JP2001005122A - Illumination device and image sensor, original reading device and information processing system having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an illumination device which makes illumination uniform in the longitudinal direction of a light transmission body without applying a reflection material, etc., to a saw tooth shape part (changing means) by providing a changing means for changing the optical path of a luminous flux toward a surface to be illuminated with a surface, etc., parallel to the surface to be illuminated and a projecting surface. SOLUTION: The constitution having the surface, etc., parallel to the surface to be illuminated and the projecting surface. at the changing means for changing the optical path of the luminous flux toward the surface to be illuminated is adopted. With this device, the direct incident light on the first surface is reflected or diffused by the first surface and is made incident on the second surface. The light is reflected or diffused on the surface of the second surface and is made incident on an exit surface 13 and is emitted to the outside of the light transmission body 10. On the other hand, the direct incident light on the second surface is mostly transmitted through the second surface and is emitted to the outside of the light transmission body 10. The light transmitted through the neighborhood of the vertex of the projecting surface, however, is transmitted again through the projecting surface to be returned into the light transmission body 10 and is made incident on the first surface. The light is subjected to reflection, etc., by the first surface, is partly made incident on the second surface, is further reflected and is emitted from the exit surface 13 so as to illuminate the surface to be illuminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device and an information processing system including the same.

[0002]

2. Description of the Related Art Conventionally, an illumination device provided in an image sensor of a facsimile, an electronic copier, or other original reading apparatus is a discharge tube such as a fluorescent tube, an LED array in which a large number of LED chips are arranged in an array, or a light guide. A bar-shaped lighting device or the like in which an LED chip is arranged at an end of the light emitting device is used.

[0003] In recent years, with the widespread use of facsimile machines and personal computers, scanners have become widespread in ordinary households as peripheral devices thereof. Accordingly, there is a demand for providing a scanner that is smaller and less expensive. Therefore, the lighting device uses the LED chip as the light source,
Moreover, a bar-shaped lighting device using a light guide that requires a small number of LED chips is becoming mainstream.

FIG. 20 is a side view of a conventional bar-shaped lighting device. 20, reference numeral 20 denotes an LED light source that emits a light beam, 10 denotes a light guide made of a light transmitting member having a quadrangular prism, 12 denotes an incident surface of the light beam emitted from the LED light source 20 with respect to the light guide 10, and 11 denotes a light guide. A saw-tooth-shaped portion that emits outside the light guide 10 by reflecting and scattering a light beam propagating through the body 10, an emission surface 13 that reflects the reflected light and the scattered light of the saw-tooth shape portion 11 from the light guide 10, Reference numeral 14 denotes a turning surface that turns back by reflecting a light beam propagated in the light guide 10.

[0005] The light beam emitted from the LED element 20 is a diffused light beam, and is incident on the light guide 10 from the incident surface 12 of the light guide 10. The light flux incident on the light guide 10 is
On the surface other than the sawtooth-shaped portion 11 of FIG. This is because the incident angle on the surface other than the sawtooth-shaped portion 11 satisfies the condition of total reflection.

On the other hand, of the light that enters the sawtooth-shaped part 11 directly or reflected by a surface other than the sawtooth-shaped part 11, the light that satisfies the condition of total reflection (incident angle> total reflection angle) is reflected by the surface. Alternatively, the light is diffused, and a part of the light is emitted from the light emission surface 13 to the outside of the light guide 10 to illuminate the illuminated surface.

[0007] Of the light reflected on the surface other than the saw-tooth-shaped part 11 directly or incident on the saw-tooth-shaped part 11, the light that does not satisfy the condition of total reflection (incident angle <total reflection angle) is the saw-tooth-shaped part. The light passes through the light guide 11 and exits the light guide 10.
By applying a light-reflective paint to the surface of the sawtooth-shaped portion 11, the amount of light transmitted through the sawtooth-shaped portion 11 may be reduced, and the illuminance of the illuminated surface may be improved.

However, if the processing after the formation of the saw-tooth-shaped portion 11 is not performed, an illuminating device can be manufactured at a low cost. Is often done only when it is necessary.

[0009]

However, since the light beam incident on the sawtooth-shaped portion near the LED light source often does not satisfy the condition for total reflection, a light-reflective paint is applied to the surface of the sawtooth-shaped portion. Otherwise, light is transmitted without reflection. As a result, the amount of light irradiated on the illuminated surface on the LED light source side is reduced, and the illuminance is uneven in the longitudinal direction of the light guide.

The incident light amount of the sawtooth-shaped portion is larger near the LED light source. Therefore, when a light-reflective paint is applied to the sawtooth-shaped portion, the amount of irradiation on the surface to be illuminated on the LED light source side increases, and the illuminance becomes uneven in the longitudinal direction of the light guide. For this reason, the conventional lighting device requires a correction circuit to correct the electric signal obtained from the illuminance distribution of the illuminated surface.

