JPH07154536A - Color picture reader - Google Patents

Abstract

PURPOSE:To reduce number of colors unable to be detected with respect to a light source by arranging light emitting means close to each other. CONSTITUTION:Three kinds of LED1, LED2, LED3 are arranged on a board 4 as shown in Figure, and a rod lens 5 is arranged above them. The peak wavelengths of the LEDs 1, 2 are different but close to each other and the LEDs 1, 2 are arranged close to each other. The light emission distribution is overlapped through the close arrangement and a color of a light source is not almost different froth the location. When a GaAlP 635nm LED is adopted for the LED 1 and a GaAsP 660nm LED is adopted for the LED 2, the spectral distributions of the two kinds of LEDs 1, 2 are partly overlapped as if a LED with a light emission spectral distribution as wide as nearly twice were employed. As a result, number of colors unable to be detected is reduced.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】この発明は原稿上の情報を読み取
って、電気信号の形で得るカラー画像読み取り装置に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image reading apparatus for reading information on a document and obtaining it in the form of an electric signal.

【０００２】[0002]

【従来の技術】カラー画像読み取り装置の一方式として
赤／緑／青の３色の光源を順次切り替えて、カラー原稿
を照射して一個のモノクロ用センサで順次読み取る方式
が特開昭５４−８１７１５で開示されている。この方式
は残光のある蛍光灯を読み取りライン毎に３色順次切り
替え制御するために読み取り時間が比較的長くかかると
いう問題はあるが、安価な割に高精細な画像データが得
られるカラー画像読み取り方式として各種製品化されて
いる。この方法の改良案として、赤と緑の光源に効率が
著しく改善されて来た発光ダイオード（以下ＬＥＤと称
する）を使用する提案がなされている。この改良案は機
器の小型化／省電力化に寄与し、今後センサの高感度化
が更に進めば残光もなく高速化にも寄与可能な将来的に
有力な方法である。2. Description of the Related Art As one method of a color image reading apparatus, there is a method of sequentially switching light sources of three colors of red / green / blue, irradiating a color original and sequentially reading with a single monochrome sensor. It is disclosed in. This method has a problem that the reading time is relatively long because the fluorescent lamp with afterglow is controlled to sequentially switch three colors for each reading line, but it is inexpensive, but it is a color image reading method that can obtain high-definition image data. Various products have been commercialized as methods. As a proposal for improving this method, it has been proposed to use a light emitting diode (hereinafter referred to as an LED) whose efficiency has been remarkably improved for red and green light sources. This improvement plan is a promising method in the future, which contributes to downsizing / power saving of the device, and can contribute to high speed without any afterglow if the sensitivity of the sensor is further enhanced.

【０００３】[0003]

【発明が解決しようとする課題】しかしながら、上記従
来例においては、図５に示すように、ＬＥＤの発光スペ
クトルは青色蛍光灯の発光スペクトルに比べて発光スペ
クトル幅が非常に狭く、読み取り不可能な色帯域が有る
という欠点がある。赤色として６６０ｎｍのＧａＡｌＡ
ｓ−ＬＥＤ、緑色として５６７ｎｍのＧａＰ−ＬＥＤ、
青色として蛍光放電管を使用したカラー画像読み取り装
置で７０数種のカラーパッチを使用して測色した平均色
差は色差補正後、白色蛍光灯の場合の約７、ハロゲンラ
ンプの場合の約２強に比べて１４近いという非常に大き
な値を示した。However, in the above-mentioned conventional example, as shown in FIG. 5, the emission spectrum of the LED has a very narrow emission spectrum width as compared with the emission spectrum of the blue fluorescent lamp, which makes it unreadable. It has the drawback of having a color band. 660 nm GaAlA as red
s-LED, 567 nm GaP-LED as green,
The average color difference measured using 70 or more color patches with a color image reading device that uses a fluorescent discharge tube for blue is about 7 for white fluorescent lamps and about 2 for halogen lamps after color difference correction. It showed a very large value of about 14 compared to.

