JPH0787270A - Light source unit - Google Patents

Abstract

PURPOSE:To remarkably reduce cost, and also, to avoid the deterioration of optical accuracy by replacing an expensive 45 degree prism with a planar filter. CONSTITUTION:On a light source base 101, a stem 102 is fixed, and planar glass 204 and a plate reflecting mirror 205 for constituting a planar filter are mounted thereon. The plane glass 204 is stuck and fixed to the vertical surface 101a, and the plate reflecting mirror 205 is stuck and fixed to the 45 degree surface 101b, and has a through-hole 101c for heat radiation. Also, both faces of the plate reflecting mirror 205 are constituted of a full reflecting film and a blue reflecting film, and moreover, on the plate reflecting mirror 205 side of the planar glass 204, an infrared ray cut film is formed. That is, by replacing the 45 degree prism used conventionally with the planar filter, the cost can be reduced, and also, by the infrared ray cut film of the planar filter, infrared rays are emitted in the air, no optical parts is subjected to thermal deformation and the deterioration of optical accuracy is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device most suitable for a light source of an image input device for reading image information of a transmissive or reflective original.

[0002]

2. Description of the Related Art FIGS. 3 and 4 show the overall structure of a film scanner as an example of a conventional image input device. Also,
FIG. 5 shows the configuration of the illumination unit and the projection unit of the film scanner.

The structure of an image input device for reading a document is roughly divided into an illumination unit 1, a scanning unit 2 and a projection unit 3.

The illumination unit 1 functions as a light source and an illumination unit that guides illumination light from the light source onto the document 5. On the plate-shaped base member 14, a light source unit 11 that emits light in a radial direction and mirrors 13 and 12 that change the direction of the light so as to be linear on the surface of the document 5 are attached. Light source 1
1, the mirror 13 and the mirror 12 are covered with a lid member 15, and the lid member 15 has a slit 15 through which illumination light passes.
a is formed. The lid member 15 is fixed to the base member 14 by a claw-shaped hook portion 15b.

The light emitted from the light source unit 11 is reflected by the mirror 1.
The light is converged into a linear shape on the surface of the original 5 by 3 and is bent by the mirror 12 toward the original 5. Therefore, the light from the mirror 12 is reflected by the slit 15 a of the lid member 15.
In the vicinity of passing through, the light has an elongated rectangular shape in cross section. The slit 15a provided in the lid member 15 has a rectangular shape that is slightly larger than the cross-sectional shape of the light, as long as the slit 15a has a size necessary for the illumination light to pass therethrough. A part of the slit 15a is bent inward, and external light from the opening 4 passes through the slit 15a and the light source unit 11
Preventing you from reaching.

The scanning section 2 functions as a holding means for holding and moving the original 5, and an upper carriage 21 and a lower carriage 22 for holding the original 5 in between, and two guide bars 23 arranged in parallel. It consists of and. The upper carriage 21 and the lower carriage 22 are guided by the guide bar 23 while holding the document 5 and can move in the left-right direction in FIG. A rack portion (not shown) is provided in a part of the upper carriage 21, and the scanning portion 2 is moved in the left-right direction in FIG. 3 by this and a pinion (not shown) driven by a stepping motor or the like.

The projection unit 3 uses a CCD to transmit the light transmitted from the document.
It functions as a reading unit that forms an image on the (line sensor) 33, and includes the mirror 31, the lens unit 32, and the CCD 33.
And a projection cover member 16 which covers the whole and is provided with a slit 15a through which the transmitted light of the original 5 passes. Further, a part of the slit 16a of the projection unit cover member 16 is also bent inward similarly to the slit 15a of the cover member 15 of the illumination unit, and external light from the opening 4 is slit 1.
The inside of the projection unit 3 is prevented from passing through 6a. The lid member 15 of the illumination unit 1 and the lid member 16 of the projection unit 3
Has a black surface and is matt-treated so that it does not reflect external light.

Light from the illuminating unit 1 is condensed in a linear shape on the original 5, and after passing through the original 5, the CCD 33
An image is formed on the upper side, and this is read as one line data. At this time, with the original 5 held at the same position, the illumination light is sequentially switched to R (red), G (green), and B (blue), and the reading is repeated. As a result, 1 line of R
GB data is obtained, and the original 5 can be read in color. After the reading of one line (three colors) is completed, the scanning unit 2 moves the document 5 to the next line and reads it again. By repeating such reading and movement a plurality of times, reading for one screen is performed.