For this reason, by applying a reflecting material or the like only to the surface of the sawtooth-shaped portion near the incident surface of the sawtooth-shaped portion, the illuminated surface is irradiated with an increased relative illuminance of the illuminated surface. The light amount is made uniform.

However, when a reflecting material or the like is applied, the manufacturing cost is increased as described above, and the manufacturing process is increased by applying the reflecting material or the like.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an illuminating device that makes the illuminance uniform in the longitudinal direction of the light guide without applying a reflective material or the like to the sawtooth-shaped portion (change means).

It is another object of the present invention to provide an inexpensive lighting device with a small number of manufacturing steps.

[0015]

In order to solve the above-mentioned problems, the present invention provides at least one illuminating means for illuminating a surface to be illuminated with light, and an optical path of a light beam emitted from the illuminating means. A light guide having changing means for changing the direction of the illuminated surface, wherein the changing means comprises a surface parallel to the illuminated surface or a surface having a small angle with respect to the illuminated surface and a convex surface. And at least a part of the light flux incident and reflected on a surface parallel to the illuminated surface or a surface at a small angle with the illuminated surface is incident on the convex surface, is further reflected, and moves in the direction of the illuminated surface. Each is set so as to be emitted.

Further, the present invention provides at least one illuminating means for illuminating a surface to be illuminated with light, and changing means for changing an optical path of a light beam emitted from the illuminating means toward the direction of the illuminated surface. In the illumination device provided, the changing unit includes a region having a convex surface, and includes a convex portion that increases a reflectance or a diffusivity of the light flux.

Further, an image sensor according to the present invention includes any one of the above illuminating devices, and means for condensing light emitted from the illuminating device and reflected or transmitted by a surface to be irradiated.
Converting means for converting the collected light into an electric signal.

Further, the reading apparatus of the present invention includes an image sensor, a driving unit for driving the image sensor, and a unit for regulating the position of the illuminated surface.

Further, the information processing system of the present invention comprises the above-described reading device, means for driving the document reading device, means for converting an electric signal output from the document reading device into an image signal, and Means for displaying the image signal.

That is, according to the present invention, most of the light flux incident on the parallel surface is reflected on the convex surface. The convex portion converts the optical path of the reflected light or the like in the direction of the emission surface.

Further, according to the present invention, the light beam incident on the region having the convex surface is changed to the direction of the exit surface by the convex portion in the same manner as described above.

[0022]

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

(Embodiment 1) FIG. 1A is a side view in the longitudinal direction of a lighting device of the present embodiment. FIG. 1 (b)
It is a side view of the short direction of the lighting installation of this embodiment.

As shown in FIGS. 1 (a) and 1 (b), the illumination device of the present embodiment has an LED on one end face in the longitudinal direction of a light guide 10 having a rectangular cross section made of a light transmitting member. Light source 2
The diffused light emitted from the LED light source 20 is incident on the light guide 10 from the incident surface 12. The incident light changes the optical path inside the light guide 10 and exits from the exit surface 13 to the outside of the light guide. The emitted light is applied to the surface to be illuminated.

In the inside of the light guide 10, for example, a sawtooth-shaped portion 11, which is a sawtooth-shaped optical path changing member, is disposed on a part of the surface facing the emission surface 13.
On the end face where the light source 20 is not provided, a folded surface 14 for reflecting the propagated light is provided. The folded surface 14 is a surface formed by evaporating a metal such as aluminum or applying a metallic gloss paint or a light diffusion reflective paint.

FIG. 2A is a perspective view of the LED light source 2, FIG. 2B is a pattern diagram of the LED light source 20, and FIG. 2C is a circuit diagram of the LED light source 20. In FIG. 2A,
Reference numerals 21, 22, and 23 denote Red-LED, Green-LED, and B, which emit light of three colors of red, green, and blue, respectively.
lue-LED, 24 is a Zener diode, 25 is an electrostatic guard ring, 26 is a lead, 27 is a white resin, 2
Reference numeral 8 denotes a convex portion for positioning the LED.

The LED elements 21, 22, 23 are shown in FIG.
As shown in (b), the lead 2 at the opening of the white resin 27 is formed.
After being adhered on the adhesive 6 and electrically connected by a wire, the surface is protected by a light-transmitting resin.

The Red-LED 21 is, for example, InGa
It is an element made of AlP, and is a Green-LED2
The Blue LED 2 and the Blue-LED 23 are elements made of, for example, GaInN. However, since GaInN is generally a thin film formed on a sapphire substrate, it is easily broken by static electricity generated during handling or the like.

