JPH03214139A - Light emitting device for overhead projector - Google Patents

Abstract

PURPOSE:To reduce the cost of this light emitting device by providing a recessed part and a projecting part provided between a case and a slide member which are engaged at a position where one of lamps is alternatively opposed to a condeser lens. CONSTITUTION:A pair of holes for positioning 28 (the recessed parts) is formed to a holding plate 20 at the outside circumferential part of the condenser lens 15 and a pair of holes 28 is provided at the interval of the left and right direction (a top and bottom direction in a figure) of a head 2. Then, when the projecting part 27 of the slide member 21 is inserted in either at the holes 28, the center of on lamp 14 conincides with the optical axis of the condenser lens 15. By positioning the lamp 14 with the aid of using the recessed parts 28 and the projecting part 27 provided between the case 10 and the slide member 21 in such a way, the light emitting device whose structure is simple and which is inexpensive is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light emitting device, particularly to a light emitting device for an overhead projector.

(Prior Art) For example, a reflective type over-double radiator has a base on which a translucent original is placed, and a head disposed above the base.

The head includes a light emitting device having a lamp and a condenser lens, a projection device having a projection lens and a projection mirror,
It also includes a case to store them.

The light emitting device placed inside the case is provided with a pair of lamps including a spare lamp. The lamps are supported on a slide member such that either lamp can be placed in a position of use. A lever is connected to the slide member via a link mechanism. By operating this lever, the slide member can be slid via the linkage mechanism, and the lamp can be alternatively placed in the use position.

[Problems to be Solved by the Invention] In the configuration of the conventional light emitting device, a lever and a link mechanism are essential as a configuration for sliding the lamp. Therefore, the structure of the light emitting device becomes complicated and the manufacturing cost inevitably increases.

An object of the present invention is to provide a light emitting device for an overhead projector that can be manufactured at low cost.

[Means to solve the problem]

A light emitting device for an overhead projector according to the present invention includes a case, a pair of lamps disposed within the case, a condenser lens disposed on the irradiation side of the lamps, and a structure in which the lamps are slidably supported by the case and fixed. and a sliding member. Furthermore, the device includes four parts and a convex part provided between the case and the sliding member, which engage and mate in a position where one of the lamps alternatively faces the condenser lens.

[Function] In the light emitting device for an overhead projector according to the present invention, when changing the lamp to be used, the slide member is slid. Then, the concave portion and the convex portion are engaged with each other at a position where the desired lamp faces the condenser lens. This allows accurate positioning of the lamp after the change.

Here, since the lamp is positioned using the four parts and the convex part provided between the case and the slide member, the structure is simple and the light emitting device can be manufactured at low cost.

〔Example〕

FIG. 1 is a schematic perspective view of an overhead projector employing an embodiment of the present invention. In the figure, the overhead blogger includes a base 1 on which a document is placed, a head 2 placed above the base 1, and a stay 3 that stands up from the base 1 to support the head 2 from below. There is.

The base 1 is a molded product made of resin, and has a space 4 therein for housing the head 2 and the stay 3, as shown in FIG. A flat plate-shaped M5 is placed on the upper end of the base 1. A Fresnel lens 6 is fixed to the top surface of the lid 5. A notch 7 is provided in the sliding member of the lid 5, and the stay 3 is fitted into the notch 7.

The head 2 has a case 10 mainly made of resin. Inside the case 10, there is a base side (stay 3 side)
A light emitting device 12 having an air blower 11 is housed in the space, and a projection device 13 placed ahead of the light emitting device 12 is housed. Further, the blower device 11 includes a fan (not shown) and a motor that rotates the fan. Furthermore, the light emitting device 12
is a lamp 14 arranged in the center, and a lamp 14
The condenser lens 15 and the lamp 1 arranged below the
4, and a reflecting plate 16 disposed above the reflector 4. The projection device 13 includes a projection lens 17 that receives reflected light from the base 1 and a projection mirror 18 arranged above the projection lens 17.

The projection lens 17 has a focus adjustment function.

Further, the projection mirror 18 has its base rotatably supported by the case 10 and can rotate around a support shaft 19 .

