JP2844276B2 - Lighting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device used as an optical system such as a copying machine and an image reader.

[0002]

2. Description of the Related Art FIGS. 4A and 4B are a front sectional view and a plan view showing a conventional lighting device. In the figure, 100 is a linear light source, 101 is a parabolic mirror as a fixed reflection member provided in parallel with the light source 100. Parabolic mirror 1
Numeral 01 has a parabolic cylinder surface 102 and is arranged in the short direction, that is, FIG.
It has light condensing power only in the vertical direction.

Reference numeral 103 denotes a light source 1 from a parabolic mirror 101.
The light shielding mirror is provided at a position separated by 00 and parallel to the light source 100. 104 is the parabolic cylindrical mirror 10
A scanning reflector as a moving reflector provided in parallel with 1.
It is configured so as to be able to move in parallel (arrow a) along the direction of approaching / separating from the parabolic cylinder surface mirror 101, that is, along the platen glass 105.

On the other hand, on both ends of the parabolic cylinder surface mirror 101 and the scanning reflection shade 104, a pair of side reflection shades 105 as a pair of side reflection members are provided.

In the above configuration, the light beam b emitted from the light source 100 is reflected by the parabolic mirror 101 and condensed only in the short direction to become substantially parallel light. A light beam directed rightward in the figure from the light source 100 is
The light is reflected by 3 and directed to the parabolic mirror 101.

The light beam b reflected by the parabolic surface mirror 101 is confined within the effective width d in the longitudinal direction, that is, the vertical direction of FIG.

The scanning reflector 104 reflects the light beam b having the width f while moving from the scanning start position indicated by the dotted line to the scanning end position indicated by the solid line, and illuminates the original 106 placed on the platen glass 107. It is guided in a slit shape to the area e.

[0008]

However, in the above conventional example, since the reflectance of the pair of side reflectors 105 is not 100%, a light amount loss occurs each time the light beam b is reflected by the side reflectors 105, and the number of reflections is reduced. As the number of reflections increases, the amount of light absorbed decreases by the number of reflections. For this reason, the absolute light amount of the light beam b reaching the scanning reflector 105 at the scanning end position is smaller than the absolute light amount of the light beam b reaching the scanning reflector 105 at the scanning start position, and the light amount in the irradiation area e becomes smaller. Illumination defects such as reduction occurred.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide an illumination device capable of maintaining a constant amount of light reaching the movable reflecting portion regardless of the position of the movable reflecting member. .

[0010]

In order to achieve the above object, the present invention provides a linear light source, a fixed reflecting member parallel to the light source and having a light condensing power only in the short direction, A moving reflecting member provided in parallel with the fixed reflecting member and capable of parallel movement in a direction approaching / separating from the fixed reflecting member to guide a light beam reflected by the reflecting member to an illumination area; In a lighting device having a fixed reflecting member and a pair of side surface reflecting members arranged in parallel between both ends in the longitudinal direction of the moving reflecting member, the reflecting surface of the fixed reflecting member is an elliptical cylindrical surface, and The dimension in the lateral direction was set smaller than the dimension in the lateral direction of the fixed reflecting member.

A linear light source, a fixed reflecting member parallel to the light source and having a light condensing power only in a short direction, and a light beam reflected by the fixed reflecting member are guided to an illumination area. A movable reflecting member parallel to the fixed reflecting member and freely movable in a direction of approaching / separating from the fixed reflecting member, and between both ends of the fixed reflecting member and the moving reflecting member in the longitudinal direction. In a lighting device having a pair of side surface reflecting members arranged in parallel, the light source is provided at a position displaced from a focal line of the fixed reflecting member toward the movable reflecting member.

[0012]

According to the present invention based on the above configuration, the light beam emitted from the light source is reflected by the fixed reflecting means and is focused only in the short direction. Then, the width of the reflected light beam in the short direction gradually decreases toward the movable reflecting member. for that reason,
When the movable reflecting member is at the movement start position, a predetermined amount of light flux passes by the lateral end of the movable reflecting member, and the absolute amount of light reaching the movable reflecting member is small.

The absolute light amount gradually increases as the movable reflection member moves away from the fixed reflection member, and reaches a maximum at the movement end position.