For this reason, as shown in FIG. 2C, the Zener diode 24 is replaced with a Green as an electrostatic protection element.
The n-LED 22 and the Blue-LED 23 are connected in parallel on the circuit. Further, the upper end of the LED light source 20 is provided with an electrostatic guard ring 25, and the electrostatic guard ring 25 is connected to the frame ground (FG) of the main body device to prevent electrostatic breakdown of the LED.

In particular, when the static electricity guard ring 25 is used in a sheet feed type reader, it is possible to prevent static electricity generated during paper passing from being directly applied to the LED.

The LED elements 21, 22, and 23 are connected to the lead 2
6, power is supplied by Red, Green, and Blu.
e is sequentially and independently lit, or two or three colors are lit simultaneously. Also, the LED element is not necessarily Red,
Green and Blue need not be one each, and may not be two or more and the same number. Further, one or more single colors, for example, one green color may be used.

FIG. 3 is a specific perspective view of the light guide 10. In FIG. 3, 15 is a tapered surface, 16 is an LED positioning recess, 17 is a longitudinal positioning pin, and 18 is a warp correcting pin. The other members are denoted by the same reference numerals as in FIG.

Even if the light guide 10 has a complicated shape as shown in FIG. 3, it can be easily mass-produced by emission molding by manufacturing a mold. By forming the shape of the sawtooth-shaped portion 11 in a mold, it can be similarly easily formed by emission molding.

The tapered surface 15 is formed to increase the illuminance on the side remote from the LED light source 20.
By reducing the cross-sectional area of 0, the light flux incident on the sawtooth-shaped portion 11 can be increased. In addition, the LED elements may be arranged not only on one side of the light guide end in the longitudinal direction of the light guide 10 but also on both sides by eliminating the folded surface 14. If at least the light exit surface 13 of the light guide 10 is covered with a light-reflective white cover or the like, efficient illumination can be achieved.

The positioning between the light guide 10 and the LED light source 20 is accurately performed by inserting the positioning projection 28 of the LED light source 20 into the LED positioning recess 16 of the light guide 10. Also, a pin, LE,
It is also possible to form both holes in D20 and insert the pins of the light guide 10 into the holes of the LED 20 to perform both positioning and fixing.

FIG. 4 is an enlarged view of the vicinity of the incident surface 12 in FIG. As shown in FIG. 4, the diffused light beam emitted from the LED light source 20 enters from the incident surface 12 of the light guide 10. At this time, the diffuse light flux is refracted at the interface of the incident surface 12 due to the difference between the refractive index in the air and the refractive index of the light guide 10.

The refraction angle θn of the light beam incident from the incident surface 12 is 1 for the refractive index in the air, n for the refractive index of the light guide 10, θn for the refraction angle, and θh for the total reflection angle (= Asin ( 1 /
n)), it is smaller than the total reflection angle θh, so that θn <θh = Asin (1 / n).

The light guide 10 is generally formed using an acrylic material, and the refractive index n of the acrylic material is generally large.
Is about 1.49. Therefore, the refraction angle θn is about 42 ° at the maximum.

FIG. 5 is an enlarged view of the sawtooth-shaped portion A and the emission surface 13, and a diagram showing a state of a light beam impinging on the vicinity of the LED light source 20. As shown in FIG. 5, the sawtooth-shaped portion A has a first surface substantially parallel to the surface to be illuminated and an angle θr with respect to the first surface.
2 and a convex surface composed of a second surface, and the first surface and the convex surface are alternately arranged.

In FIG. 5, θ1 is the angle between the light beam incident on the first surface and the first surface, θ2 is the angle between the reflected light from the second surface and the first surface, and θ3 is the angle between the first surface and the second surface. The angle θr1 between the reflected light and the normal to the exit surface 12 indicates the angle of the second surface with respect to the first surface. Θ2 = 2θr1−θ
1, θ3 = 90 ° −2θr1 + θ1 holds.

Θ1 of the light beam incident on the sawtooth-shaped portion A is L
In the vicinity of the ED light source 20, there are many things close to θh, so assuming that θ1 = θh, the first condition for setting the angle θr1 of the second surface is that the light guide 20
To emit the reflected light of the second surface to the outside of the
Must be smaller than the total reflection angle θh. Second, the emission light from the emission surface 13 is made as perpendicular to the surface to be illuminated as possible.

Therefore, θr1 is set to 45 ° <θr1 <(90 ° + θh) / 2.

The material of the light guide 10 is acrylic (n =
When 1.49) is used, the angle θr1 of the second surface is preferably set to 45 ° <θr1 <(90 ° + θh) / 2 = 66 °.

Here, the optimum value differs depending on the light distribution characteristics of the LED light source 20 and the structure of the light guide, but in consideration of the fact that the luminous flux θ1 incident on the sawtooth-shaped portion A decreases as the distance from the incident surface increases, Θr1 according to the distance from the incident surface
May be changed.