The lower part of the case 10 is made of sheet metal, and the head 2 with the resin portion of the case 10 removed is as shown in FIG. As shown in FIG. 3, a pair of lamps 14 are provided including a spare lamp. The base of the lamp 14 is fixed to the slide member 21. The slide member 21 is a rod 2 extending in the left-right direction of the head 2 (vertical direction in FIG. 3).
It is slidably supported by 2. The rod 22 has both ends fixed to the case 10. Inside the slide member 21, a torsion spring 23 is fitted into the rod 22, as shown in FIG. One end of the torsion spring 23 is fixed to the slide member 21 using a screw 24. The other end of the torsion spring 23 is located further forward than the slide member 21 (
The vertical wall 10a of the case 10 is located on the right side of FIG.
It is elastically pressed against. As a result, the lamp 14 is urged downward by the spring force of the torsion spring 23. At the center of the upper end of the slide member 21, a pair of knobs 25 are provided that stand upward from the base side of the slide member 21. This knob 25 protrudes above the projection device 13 side extension portion 16a of the reflection plate 16. A switch 26 is arranged in the case 10 below the slide member 21. This switch 26 switches between the pair of lamps 1 based on the change in the position of the slide member 21.
Lamp 1 placed on condenser lens 15 among 4
The switch is made so that only 4 can be energized. Furthermore, a convex portion 27 that protrudes downward is provided at the lower end of the end portion of the slide member 21 on the lamp 14 side. This convex portion 27 is
As will be described later, this is for positioning the slide member 21 in the extending direction of the rod 22.

A condenser lens 15 placed below the lamp 14 is fixed to a holding plate 20 provided at the bottom of the case 10. A pair of positioning holes 28 (concave portions) are formed in the holding plate 20 at the outer circumference of the condenser lens 15 . As is clear from FIGS. 5 and 6 showing the moving posture of the slide member 21, a pair of holes 28 are provided at intervals in the left-right direction of the head 2 (vertical direction in the figure).

The convex portion 27 (the fourth
If the two lamps shown in the figure are fitted, the center of one of the lamps 14 and the optical axis of the condenser lens 15 will coincide.

As shown in FIG. 4, the reflecting plate 16 has a spherical portion, portions extending downward on both sides of the spherical portion, and an extension portion 16a indicated by -L. This reflective plate 16 is connected to the support member 3
0 to the bottom surface of MB2. The lid 31 is
It is a member made of resin, and has a protrusion 32 provided on the base side of the head 2 and a spring member 33 provided on the tip side. Therefore, the protrusion 32 is locked to the case 10 side,
The lid 31 can be fixed to the upper part of the case 10 by press-fitting the spring member 33 into the hole 34 of the vertical wall 10a.

1131 is fixed to the upper part of the case 10, the knob 25 of the slide member 21 protrudes higher than the extension 16a of the reflection plate 16. On the other hand, at a position corresponding to the knob 25, the extension portion 16a is provided with a notch 35 as shown in FIG. The notch 35 is the head 2
A pair is provided at an interval in the left-right direction (vertical direction in FIG. 7). That is, both notches 35 are provided corresponding to the position where the knob 25 is arranged at the fixed position of the slide member 21 shown in FIGS. 5 and 6.

Below the condenser lens 15, a large diameter hole 10 is formed in the case 10 in a portion corresponding to the condenser lens 15.
b is formed. Further, as shown in FIG. 8, an air intake port 40 is provided on the side wall of the case 10 facing the blower 11 on the base side of the head 2. Further, a large number of ventilation holes 41 are formed in the partition wall between the blower device 11 and the chamber housing the lamp 14 and the like. Furthermore, the lower part of the holding plate 20, the light emitting device 12, and the projection device 1
There are discharge ports 42.4 at the lower part of the partition wall between the
3 is provided.

When using two overhead projectors, a transparent resin original is placed on the Fresnel lens 6 of the base 1 shown in FIG. When the other lamp 14 is turned on, the light from the lamp 14 passes through the condenser lens 15 and is reflected by the Fresnel lens 6, and the reflected light passes through the original and reaches the projection lens 17. Further, the reflected light is reflected by the projection mirror 18, and an image of the original is projected onto a screen (not shown).

When the lamp 14 is turned on, it generates heat, so the blower device 11 is driven. When the fan (not shown) of the blower 11 rotates, outside air is guided into the case 10 from the air intake 140 (FIG. 8), and the cooling air from the blower 11 passes through the ventilation opening 41 and is directed toward the lamp. We arrive at the room where 14th grade is stored. The cooling air cools each part including the lamp 14, and then is discharged downward from the discharge ports 42, 43. The air flow in this case is schematically shown by arrows in FIG. Here, the case 10 including the lid 31 is
No opening for discharging cooling air is provided at the upper end of the case 10, and discharge ports 42 and 43 are provided at the bottom of the case 10.