As described above, in order to read the color information for one screen by one scanning, the light source unit 11 uses R
Electrically control fast switching of (red), G (green), and B (blue) light. The conventional light source unit 11 has a configuration as shown in FIGS. 6 and 7.

As shown in FIG. 7, a stem 102 is brazed and fixed on a light source base 101. Further, on the light source base 101, the 45-degree prism 104 and the reflection mirror 105 are attached in a state of being attached. The blue mirror film 105a and the total reflection film 1 are provided on both surfaces of the reflection mirror 105.
And 05b (see FIG. 6 (b)). Also,
An infrared cut film 104a is formed on the vertical surface of the 45-degree prism 104 to cut infrared light that deteriorates image quality.

As shown in FIG. 6, on the stem 102,
A plurality of LED chips 110a and 110b are arranged in two rows and bonded. LED chip 110
Around each chip of a and 110b, there is formed a conical reflector portion 102a that reflects light emitted in the lateral direction and emits it upward (in a direction perpendicular to the paper surface of FIG. 6).

The light source unit 11 comprises two rows of LED chips 110a and 110b for emitting light of three colors.
In the LED chip 110a, six blue LEDs each having a small amount of light per chip are arranged in one row.
At 0b, a red LED and a green LED are arranged in the order of GRGGGRG. The light from the LED chips 110a and 110b is emitted directly or after being reflected by the reflector section 102a and above the chips (direction perpendicular to the paper surface of FIG. 6). After that, the blue reflection film 105a or the total reflection mirror 10
The light is reflected by 5b and emitted forward (to the right in FIG. 6), and is condensed by the mirror 13 (see FIGS. 3 and 5) so as to be linear on the surface of the document 5.

Light from the blue LED is reflected by the blue reflecting film 105a, and light from the red LED and the green LED is reflected by the total reflection mirror 105b, so that three colors are obtained when viewed from the right direction in FIG. It is as if they are emitting light from the same position. The originals 5 can be read at high speed by electrically controlling the switching of RGB colors.

[0014]

The 45-degree prism 104 used in the above-mentioned conventional light source device is an expensive optical component, and therefore there is a problem in that the cost of the light source device is increased. Further, in order to cut infrared light that deteriorates image quality, the vertical surface of the 45-degree prism 104 is
Although the infrared cut film 104a is formed, the infrared light reflected by the infrared cut film 104a is reflected by the 45-degree prism 10.
Returning to 4, there is a problem that the 45-degree prism 104 is thermally deformed to deteriorate the optical accuracy.

The present invention has been made in view of the above problems, and an object thereof is to prevent the deterioration of the optical accuracy due to the thermal deformation of the 45-degree prism while reducing the cost.

[0016]

In order to achieve the above object, the present invention provides a light source which emits illumination light, a reflection mirror which reflects the illumination light emitted by the light source, and illumination light which is emitted from the reflection mirror. It is provided with a plane filter that transmits light and a light source holder that holds the light source, the reflection mirror, and the plane filter, and the light source holder is configured to have a reflection mirror support portion that supports the reflection mirror at a predetermined angle.

[0017]

In the light source device having the above structure, the expensive 45 degree prism is replaced with the flat filter, so that the cost can be remarkably reduced. Further, when an infrared cut film is formed on the reflection mirror side of the flat filter, the infrared light reflected by the infrared cut film will be emitted into the air between the reflection mirror and the flat filter. Since there is no optical component that is thermally deformed, it is possible to prevent deterioration of optical accuracy due to thermal deformation.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of a light source device according to the present invention. FIG. 2 is a sectional view showing an embodiment of the light source device according to the present invention.

In FIG. 1, a stem 102 is brazed and fixed on a light source base 101. Light source base 101
Above the flat glass 204 and the flat reflecting mirror 205.
Is placed. The flat glass 204 is the vertical surface 101.
It is mounted on the light source base 101 in a state of being adhered and fixed to a, and the plate reflection mirror 205 is mounted on the light source base 101 in a state of being adhered and fixed to the 45 ° surface 101b. The through hole 101c is a through hole for heat dissipation as described later. The 45-degree surface 101b, the vertical surface 101a, and the through-hole 101c of the light source base 101 do not need to be machined particularly when the light source base 101 is manufactured by die casting.