Further, in FIG. 5, point a is the first surface and the second surface.
A point on the LED light source 20 side that is a contact point with the surface, a point b is a middle point of the convex vertex and the convex bottom surface, and a point c is a contact point between the first surface and the second surface and opposite to the LED light source 20. The point d and the point d indicate the end points of the portion where the incident light of the light guide 10 is directly irradiated on the first surface.

Further, assuming that the height of the convex surface is H, a point-a
The distance P between the points, the distance Q between the points a and c, and the distance R between the points b and d are respectively P = H (1 / tan θr1 + 1 / tan θh) Q = 2H / tan θr1.

Therefore, the distance S from the point c to the point e (the length of the first surface in the longitudinal direction) is S = PQ. In the present embodiment, it is necessary to satisfy S> 0 in order to increase the relative illuminance of the illuminated surface near the incident surface 12.

Next, the optical path of the light incident on the sawtooth-shaped portion 11 will be described. Most of the diffused light beam incident on the light guide 10 from the incident surface 12 repeats total reflection on the inner surface of the light guide 10 except for the sawtooth-shaped portion 11 and propagates inside the light guide 10. The light that has reached the turning surface 14 is reflected by the surface and is turned in the direction of the LED light source 20.

The light incident on the sawtooth-shaped portion 11 during propagation inside the light guide 10 changes its optical path by being reflected or diffused on the surface of the sawtooth-shaped portion 11, and one portion thereof is illuminated. Proceed in the direction of the plane. When the reflected light or the like on the surface of the sawtooth-shaped portion 11 is incident on the emission surface 13, if the reflected light or the like does not satisfy the condition of total reflection, the reflected light or the like is emitted from the emission surface 13 to the outside of the light guide 10, and Irradiate.

That is, when the incident angle θ3 is smaller than the total reflection angle θh, the reflected light or the like is emitted from the emission surface 13 and illuminates the surface to be illuminated, such as a document. on the other hand,
When the incident light θ3 is greater than the total reflection angle θh when the reflected light or the like on the surface of the sawtooth-shaped portion 11 is incident on the light exit surface 13, the reflected light or the like is reflected on the surface of the light exit surface 13 and
From the outside.

Further, as shown in FIG. 5, the incident light on the incident surface 12 may directly enter the saw-toothed portion A. First
Assuming that the light directly incident on the surface is the light directly incident on the first surface, the light is reflected or diffused on the surface of the first surface and is incident on the second surface. Light reflected on the first surface and the like incident on the second surface is reflected or diffused on the surface of the second surface and is incident on the emission surface 13. The reflected light of the second surface and the like incident on the exit surface 13 exits the light guide 10 from the exit surface 13.

On the other hand, assuming that the light directly incident on the second surface is almost the same as the light incident directly on the second surface.
The light passes through the surface and is emitted to the outside of the light guide 10. However, the light transmitted near the apex of the convex surface passes through the convex surface again, returns to the inside of the light guide 10, and enters the first surface.

This light is reflected by the first surface, a part of the light enters the second surface, is further reflected, is emitted from the emission surface 13, and illuminates the surface to be illuminated. Further, one part is incident on a surface other than the second surface, is reflected, and propagates inside the light guide 10.

Further, since the light flux parallel to the surface to be illuminated becomes larger at a position farther from the LED light source 20, the light continuously passes through the convex surface, enters the second surface, is further reflected, and is further reflected. There is also a light beam that illuminates the light.

FIG. 6A is a diagram showing relative illuminance of emitted light of a conventional lighting device with respect to the position of a surface to be illuminated. FIG.
(B) is a figure which shows relative illuminance with respect to the position of the illuminated surface of the emitted light of the illumination device of this embodiment. In the conventional lighting device, θr2 of the sawtooth-shaped portion 11 is set to 35 °.

According to FIG. 6A, the relative illuminance in the vicinity of the incident surface 12 is low, and the relative illuminance increases in the direction of the turning surface 14 and then levels off. In the vicinity of the turning surface 14, the relative illuminance slightly decreases. on the other hand,
According to FIG. 6B, although the relative illuminance slightly decreases near the turning surface 14, the relative illuminance is substantially uniform regardless of the position of the illumination target surface.

(Embodiment 2) In this embodiment, in order to reduce the light that is directly incident on the second surface and emitted to the outside of the light guide 10, the sawtooth-shaped portion 11 described in Embodiment 1 is used.
Is an improvement of

FIG. 7 is an enlarged view of the sawtooth-shaped portion A and the emission surface 13 of this embodiment. In the present embodiment, the angle θr1 of the convex surface of the sawtooth-shaped portion A is the same as that in the first embodiment. Further, the angle of the fourth surface with respect to the first surface is set to, for example, 9
0 °. The length of the first surface is longer than that of the first embodiment by h / tan θr1.

