Illumination – Plural light sources – Particular wavelength
Reexamination Certificate
2000-07-03
2002-11-05
O'Shea, Sandra (Department: 2875)
Illumination
Plural light sources
Particular wavelength
C362S235000, C362S240000, C362S241000, C257S098000, C174S250000
Reexamination Certificate
active
06474836
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a light source and an original reading device, and in particular, to a light source which is formed by connecting terminals of a plurality of light emitting elements to predetermined positions of a wiring pattern formed in advance on a substrate, and to an original reading device which irradiates light onto an original and reads the transmitted image or the reflected image by light converting elements.
2. Description of the Related Art
In recent years, original reading devices have been realized in which illumination light is irradiated onto an original such as a photographic film, and the reflected or transmitted light, which includes image information of the image recorded on the original, from the original is received by a CCD (charge coupled device) such that the image recorded on the original is read. Processings such as various types of correction are carried out on the image data obtained by the reading. Thereafter, the image is recorded onto a recording material such as a photographic printing paper, or the image is displayed on a display. Such an original reading device is advantageous in that it is easy to make automatic the operations from the reading of an image recorded on an original to the recording of the image onto a recording material such as a photographic printing paper.
In the original reading device described above, conventionally, a white light source such as a halogen lamp or the like has been used as the light source for illuminating the original. However, in recent years, devices have been realized in which, instead of a white light source, an LED light source is used. The LED light source is structured by a plurality of LED elements, which emit colors of RGB (IR (infrared) light can also be emitted in order to detect positions of scratches), being arrayed on a substrate.
By using an LED light source, filters for color separation of the light emitted from the white light source can be eliminated, thus making the structure of the device more simple. Further, setting of the conditions, such as the respective color balances and the like, can be simplified.
Because the amount of output light of an LED light source is generally lower than that of a halogen lamp, the light must be used efficiently. However, light emitted from the respective LED elements of the LED light source is also emitted in directions other than toward the original (some of the light is not emitted toward the original). For example, because the surface of the substrate is generally a color having low reflectance (e.g., a dark green color), light emitted toward the surface of the substrate at which the LED elements are mounted cannot be used as light for illuminating the original, and the efficiency of utilizing the light is poor.
Further, the LED elements are arrayed on the substrate at predetermined pitches. Thus, as opposed to a light source having continuous light emitting points, the distribution of the amount of light illuminated toward the surface of the original is not uniform (known as non-uniformity of the light amount), and thus, a problem arises in that non-uniform density is exhibited in the read image.
Attempts have been made to eliminate this non-uniformity of the light amount by providing a diffusion plate on the optical path. However, the amount of light is reduced due to the diffusion plate, and even more LED elements must be provided in order to obtain the amount of light needed, which leads to an increase in the number of parts.
Further, the LED elements on the substrate of the LED light source break easily due to shocks or the like. Even if only one LED elements breaks, the entire LED light source must be replaced, which results in the problem of high operating costs.
SUMMARY OF THE INVENTION
The present invention was developed in order to overcome the above-described drawbacks, and an object of the present invention is to provide a light source and an original reading device which can emit light uniformly with a low loss of light and with the minimum number of light emitting elements necessary, and in which breaking of light emitting elements on a substrate can be prevented.
In order to achieve the above object, a first aspect of the present invention is a light source structured by a plurality of light-emitting elements being connected to predetermined positions of a wiring pattern formed in advance on a substrate, the light source comprising: a reflecting member provided at a position of the substrate other than positions at which the plurality of light-emitting elements are disposed on the substrate, the reflecting member having a reflectance which is higher than a reflectance of the substrate.
In accordance with the first aspect of the present invention, the reflecting member is provided on the substrate on which the light emitting elements (LEDs, ELs or the like) are disposed such that the reflecting member is not disposed at positions at which the light emitting elements are disposed. (Namely, the reflecting member is disposed at a predetermined position of the substrate, which is other than the positions at which the light emitting elements are disposed.) As a result, the light emitted from the light emitting elements backward (toward the substrate) is reflected forward by the reflecting member. The reflectance of the reflecting member is higher than the reflectance of the substrate. Thus, more light can be reflected forward as compared with a case in which no reflecting member is provided. Together with the direct light emitted directly forward from the light emitting elements, the large amount of reflected light which is reflected by the reflecting member can also be used as effective light source light. The efficiency of light use can thereby be improved.
In a second aspect of the present invention, in the first aspect, the reflecting member is a film which is of a substantially white color and which protects a surface of the substrate.
In a third aspect of the present invention, in the first aspect, the reflecting member is a reflective plate which is provided on the substrate.
The reflecting member may be, as in the second aspect, a substantially white (i.e., a color having a high reflectance) resist film for protecting the surface of the substrate (a corrosion-resistance protective film provided on the surface of the substrate for preventing the wiring on the substrate from being corroded due to oxidation or the like). Or, as in the third aspect, the reflecting member may be a reflecting plate (which is adhered onto the substrate).
A fourth aspect of the present invention is a light source structured by a plurality of light-emitting elements being connected to predetermined positions of a wiring pattern formed in advance on a substrate, wherein a surface of the substrate on which the light-emitting elements are disposed is substantially white.
In a fifth aspect of the present invention, in the fourth aspect, the substrate is a ceramic substrate.
In accordance with the fourth aspect, a substrate is used whose surface, on which light emitting elements (LEDs, ELs or the like) are disposed, is substantially white (i.e., a color having high reflectance). In this way, the light emitted backward (toward the substrate) from the light emitting elements is reflected forward. For example, as in the fifth aspect, a ceramic substrate may be used as the substrate on which the light emitting elements are provided.
In this way, in the same way as in the first aspect, together with the direct light emitted from the light emitting elements directly forward, the large amount of reflected light reflected by the substrate surface on which the light emitting elements are provided can be used as effective light source light. Thus, the efficiency of utilization of light can be improved.
In a sixth aspect of the present invention, the light source of any of the first through third aspects further comprises a tube-shaped light collecting member which is provided at a surface side of the subs
Alavi Ali
Fuji Photo Film Co. , Ltd.
O'Shea Sandra
LandOfFree
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