of a housing portion of a lens cover, respectively, and FIG. FIG. 16 is a diagram showing a state in which the lens cover covers the lens at the time of storage, and a storage state of the light shielding plate at that time, FIG. 16 is a configuration diagram of one embodiment of a focus adjustment mechanism, and FIG. Cam development, No.
FIG. 18 is a configuration diagram of another embodiment of the focus adjustment mechanism, FIG. 19 is a cam development diagram of the embodiment, and FIG. 20 is a configuration diagram of the legs. 1 OHP main body 2 Halogen lamp 4 Internal mirror 5 Fresnel lens 7 Projection lens 8 Projection mirror 9,13,16 Bracket 10,10a, 10b , 10c …… legs, 11…
... Micro switch, 12 ... Lock lever, 20,25,27 ... Spring, 41 ...
Arm, 43 Projection for stopper, 45 Projection lens unit, 46 Stay, 48 Light shield plate, 49 Lens cover, 52, 53 Leaf spring, 55 Adjustment knob, 58 Front legs, 59 ... Rear legs.

Claims (11)

(57) [Claims] A light source disposed in an overhead projector main body, a Fresnel lens disposed on an upper surface of the main body, an internal mirror for reflecting light emitted from the light source toward the Fresnel lens, and the main body. A projection lens that is held by a bracket that rises from above and forms an image of light passing through the Fresnel lens and a projection original placed thereon, and a projection mirror that directs light from the projection lens toward a screen. In the overhead projector provided, the internal mirror is provided rotatably, and a part of the internal mirror projects outside from the bottom surface of the main body at the time of projection, and is stored in the main body when not in use. An overhead projector, characterized in that: 2. The overhead projector according to claim 1, further comprising means for operating when the internal mirror is housed in the main body, by operating the housing to cut off an electric path between the light source and the power supply. An overhead projector, characterized in that: 3. A light source disposed in the main body of the overhead projector, a Fresnel lens disposed on an upper surface of the main body, an internal mirror for reflecting light emitted from the light source toward the Fresnel lens, and the main body. A projection lens that is held by a bracket that rises from above and forms an image of light passing through the Fresnel lens and a projection original placed thereon, and a projection mirror that directs light from the projection lens toward a screen. In an overhead projector, one end of a bracket holding the projection lens is rotatably connected to a main body, and the projection lens is rotatably connected to the other end of the bracket. Spring member and stopper means for urging the projection lens to be held parallel to the Fresnel lens Has, when folded the bracket to the body side when not in use, an overhead projector the projection lens, characterized in that it is housed in contact with the body side. 4. The overhead projector according to claim 3, wherein said projection mirror is further rotatably connected to the other end of a bracket for holding said projection lens, and said bracket is used when not in use. When the is folded toward the main body, the bracket covers the upper surface of the main body, the projection lens is housed on the side surface of the main body, and the projection mirror is housed so as to be in contact with the lower part of the main body, respectively. 5. The overhead projector according to claim 4, further comprising legs provided on the main body.
An overhead projector, further comprising means for automatically accommodating the legs in conjunction with an operation of accommodating the projection mirror in a lower portion of the main body. 6. A light source disposed in an overhead projector main body, a Fresnel lens disposed on an upper surface of the main body, an internal mirror for reflecting light emitted from the light source toward the Fresnel lens, and one end thereof. An arm rotatably connected to the main body, a projection lens unit and a projection mirror rotatably held at the other end of the arm, the arm standing when projecting, and the arm when not in use. In the overhead projector, the projector lens unit is turned on the side of the main body and the projection mirror is rotated and stored so as to be in contact with the lower part of the main body, respectively, from a flexible thin plate or sheet made of metal or resin. When the arm is set up, it is stored in a stay holding the projection mirror or in the arm, Serial overhead projector when defeating arms, characterized in that a lens cover that covers the surface of the projection lens unit and the rotation of the projection mirror, drawn in conjunction with the housing projection lens. 7. A light source disposed in the main body of the overhead projector, a Fresnel lens disposed on the upper surface of the main body, an internal mirror for reflecting light emitted from the light source toward the Fresnel lens, and one end thereof. In an overhead projector comprising an arm rotatably connected to the main body, and a projection lens unit and a projection mirror held at the other end of the arm, holding provided at both ends in the width direction of the other end of the arm The projection lens unit is configured to rotatably hold opposing side surfaces of the projection lens unit inside the unit, and rotatably hold a stay holding the projection mirror outside the holding unit. Overhead projector. 8. A projection lens portion of an overhead projector, wherein one side surface of the projection lens is displaceably supported by a pair of upper and lower parallel leaf springs having one end fixed, and a side surface opposite to the support portion of the projection lens. An overhead projector characterized in that an engaging portion provided in (1) is engaged with a cam provided with an adjusting knob, and the focus is adjusted by rotating the knob to displace the projection lens. 9. A light source disposed in the main body of the overhead projector, a Fresnel lens disposed on the upper surface of the main body, an internal mirror for reflecting light emitted from the light source toward the Fresnel lens, and one end thereof. In an overhead projector including an arm rotatably connected to the main body, and a projection lens unit and a projection mirror held at the other end of the arm, light emitted from the light source does not pass through a projection lens. An overhead projector, wherein a light shielding plate for preventing light from directly reaching a projection mirror is provided in a projection lens unit. 10. A light source disposed in an overhead projector main body, a Fresnel lens disposed on an upper surface of the main body, an internal mirror for reflecting light emitted from the light source toward the Fresnel lens, and one end thereof. An arm rotatably connected to the main body, a projection lens unit and a projection mirror rotatably held at the other end of the arm, the arm standing when projecting, and the arm when not in use. In an overhead projector in which the projection lens unit is turned to the main body side and the projection mirror is rotated and stored so as to be in contact with the lower part of the main body, the arm is made of an elastically deformable resin. The over position is characterized in that when projected, the projection provided on the side of the main body is moved over by elastic deformation and positioning during projection is performed. Head projector. 11. A light source disposed in the main body of the overhead projector, a Fresnel lens disposed on the upper surface of the main body, an internal mirror for reflecting light emitted from the light source toward the Fresnel lens, and one end thereof. An arm rotatably connected to the main body, a projection lens unit and a projection mirror rotatably held at the other end of the arm, the arm standing when projecting, and the arm when not in use. In the overhead projector, the projector lens unit is turned on the main body side and the projection lens unit is rotated and housed so as to be in contact with the lower part of the main body, respectively. It is bendable, and is urged by a spring so as to be straight when the arm is tilted, and the end of the arm when the arm is raised An overhead projector, characterized in that both ends one end is pressed is provided a leg projecting downward.