JPH04355561A - Picture lighting device - Google Patents

Abstract

PURPOSE:To improve the light utilizing efficiency of a light source by collecting lights radiating from the light source and making the light surely radiate to a picture. CONSTITUTION:A light radiating from a excitation light source 1 radiates to a film 3 and a light radiating from the excitation light source 1 by a reflection body 2 excites a luminescent material in the film 3. The diffusion of the light radiating by the excitation is prevented by a cylindrical lens 4 and the light radiates to a picture on an original 7. Then the reflected light from the picture is sent to a light receiving face of a photoelectric conversion element 6 via a 'selfoc(R)' lens 5 and received and converted therein into an electric signal.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an image input device that photoelectrically converts and inputs an image, for example, a device used for a reading sensor such as a facsimile machine and an image scanner, and is equipped with an illumination light that illuminates the image. The present invention relates to an image illumination device that supplies an image.

0002

2. Description of the Related Art In an image input device (not shown), illumination light irradiated onto an image is reflected by a pixel by a photoelectric conversion element disposed near a document so that its light-receiving surface faces the pixel. Image input devices that detect light and input image information are known, and such image input devices are equipped with an image illumination device for irradiating an image with illumination light.

Conventional image illumination devices use LEDs, fluorescent lamps, etc. as light sources, and these light sources are usually connected to the light source and photoelectric converter so that the light emitted from the light source does not directly irradiate the light receiving surface of the photoelectric conversion element. A light shielding member was provided between the conversion element and the conversion element. In addition, it is placed on the opposite side of the document across the photoelectric conversion element, and the light from the light source illuminates the image through a minute window (slit-shaped opening) formed in this light shielding member. was.

0004

[Problems to be Solved by the Invention] However, in conventional image illumination devices, a light shielding member is provided to prevent the light source from directly entering the photoelectric conversion element, or a light shielding member is provided to prevent the light source from directly entering the photoelectric conversion element. A device that irradiates an image with light has the disadvantage that only about a few percent of the light emitted from the light source is used to illuminate the image, resulting in extremely poor utilization efficiency of the light from the light source. For this reason, in conventional image illumination devices, it is necessary to use a light source that emits more light than the amount of light required for illuminating the image, making it difficult to achieve power savings and miniaturization of the device. The present invention has been made in view of the above circumstances, and is capable of condensing light emitted from a light source and reliably irradiating it onto an image, and improving the efficiency of using light from the light source. The purpose of the present invention is to provide an image illumination device that is easy to use.

[0005]

[Means for Solving the Problems] In order to solve the above problems, an image illumination device according to the present invention provides an image input device that inputs image information by detecting reflected light of illumination light irradiated onto an image using a photoelectric conversion element. An image illumination device that is installed in an image illumination device and that irradiates the image with the illumination light includes an excitation light source that excites the illumination light, and an excitation light source that is formed to partially or entirely envelop the excitation light source, and that emits the illumination light. a film that emits fluorescence or phosphorescence, a photoelectric conversion element that detects the reflected light, and a light shield or reflector that excites the reflected light and is provided between the photoelectric conversion element and the excitation light source. , at least one of the end faces of the film is arranged near a pixel detected by the photoelectric conversion element.

[0006]

[Operation] According to the present invention, the film absorbs the primary light from the excitation light source using the luminescent agent and emits secondary excitation light such as fluorescence or phosphorescence, and also directs the emitted secondary excitation light toward the end surface of the film. It has a characteristic of propagating to the end surface, condenses light from the excitation light source, propagates toward the end surface, and emits the light from the end surface to illuminate an image placed near the end surface. In addition, a light shielding body or a reflector provided between the excitation light source and the photoelectric conversion element prevents the light from the excitation light source from directly irradiating the photoelectric conversion element, and also prevents the light from the excitation light source from being applied to the film. It acts to focus light on the area.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below based on the illustrated embodiments. FIG. 1 shows a schematic configuration diagram of an image illumination device representing an embodiment of the present invention. In FIG. 1, 1 is an excitation light source, 2 is a reflector, 3 is a film, 4 is a cylindrical lens for condensing illumination light, which is a component of the image illumination device, and 5 is a component of the image illumination device. A SELFOC lens, 6 a photoelectric conversion element, and 7 a manuscript. Here, a linear light source such as a tungsten lamp or a xenon lamp is used as the excitation light source 1, and the reflector 2 is made of a metal plate, metal coating film, metal foil, or the like with high light reflectance. While preventing the light emitted from the excitation light source 1 from directly irradiating the photoelectric conversion element 6, the excitation light source 1
The film 3 is provided so that light emitted from the film 3 is efficiently focused on the film 3. The film 3 is formed by dispersing and containing a luminescent agent in a flexible material such as transparent plastic or thin plate glass that is processed into a film shape, and is processed and arranged so as to almost entirely envelop the excitation light source 1. has been done. Note that as the luminescent material, inorganic or organic fluorescent materials used in fluorescent lamps and the like are used.