In this embodiment, assuming that the light directly incident on the second surface is, most of the light directly incident on the second surface passes through the second surface and is emitted to the outside of the light guide 10. You. However, the light transmitted near the apex of the convex surface passes through the convex surface again, returns to the inside of the light guide 10, and enters the first surface. This light is reflected on the first surface and propagates inside the light guide 10. In addition, a part of the light enters the second surface, is further reflected, and is emitted from the emission surface 13 to the outside of the light guide 10.

In the convex surface of the sawtooth-shaped portion A shown in FIG. 7, since the angle of the fourth surface with respect to the first surface is set to 90 °, the ratio of the light is larger than the ratio of the light, so that the surface to be illuminated is irradiated. The amount of light can be increased as a whole. As a result, the amount of light emitted from the LED light source 20 can be suppressed, and the lighting device can be driven with low power.

The incident light on the first surface of the sawtooth-shaped portion A exits from the light exit surface 13 to the outside of the light guide 10 through the same optical path as in the first embodiment. The angle between the first surface and the fourth surface is desirably 90 °, but is not limited to 90 °. If the angle between the fourth surface and the first surface is sharper than in the first embodiment, Good.

(Embodiment 3) FIG. 8 is an enlarged view of the sawtooth-shaped portion A and the emission surface 13 of this embodiment. In the present embodiment, the second surface of the sawtooth-shaped portion A is, for example, a paraboloid, and a part of the angle between the first surface and the tangent of the second surface to the first surface is the same as θr1 of the first embodiment. Angle. The length of the first surface is, for example, the same as in the first embodiment.

As shown in FIG. 8, when the second surface is a paraboloid, the light path of the light incident on the second surface is effectively changed to the light exit surface 13. In addition, the shape of the second surface is not limited to the paraboloid, and the same effect as the above and the paraboloid can be obtained as long as the curved surface includes θr1 in one part. In the present embodiment, it is difficult to sharpen the angle between the first surface and the second surface,
This is suitable when a material that becomes dull is used.

(Embodiment 4) FIG. 9 is an enlarged view of the sawtooth-shaped portion A and the emission surface 13 of this embodiment. In the present embodiment, the first surface is inclined by an angle θr3 with respect to the illuminated surface. The angle θ4 between the illuminated surface and the second surface is [θ
r2−θr3]. The condition of θr2 will be described later. The angle θr3 between the first surface and the surface to be illuminated needs to be an angle at which incident light of the sawtooth-shaped portion A does not pass through the first surface at the maximum.

That is, θr3 needs to be an angle that satisfies the condition of total reflection, and is desirably 90 ° -2θh or less. This embodiment is suitable for a case where a material that is difficult to sharpen the angle between the first surface and the second surface is used.

(Embodiment 5) FIG. 10A is a longitudinal sectional view of a lighting device of the present embodiment. In the present embodiment, the saw-tooth-shaped portion 11 is composed of two regions.
The vicinity of the ED light source 20 is constituted by the sawtooth-shaped portion A of the first embodiment, and the other portions are constituted by the sawtooth-shaped portion B shown in FIG. The sawtooth-shaped portion B has the same shape as the conventional sawtooth-shaped portion, and is formed of a sawtooth portion at a gentler angle to the surface to be illuminated than the sawtooth-shaped portion A.

In FIG. 10B, θr2 is the angle of the third surface with respect to the surface to be illuminated, θ4 is the angle between the incident light on the incident surface 12 and the normal to the third surface, and θ3 is the reflection from the third surface. It shows the angle between the light and the normal to the exit surface 13. Also,
θ3 = 0 ° −θr2 and θ4 = 90 ° −θr2 hold.

Since the sawtooth-shaped portion B is formed at a position distant from the LED light source 20, the refraction angle θ at the incident surface 12
A lot near n = 0 ° is incident on the sawtooth-shaped portion B.
Therefore, θr2 is set assuming a light flux of θn = 0 °. The condition is that the angle between the light beam incident on the third surface and the normal to the third surface is larger than the total reflection angle θh,
In addition, the angle θ3 between the light reflected from the third surface and the normal to the emission surface 13 needs to be smaller than the total reflection angle θh.

Therefore, θr2 satisfies (90 ° −θh) / 2 <θr <90 ° −θh.

When acrylic (n = 1.49) is used as the material of the light guide 10, the angle θr2 of the third surface with respect to the first surface is set to 24 ° <θr2 <48 °. It is necessary.

(Embodiment 6) FIG. 11 is a longitudinal sectional view of a lighting device of this embodiment. In the present embodiment, the condition of the convex surface of the sawtooth-shaped portion 11 is the same as that of the sawtooth-shaped portion B of the fifth embodiment. That is, the angle between the illuminated surface and the second surface is set to the same condition.