In other words, since the configuration is such that the cooling air is discharged downward, even if the cooling air is warmed and lightened by the heat generated by the lamp 14, it is easily discharged outside before the cooling air has a sufficient cooling effect. This will prevent things from happening. Therefore, according to this configuration, the inside of the case 10 can be efficiently and widely cooled.

When the use of the overhead projector is finished, the lamp 14 is turned off. Along with this, the supply of cooling air by the air blower 11 is also stopped. Even during the period when the overhead projector is stopped, the upper end of the case 10 including the lid 31 is not provided with an opening for discharging cooling air, so foreign matter will not enter the case from above through the opening. Therefore, even if the head 2 is left for a long period of time without being housed in the space 4 of the base 1, the inside of the case 10 will be less contaminated.

If one of the lamps 14 becomes defective during use of the overhead projector, the overhead projector is first stopped and the lid 31 is lifted upward as shown by the solid line in FIG. 4 to open it. Furthermore, turn knob 25,
The slide member 21 is rotated against the torsion spring 23. As a result, the convex portion 27 is pulled out from the hole 28 of the holding plate 20.

Furthermore, the slide member 21 is slid in the left-right direction of the head 2 using the knob 25, and another lamp 14 is placed at the optical axis position of the condenser lens 15. Then, when the user releases the knob 25, the slide member 21 is rotated by the torsion spring 23, and the convex portion 27 is fitted into another hole 28. Due to the engagement between the convex portion 27 and the hole 28, the lamp 14
positioning is performed accurately. If this positioning is inaccurate, the knob 25 will not match the notch 35 of the reflector 16, and MB2 will not be able to be closed.

This can prevent incorrect setting of the lamp 14. Also, since the position of the slide member 21 changes as the lamp 14 moves, the changeover switch 2
6 is switched. As a result, only the one located at the center of the condenser lens 15 among the pair of lamps 14 can be energized.

In addition, in the use state, the knob 25 is arranged above the extension part 16a of the reflection plate 16 through the notch 35. Therefore, heating of the knob 25 by the lamp 14 is suppressed. Therefore, when a failure occurs in the lamp 14,
Even immediately after the lamp 14 is turned off, the knob 25 can be easily operated with a finger.

[Other Examples]

In the above-mentioned embodiment, positioning was performed by a combination of the convex portion 27 and the hole 28, but by providing a hole in the slide member 21,
The present invention can be implemented in the same manner by providing the holding plate 20 with a convex portion. Furthermore, the present invention can be implemented in the same manner by attaching a bottle as a separate member instead of the convex portion.

Further, the present invention may be employed in a light-emitting device for a transmission type overhead projector.

〔Effect of the invention〕

In the light emitting device for an overhead projector according to the present invention, since the above-mentioned concave portions and convex portions are provided,
The lamp can be positioned with a simple structure without using a complicated link mechanism or the like. Therefore, according to the present invention, a light emitting device can be manufactured at low cost.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an over-seven dovetail projector employing an embodiment of the present invention, Fig. 2 is a schematic vertical cross-sectional view thereof, Fig. 3 is a plan view of the head with the case removed, and Fig. 4 is An enlarged partial view of FIG. 2, FIGS. 5 and 6 are views corresponding to the enlarged partial view of FIG. 3 showing different operating states, and FIG.
The figure is a partial cross-sectional view taken along the line Vl-■ in FIG. 4, and FIG. 8 is a partial vertical cross-sectional view showing the air blowing state. 2... Head, 10... Case, 14... Lamp, 15... Condenser lens, 21... Slide member, 27... Convex portion, 28... Hole, 12... Light emitting Device.

Claims (1)

[Claims] (1) A case, a pair of lamps arranged in the case, a condenser lens arranged on the irradiation side of the lamps, and a slide member slidably supported by the case and to which the lamps are fixed. A light emitting device for an overhead projector, comprising: a concave portion and a convex portion provided between the case and the slide member, the concave portion and the convex portion being engaged with each other at a position where one of the lamps alternatively faces a condenser lens.