Therefore, the decrease in the light amount due to the decrease in the reflectance of the side reflection member is offset by the increase in the absolute light amount, and the absolute light amount of the light beam reaching the movable reflection member is always constant.

[0015]

Next, the present invention will be described with reference to the illustrated embodiments. 1A and 1B are a front sectional view and a plan view showing an embodiment of the present invention. Reference numeral 6 denotes a platen glass, which is horizontally mounted on an upper part of a copying machine main body, an image reader and the like (not shown). The original 7 is placed on the upper surface of the platen glass 6.
Is placed.

The light source 1 in which a plurality of light emitting points 50 are arranged in a line is provided inside the copying machine main body, image reader, or the like, that is, below the document table glass 6. The light source 1 is parallel to the platen glass 6 along the longitudinal direction (the vertical direction in FIG. 1B).

Below the platen glass 6, an elliptical cylindrical reflection shade 2 as a fixed reflection member is fixed. The elliptic cylindrical surface reflection shade 2 is parallel to the light source 1, and the reflection surface facing the light source 1 forms an elliptical cylindrical surface 2a. And
The elliptic cylindrical surface reflection shade 2 has no light condensing power in the longitudinal direction, but has light condensing power only in the short direction (the vertical direction in FIG. 1A).

The light source 1 is located on the first focal line of the elliptical cylindrical surface 2a of the elliptical cylindrical reflecting shade 2.

On the other hand, a scanning reflection shade 4 as a movable reflection member is provided below the platen glass 6 with the light source 1 separated from the elliptical cylindrical reflection shade 2. The scanning reflector 4 is movable along the direction of approaching / separating from the elliptical cylindrical reflector 2 and in parallel with the platen glass 6. Also, the short dimension of the scanning reflector 4, i.e., the width h _b, the shorter dimension of the elliptical cylindrical surface reflector 2, i.e., is set smaller than the width h _a.

Further, a light shielding member 5 is fixed between the light source 1 and the scanning reflection shade 4. A reflection surface may be formed on the light-shielding member 5 on the light source 1 side.

A pair of side surface reflection shades 3 as side reflection members are provided below the platen glass 6 and beside the two ends of the elliptic cylindrical surface reflection shade 2 and the scanning reflection shade 4 in the longitudinal direction. It is arranged. The side reflection shade 3 has a rectangular shape,
The upper side reaches the vicinity of the document table glass 6.

[0022] Incidentally, in the figures of this embodiment, the are taken to widen the width of the side reflector 3 than the width h _b of the scanning reflector 4 to just below the platen glass 6, the document from the scanning reflector 4 This is to prevent the light flux from escaping from the width H in the longitudinal direction even while the light flux advances to 7, so that the illumination efficiency in the longitudinal direction and the light amount of a single part do not decrease.

Next, the operation of the above embodiment will be described. The luminous flux E emitted from the light source 1 toward the elliptical cylindrical reflection shade 2 is
The light is reflected by the elliptical cylindrical surface 2a and focused only in the short direction. The width of the reflected light beam E gradually becomes narrower as it proceeds. Further, since the light beam E is reflected by the side reflection shade 3, the light beam E is confined in a substantially box-shaped region having _a width ha and _a width H. When the elliptical cylindrical reflector 2 is at the movement start position A indicated by the dotted line, a predetermined amount of light flux E passes by the short side end of the elliptical cylindrical reflector 2, that is, up and down. The absolute amount of the light flux E reaching the surface reflection shade 4 is small.

The absolute amount of light gradually increases as the scanning reflector 4 moves away from the elliptical cylindrical reflector, and reaches a maximum at the movement end position B.

On the other hand, when the number of reflections by the side reflection shade 3 increases, the light quantity decreases due to the light quantity loss corresponding to the number of times, but is offset by the increase in the absolute light quantity, and the light flux E reaching the scanning reflection shade 4. Is always constant.

Accordingly, the amount of illumination light reaching the illumination area F of the original 7 is constant.