However, in this embodiment, each of the convex surfaces of the sawtooth-shaped portion C is provided with a finer convex portion. The incident light of the sawtooth-shaped portion C is reflected or diffused by the projection, and changes the optical path in the direction of the emission surface 13. Therefore, the optical path can be changed as in FIG.

In order to provide minute irregularities on the convex surface, it is desirable to provide minute irregularities by sandblasting in a mold for forming a saw-tooth surface in consideration of mass productivity and reduction in the number of manufacturing steps. The serrated surface may be directly roughened by sandblasting. In addition, the diffusivity of light with minute irregularities is
It can be adjusted by changing the type of material to be sprayed at the time of sandblasting, spraying pressure and spraying time.

FIG. 12A is a diagram showing the relative illuminance of the conventional illumination device with respect to the surface to be illuminated. FIG. 12 (b)
It is a figure showing relative illuminance with respect to the position of the illuminated surface of the lighting installation of this embodiment. The conventional lighting device has a sawtooth-shaped surface 11.
A reflective material is applied to the entire surface of the device.

The amount of incident light on the sawtooth-shaped surface 11 is larger in the vicinity of the LED light source. For this reason, as shown in FIG. 12A, when a reflective material is applied to the sawtooth-shaped portion, the amount of irradiation on the illuminated surface on the LED light source 20 side increases, and the relative illuminance in the longitudinal direction of the light guide 10 becomes uneven. Becomes On the other hand, the illumination device of the present embodiment can make the relative illuminance uniform regardless of the position of the surface to be illuminated, as shown in FIG.

(Embodiment 7) FIG. 13 is a side view in the longitudinal direction of a lighting device of this embodiment. In the present embodiment, a minute convex portion is provided on each of the convex surfaces of the sawtooth-shaped portion 11. Note that the sawtooth-shaped portion C has the same conditions as in the sixth embodiment, for example, and the number of the protrusions provided on the convex surface of the sawtooth-shaped portion E is smaller than the number of the protrusions provided on the convex surface of the sawtooth-shaped portion C, for example. , The density of the convex surface is reduced.

In this embodiment, as in the sixth embodiment, the relative illuminance can be made uniform regardless of the position of the surface to be illuminated.

(Eighth Embodiment) FIG. 14 is a sectional view of a flatbed scanner according to the present embodiment, showing the internal configuration. The flatbed scanner according to the present embodiment will be described.

In FIG. 14, reference numeral 200 denotes an image sensor for converting optical information on a surface to be illuminated, such as a document, into an electric signal; 301, a drive motor for scanning the image sensor 200; 302, a drive belt; Glass for regulating the position, reference numeral 304 denotes a glass
A document pressing plate 3 is pressed against 3, and 100 is a document (illuminated surface).

The flatbed scanner shown in FIG.
When a user inputs an instruction by operating an operation unit (not shown), the illumination device provided in the image sensor 200 irradiates the document 100 with light in order to read image information of the document 100.

The driving motor 301 is driven together with the exposure of the illumination device, and the image sensor is moved by driving the driving belt 302 connected to the driving motor 301. The reflected light from the document 100 is transmitted through a lens array of the image sensor 200 as described later.
The light is focused on the photoelectric conversion device 211.

Light incident on the photoelectric conversion device is converted into an electric signal and output to an information processing device (not shown). The information processing apparatus processes the input electric signal and, for example, displays the original 1 on a monitor or the like of a connected personal computer.
00 image information is displayed.

FIG. 15 is a perspective view of the image sensor 200. FIG. 16 is a sectional view of the image sensor 200. The image sensor 200 reads a linear photoelectric conversion element 211, and a sensor array 210 configured by accurately arranging a plurality of linear photoelectric conversion elements 211 on a sensor substrate 212 such as a glass epoxy material in a line corresponding to the length of a document. The lighting device 1 includes a lens array 220 having a lens element and the lighting device 1.

As described above, three colors of red, green, and blue are switched from the illuminating device 1 incorporated in the image sensor 200 while scanning the image sensor 200, and the document 100 is sequentially illuminated. R, G,
The optical information of the three colors B is formed on the photoelectric conversion element 211 by the lens array 220, and the photoelectric conversion element 211 outputs R, G,
The optical information of the B3 color is converted into an electric signal, output to the information processing device, and the entire image of the document is read.

FIG. 16 is a sectional view of the image sensor 200. Reference numeral 230 denotes a frame 230 for positioning and holding the illumination device 1, the sensor substrate 210, and the lens array 220.

The illumination device 1 and the lens array 220 are fixed in a short direction and a long direction by being inserted into a predetermined groove provided in the frame 230 and adhered thereto. Thus, it is possible to correctly irradiate a desired illumination position with light and to form an image in a state where the entire lens array 220 is in focus.