The characteristics of the film 3 will be briefly explained below. As shown in FIG. 2, when the excitation light source 1 irradiates the surface 3a of the film 3 with light, the irradiation light hν
0 enters the film 3 and is absorbed by the luminescent agent 3c. The luminescent agent 3c that has absorbed the light hv0 from the excitation light source 1 is excited and emits excitation light (fluorescence or phosphorescence) in random directions. A part of the excitation light irradiated from the luminescent agent 3c is transmitted through the surface 3a of the film 3 and emitted to the inside where the reflector 2 is not present, as shown by light hv1 in the figure. However, if the refractive index of the material constituting the film 3 is sufficiently large, most of the excitation light is repeatedly totally reflected at the surface 3a of the film 3 and propagated within the film 3, as shown by light hν2 in the figure. The light is emitted to the outside from the end surface 3b of the film 3. here,
The excitation light that propagates within the film 3 and reaches the end surface 3b is 20 to 30% of the total incident light hν0 due to the luminescent agent 3c.
is absorbed.

Therefore, a film 3 is used, and as shown in FIG. 1, this film 3 is arranged so as to envelop the entire excitation light source 1, and the light emitted from the end face of the film 3 is irradiated toward the image. By doing so, it is possible to efficiently utilize the light from the excitation light source 1 to irradiate the image with illumination light. Next, in FIG. 1, the cylindrical lens 4 attached to the end surface of the film 3 facing the original 7 is provided to suppress the diffusion of light emitted from the end surface 3b of the film 3. Note that instead of the cylindrical lens 4, a cylindrical lens, a parabolic lens, or the like can be used as well.

The photoelectric conversion element 6 shown in FIG. 1 is a well-known CCD.
It is composed of an image sensor, a MOS image sensor, or a light-receiving element array in which a large number of photodiodes, phototransistors, etc. are arranged, and is arranged near the image of the document 7 so that the light-receiving surface faces the pixels. The illumination light emitted from the end surface 3b of 3 and irradiated onto the image via the cylindrical lens 4 is reflected by the pixels, and the optical information obtained from the image is converted into an electrical signal. Furthermore, a 1-magnification optical transmitter such as a SELFOC lens 5 is provided between the photoelectric conversion element 6 and the original 7, and transmits the reflected light from the image to the light receiving surface of the photoelectric conversion element 6 at 1-magnification. It works like this.

Now, in the image input device equipped with the image illumination device having the above configuration, firstly, the light emitted from the excitation light source 1 is irradiated onto the film 3, and the light emitted from the excitation light source 1 is irradiated onto the film 3. With the reflector 2 provided on the surface of the film 3 and the reflector 2 provided on the opposite side of the film 3 from the excitation light source 1, the light emitted from the excitation light source 1 is efficiently reflected in the film 3 without leaking to the outside. Excite the luminescent agent. Second, as described above with reference to FIG. 2, excitation light such as fluorescence or phosphorescence is emitted from the excited luminescent agent 3c, propagated to the end surface 3b of the film 3, and light is emitted from the end surface 3b. . Thirdly, the light emitted from the end surface 3b of the film 3 is prevented from being diffused by the cylindrical lens 4, and is irradiated onto the image of the original 7. Finally, the reflected light from the image is transmitted to the light receiving surface of the photoelectric conversion element 6 via the SELFOC lens 5, where it is received and converted into an electrical signal.

As described above, by using the image illumination device according to the present invention, the efficiency of using light from a light source is significantly improved compared to the conventional method, and the amount of illumination light for an image is increased. The film containing the luminescent agent used in the present invention allows the excitation light source and the sensor to be wrapped in a free shape with transparent plastic or the like, so that the lighting device can be easily miniaturized. Further, as an application example of the present invention, a facsimile machine that can read color originals by incorporating a fluorescent agent or the like that generates light corresponding to red, green, and blue in a film containing a luminescent agent, etc. It can be used for the following devices.

[0013]

[Effects of the Invention] As explained above, according to the present invention,
First, since the efficiency of using light from the light source is high, power consumption can be reduced and the device can be easily miniaturized. In addition, since the efficiency of using light from the light source is high, it is possible to provide an image illumination device that emits a large amount of light, and it is possible to improve the S/N ratio by using it in image input devices such as facsimiles. . Second, by changing the type of luminescent agent contained in the film, it is possible to apply it to a color image input device.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an image illumination device showing an embodiment of the present invention.

FIG. 2 is a diagram of the characteristics of a film used in the image illumination device of the present invention.

[Explanation of symbols]

1 Excitation light source 2 Reflector 3 Film 3a Film (surface) 3b Film (end surface) 3c Luminescent agent 4 Image illumination device (cylindrical lens) 5 Image illumination device (Selfoc lens) 6 Photoelectric conversion element 7 Image illumination device (original)

Claims (1)

[Claims] 1. An image illumination device that is equipped with an image input device that inputs image information by detecting reflected light of illumination light that is irradiated onto an image using a photoelectric conversion element, and that irradiates the image with the illumination light. an excitation light source that excites the illumination light;
A film that is formed to partially or entirely envelop the excitation light source and emits fluorescence or phosphorescence when irradiated with the illumination light, a photoelectric conversion element that detects the reflected light, the photoelectric conversion element and the excitation light source. established between
comprising a light shielding body or a reflector that excites the reflected light,
An image illuminating device characterized in that at least one end surface of the end surfaces of the film is arranged near a pixel detected by the photoelectric conversion element.