As shown in FIG. 2, both surfaces of the flat reflecting mirror 205 are composed of a total reflection film 205b and a blue reflection film 205a. An infrared cut film 204a is formed on the flat glass 204 on the side of the flat reflection mirror 205.

In FIG. 2, LED chips 110a and 110b are bonded on the stem 102. A blue LED chip is bonded to the row of the LED chips 110a, and the light ray from this LED chip 110a has an optical path of 45 at the blue reflection film 205a of the reflection mirror 205.
Is converted once. Further, a red LED and a green LED chip are bonded to the row of the LED chips 110b, and the light rays from the LED chips 110b pass through the blue reflection film 205a of the reflection mirror 205, and the total reflection film 205b converts the optical path by 45 degrees. And is aligned with the optical path of the blue ray.

Since the infrared cut film 204a is formed on the reflection mirror 205 side of the flat glass 204, the infrared cut film 2 is formed.
Since the infrared light reflected by 04a is emitted into the air between the reflection mirror 205 and the flat glass 204, there is no optical component that is thermally deformed, and deterioration of optical accuracy due to thermal deformation is prevented. Is possible. The heat released into the air between the reflection mirror 205 and the flat glass 204 is ventilated with the outside air through the through hole 101c.

If the opposite side of the reflection mirror 205 (see FIG. 2)
When the infrared cut film 204a is formed on the flat glass 204 (on the right side of FIG. 4), infrared light is emitted to the flat glass 204 and the flat glass 204 is thermally deformed. Thus, the reflection mirror 20 of the flat glass 204
The reason why the infrared cut film 204a can be formed on the fifth side is that the number of coatable surfaces is increased as a result of replacing the 45-degree prism with a flat glass.

The LED chips 110a and 110
It is also possible to apply light-shielding coating from the upper left direction to the lower right direction in FIG. 1 so that the light emitted from b does not scatter and adversely affect other optical systems.

As described above, by bonding the two flat glasses to the inclined surface and the vertical surface of the light source base, the same effect as in the case of the 45-degree prism is obtained, and the structure is inexpensive. It becomes possible to do. In the above-described embodiments, the case where the flat filter is made of the flat glass 204 has been described, but the flat filter may be made of not only glass but also a resin filter.

[0027]

As described above, according to the present invention, the expensive 4
Since the 5 degree prism is replaced with a plane filter, it is possible to significantly reduce the cost. Further, when an infrared cut film is formed on the reflection mirror side of the flat filter, the infrared light reflected by the infrared cut film will be emitted into the air between the reflection mirror and the flat filter. Since there is no optical component that is thermally deformed, it is possible to prevent deterioration of optical accuracy due to thermal deformation.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a light source device according to the present invention.

FIG. 2 is a sectional view showing an embodiment of a light source device according to the present invention.

FIG. 3 is a partial cross-sectional front view showing an example of a conventional light source device.

FIG. 4 is a partial cross-sectional side view showing an example of a conventional light source device.

FIG. 5 is a perspective view showing an example of a conventional light source device.

FIG. 6 is a top view, a side view, and a top view showing an example of a conventional light source device.

FIG. 7 is a perspective view showing an example of a conventional light source device.

[Explanation of symbols]

 1 Illumination Part 2 Scanning Part 3 Projection Part 5 Original Document 11 Light Source Part 32 Lens Part 33 CCD 101 Light Source Base 101a Vertical Surface 101b 45 Degree Surface 101c Through Hole 102 Stem 102a Reflector Part 110a LED Chip 110b LED Chip 204 Flat Glass 204a Infrared Cut Film 205 Reflective mirror 205a Blue reflective film 205b Total reflective film

Claims (5)

[Claims] 1. A light source that emits illumination light, a reflection mirror that reflects the illumination light emitted by the light source, a flat filter that transmits the illumination light emitted from the reflection mirror, the light source, the reflection mirror, and A light source holding base for holding the flat filter, the light source holding base having a reflection mirror supporting portion for supporting the reflection mirror at a predetermined angle. 2. The light source device according to claim 1, wherein an infrared cut film is formed on the reflection mirror side of the plane filter. 3. The light source device according to claim 1, wherein a through hole is formed in the reflection mirror support portion. 4. The light source device according to claim 1, wherein the reflection mirror support portion and the light source holder are integrally formed. 5. The light source device according to claim 1, wherein the light source is a plurality of types of light sources that emit light of different wavelengths, and the reflection mirror is a dichroic mirror.