Subsequently, the sensor array 210 is fitted into the frame 230, an adhesive or a part of the frame 230 is fixed, and the leads of the lighting device and the sensor substrate 101 are electrically connected by means such as soldering. Is completed.

FIG. 17 is a cross-sectional view of a sheet feed type image sensor that reads a document while moving the document. This type of image sensor has a cover glass 303 for holding a document adhered to a frame 230. The flatbed scanner of the present embodiment can also use this type of image sensor.

FIG. 18 is a schematic diagram of an image sensor using a reduction lens 230. As shown in FIG. 18, the original illuminated by the illuminating device is not limited to the one using the same magnification lens as described above.
11 can be applied even if it is projected onto a reduced scale.

(Embodiment 9) FIG. 19 is an internal configuration diagram of an information processing system including an image reading device 70 constituted by using the flatbed scanner 72 described in Embodiment 8.

The information processing system of this embodiment is a personal computer (hereinafter, referred to as a personal computer) which is an image reading device 70 and a second control means for inputting and processing image information read by the image reading device 70. And a display 8 for displaying image information processed by the personal computer 80
2 is provided.

The image reading device 70 includes a CPU 71 as first control means for controlling the entire device, a light source and a CCD.
A flatbed scanner 72 configured by a line sensor or the like to convert an image of a document into an image signal, and an analog signal processing circuit 73 that performs analog processing such as gain adjustment on an analog image signal output from the flatbed scanner 72 are provided. ing.

The image reading apparatus uses an A / D converter 74 for converting the output of the analog signal processing circuit 73 into a digital signal and a shading correction process for the output data of the A / D converter 74 using a memory 76. , An image processing circuit 75 for performing image processing such as gamma conversion processing and scaling processing, and an interface 77 for outputting digital image data processed by the image processing circuit 75 to the outside.

The interface 77 is, for example, SC
It is connected to a personal computer 80 according to a standard adopted by a personal computer such as SI or Bi-Centronics. The analog signal processing circuit 73, the A / D converter 74, the image processing circuit 75, and the memory 76 constitute a signal processing unit.

The personal computer 80 includes an external storage device or an auxiliary storage device 81 such as a magneto-optical disk drive or a floppy (registered trademark) disk drive, a mouse / keyboard 83 for inputting commands and the like to the personal computer 80, a personal computer 80 and an image reading device. An interface 84 for transmitting and receiving data, commands, and status information of the image reading device 80 to and from the device 70, a CPU 85 for outputting a reading signal to the image reading device 80, and a control program for controlling the operation of the image reading device 80. And a ROM 86 for storing.

Note that the control program may be executed by the CPU 85 by reading a program stored in a storage medium such as a magneto-optical disk or a floppy disk loaded in the auxiliary storage device 81 into the personal computer 80. .

When the user inputs a reading instruction using the mouse / keyboard 83, the CPU 85 outputs a reading command to the image reading device via the interface 84. The CPU 85 controls the image reading device 70 according to the control program information stored in the ROM 86.

More specifically, the image reading device 70 inputs a reading command through the interfaces 84 and 77. The command is output to the CPU 71. C
When the command is input, the PU 71 outputs a drive signal to the flatbed scanner 72. When the driving signal is input, the flatbed scanner 72 irradiates the document with light from the illumination device and starts reading the document image as described above.

The electric signal read and converted by the flatbed scanner 72 is output to the analog signal processing circuit 73. The analog signal processing circuit 73 performs analog processing such as gain adjustment on the input electric signal, and outputs the electric signal to the A / D converter 74. A / D converter 74
Converts the input analog signal into a digital signal and outputs the digital signal to the digital image processing circuit 75.

The digital image processing circuit 75 performs shading correction or the like on the input digital signal in accordance with the information stored in the memory 76 and outputs the digital signal to the personal computer 80 via the interfaces 77 and 84.
The personal computer 80 outputs the input digital signal to the display 82 directly or via the CPU 85. The display 82 displays image information based on the input digital signal.

[0101]

As described above, in the present invention, the changing means has a surface parallel to the surface to be illuminated and a convex surface.
Therefore, without applying a reflector or the like to the changing means,
It is possible to provide an illuminating device that makes the illuminance uniform in the longitudinal direction of the light guide. In addition, since a reflecting material or the like is not applied to the changing means, an inexpensive lighting device can be provided with a small number of manufacturing steps.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lighting device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a light source (illuminating means) of FIG.

FIG. 3 is an external view of the light guide of FIG.

FIG. 4 is an enlarged view of the incident surface of FIG.