When the scanning reflector 4 moves from A to B, at the point A, the light flux E that has passed through the upper and lower portions of the scanning reflector 4 and has not reached the illumination area F is gradually changed.
Since become hits, quantity of 2 focal line spacing will be lost in the reflectance loss of the side reflector 3, h _a, the scanning reflector 4 so that h _b cancel by selecting optimally under the conditions Can be supplied to There is flexibility in the choice of this solution, in general, more efficient when the light beam is selected to converge at a scanning end position B to a width of about h _b.

FIG. 2 is a diagram showing the concept. (A)
Shows the amount of light lost by the side reflection shade 3 and the like. S is the ratio of the amount of light lost from the moving positions A to B at the side reflection shade 3 and the like. (B) shows a change in the luminous flux captured by the scanning reflector 4 when there is no loss. Here S 'are those determined by the width h _b of the condenser of the elliptic cylinder reflector 2 and the width h _a scanning reflector 4. As will be S = S ', light harvesting and width h _a, by determining the h _b, when the can (about S~0.1 be kept constant almost amount between the movement position A B FIG. 3A shows a second embodiment. In the drawing, reference numeral 60 denotes a parabolic cylinder surface reflector as a fixed reflector, and has a parabolic tube surface 61. The light source 1 is provided in a direction away from the focal line of the parabolic cylinder surface 61, that is, at a position displaced toward the scanning reflector 4 side. The rest is configured similarly to the first embodiment.

With the above configuration, the light beam E reflected by the parabolic cylinder surface 61 becomes narrower as it goes to the right in the drawing, and the same effect as in the first embodiment can be obtained.

FIG. 3B shows a third embodiment. In the third embodiment, the reflecting surface 2a of the elliptical cylindrical surface reflection shade 2 is an off-axis elliptical cylindrical surface. The rest is configured similarly to the first embodiment.

With this configuration, in addition to the effects of the first embodiment, the light flux E reflected by the elliptical cylindrical surface reflection shade 21 is obtained.
Is not shaken by the light shielding member 5, and the light flux E can be used more effectively.

[0032]

As described above, the present invention is configured as described above, so that the light beam can be received uniformly regardless of the moving position of the movable reflector. Therefore, the light amount in the illumination area can be kept constant.

[Brief description of the drawings]

FIGS. 1A and 1B show a first embodiment of the present invention, wherein FIG. 1A is a front sectional view, and FIG.

2A and 2B show an embodiment of the present invention, in which FIG. 2A is a graph showing the amount of light lost by a side reflector, and FIG. 2B is a graph showing a change in a light flux captured by a scanning reflector.

FIG. 3A is a front sectional view showing a second embodiment of the present invention, and FIG. 3B is a front sectional view showing a third embodiment of the present invention.

4A and 4B show a conventional example, in which FIG. 4A is a front sectional view, and FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Elliptical cylindrical reflection shade 3 Side reflection reflection shade 4 Scanning reflection shade 2a Elliptic cylindrical face E Light flux F Illumination area

Claims (2)

(57) [Claims] 1. A linear light source, parallel to the light source,
In order to guide the luminous flux reflected by the fixed reflecting member and the fixed reflecting member having the light condensing power only in the short direction to the illumination area,
A movable reflecting member parallel to the fixed reflecting member and freely movable in a direction of approaching / separating from the fixed reflecting member, and between both ends of the fixed reflecting member and the moving reflecting member in the longitudinal direction. A pair of side reflection members arranged in parallel,
Wherein the reflecting surface of the fixed reflecting member is an elliptical cylindrical surface, and the dimension of the movable reflecting member in the short direction is set smaller than the dimension of the fixed reflecting member in the short direction. Lighting equipment. 2. A linear light source, said light source being parallel to said light source,
In order to guide the luminous flux reflected by the fixed reflecting member and the fixed reflecting member having the light condensing power only in the short direction to the illumination area,
A movable reflecting member parallel to the fixed reflecting member and freely movable in a direction of approaching / separating from the fixed reflecting member, and between both ends of the fixed reflecting member and the moving reflecting member in the longitudinal direction. A pair of side reflection members arranged in parallel,
The lighting device according to claim 1, wherein the light source is provided at a position displaced from a focal line of the fixed reflecting member toward the movable reflecting member.