FIG. 5 is an enlarged view of a changing means (sawtooth-shaped portion) in FIG. 3;

FIG. 6 is a comparison diagram of relative illuminance between the conventional lighting device and the lighting device of FIG. 1;

FIG. 7 is an enlarged view of a changing unit of the lighting device according to the second embodiment.

FIG. 8 is an enlarged view of a changing unit of the lighting device according to the third embodiment.

FIG. 9 is an enlarged view of a changing unit of the lighting device according to the fourth embodiment.

FIG. 10 is a longitudinal sectional view of a lighting device according to a fifth embodiment.

FIG. 11 is a longitudinal sectional view of a lighting device according to a sixth embodiment.

12 is a comparison diagram of relative illuminance between the conventional lighting device and the lighting device of FIG. 11;

FIG. 13 is a longitudinal sectional view of a lighting device according to a seventh embodiment.

FIG. 14 is a diagram illustrating a flatbed scanner according to a seventh embodiment.

FIG. 15 is a schematic diagram of the image sensor of FIG. 14;

FIG. 16 is an external view of FIG.

FIG. 17 is an external view of an image sensor.

FIG. 18 is a schematic diagram of a seed feed type image sensor.

FIG. 19 is an internal configuration diagram of the information processing system.

FIG. 20 is a longitudinal sectional view of a conventional lighting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Illumination device 10 Light guide 11 Saw-tooth shape part 12 Incident surface 13 Outgoing surface 14 Folding surface 15 Tapered surface 16 Light source positioning concave part 17 Longitudinal positioning pin 18 Warp correction pin 20 LED light source 21 Red-LED element 22 Green-LED element Reference Signs List 23 Blue-LED element 24 Zener diode 25 Electrostatic guard ring 26 Lead 27 White resin 70 Image reading device 71 CPU 72 Flatbed scanner 73 Analog signal processing circuit 74 A / D converter 75 Image processing circuit 76 Memory 77 Interface 80 Personal computer 81 Auxiliary storage device 82 Display 83 Mouse / Keyboard 84 Interface 85 ROM 86 RAM 100 Document 200 Image sensor 210 Sensor array 211 Photoelectric conversion element Child 212 Sensor substrate 220 Lens array 230 Reduction lens 301 Drive motor 302 Belt 303 Glass

Claims (9)

[Claims] 1. A light guide having at least one illuminating means for illuminating a surface to be illuminated with light, and changing means for changing an optical path of a light beam emitted from the illuminating means toward the surface to be illuminated. In the illumination device, the changing means includes a surface parallel to the illuminated surface or a surface and a convex surface at a small angle with respect to the illuminated surface, and a surface parallel to the illuminated surface or the illuminated surface. And at least a part of the light beam incident on and reflected from the surface at a small angle with respect to the convex surface is set to be incident on the convex surface, further reflected, and emitted toward the surface to be illuminated. . 2. The light guide has an incident surface on which a light beam emitted from the illuminating means is incident, and an exit surface on which the light beam whose optical path has been changed is emitted to the outside. Light at one end in the direction, and at the other end opposite to the one end, having a surface that reflects or diffuses the light beam or a second incident surface that receives a second light beam emitted from a second light source. The lighting device according to claim 1, wherein the lighting device is a transparent member. 3. An angle θr1 formed between at least one surface forming the convex surface and the parallel surface is n, where n is the refractive index of the light guide, and θh is the total reflection angle (= Asin (1 / n)). 2. The lighting device according to claim 1, wherein the following condition is satisfied: 45 ° ≦ θr1 ≦ (90 ° + θh) / 2. 4. Assuming that the length of the parallel surface in the longitudinal direction is R and the height from the parallel surface to the vertex of the convex surface is H, R = H (1 / tan θr1 + 1 / tan θh) -2H /
The lighting device according to claim 1, wherein a condition of tanθr1 ≧ 0 is satisfied. 5. An illuminating apparatus comprising: at least one illuminating means for illuminating a surface to be illuminated with light; and changing means for changing an optical path of a light beam emitted from the illuminating means toward the surface to be illuminated. The lighting device, wherein the changing unit includes a region having a convex surface, and includes a convex portion that increases a reflectance or a diffusivity of the light flux. 6. The illuminating device according to claim 5, further comprising the convex portion having a density that varies depending on a position. 7. An illuminating device according to any one of claims 1 to 6, means for condensing light emitted from the illuminating device and reflected or transmitted by a surface to be irradiated, and an electric signal for condensing the light. An image sensor, comprising: conversion means for converting the image into an image. 8. A document reading apparatus comprising: the image sensor according to claim 7; a driving unit that drives the image sensor; and a unit that regulates a position of a surface to be illuminated. 9. The document reading device according to claim 8, a device for driving the document reading device, a device for converting an electric signal output from the document reading device into an image signal, and the converted image Means for displaying a signal.