【０００４】この発明は、上記のごとき事情に鑑みてな
されたものであって、その目的とするところは、光源と
して発光スペクトル半値幅の狭いＬＥＤを使用しても、
読み取り不可能な色を少なくする事が可能なカラー画像
読み取り装置を提供しようとするものである。The present invention has been made in view of the above circumstances, and an object thereof is to use an LED having a narrow emission spectrum half width as a light source.
It is an object of the present invention to provide a color image reading device capable of reducing unreadable colors.

【０００５】[0005]

【課題を解決するための手段】かかる目的を達成するた
めに、本発明は複数色の光源を順次切り替え、該光源に
よって照射された原稿からの反射光を光電変換素子に結
像させて電気信号の形でカラー画像を得るカラー画像読
み取り装置において、前記光源の少なくとも１色に関し
て、ピーク発光波長が近いが異なる少なくとも２種の発
光手段を近接して配置したことを特徴とする。In order to achieve the above object, the present invention sequentially switches light sources of a plurality of colors and forms an image of reflected light from a document illuminated by the light sources on a photoelectric conversion element to generate an electrical signal. In a color image reading apparatus for obtaining a color image in the form of, at least two kinds of light emitting means having different peak emission wavelengths but different peak emission wavelengths are arranged in proximity to at least one color of the light source.

【０００６】[0006]

【作用】本発明によれば、発光ピーク波長が異なるが近
接した発光手段を複数近接させて配置させるので、発光
スペクトル半値幅が狭い発光手段でも発光スペクトル半
値幅が２倍程度広い光源と同じような効果を得ることが
できる。According to the present invention, a plurality of light emitting means having different emission peak wavelengths but close to each other are arranged close to each other. Therefore, even a light emitting means having a narrow emission spectrum full width at half maximum is similar to a light source having a wide emission spectrum half width at about twice. It is possible to obtain various effects.

【０００７】[0007]

【実施例】以下、図面を参照して本発明の実施例を詳細
に説明する。Embodiments of the present invention will now be described in detail with reference to the drawings.

【０００８】図１に具体的な一実施例を示す。６が本発
明が適用される赤と緑の２色のＬＥＤ光源である発光ダ
イオードユニット、７が青色の蛍光管、８が原稿１１か
らの反射光をモノクロセンサ９に結像するレンズＳＬＡ
で、１０がこれらを保持結合する読み取りユニットのホ
ルダである。FIG. 1 shows a specific embodiment. Reference numeral 6 is a light emitting diode unit which is an LED light source of two colors of red and green to which the present invention is applied, 7 is a blue fluorescent tube, and 8 is a lens SLA for focusing reflected light from an original 11 on a monochrome sensor 9.
Reference numeral 10 is a holder of the reading unit for holding and coupling them.

【０００９】図２でこの発光ダイオードユニット６を詳
しく説明する。図２（Ａ）は正面図、（Ｂ）は側面図で
ある。基板４上に３種のＬＥＤとして、ＬＥＤ１／ＬＥ
Ｄ２／ＬＥＤ３が図のように並べられ、その上部に棒状
のレンズ５が配置されている。此で、ＬＥＤ１とＬＥＤ
２とがピーク波長が異なるが近い２種のＬＥＤであっ
て、近接配置されている。この様に近接して配置すれば
光照射分布が重なり、場所によって光源の色がほとんど
違わないようにすることができる。此で、ＬＥＤ１がＧ
ａＡｌＰの６３５ｎｍのＬＥＤで、ＬＥＤ２がＧａＡｓ
Ｐの６６０ｎｍのＬＥＤであれば、図４に示すようにこ
の２種のＬＥＤ１，２の分光分布は一部重なりあたかも
発光スペクトル分布が約２倍広いＬＥＤのように見なす
ことが可能となる。結果として、検出不可能な色を減ら
すことが可能になる。この複数のＬＥＤは６００ｎｍ台
の赤色ではなく５００ｎｍ台の緑色の２種のＬＥＤでも
良い。また、両方で４種のＬＥＤを使用すればさらに不
感色を減らせることは言うまでもない。ＬＥＤの並べ方
は図３のように１列に並べることもでき、また複数のＬ
ＥＤを単一個にまとめてもよい、他にも千鳥とか類似の
方法は色々有るがここでは省略する。The light emitting diode unit 6 will be described in detail with reference to FIG. 2A is a front view and FIG. 2B is a side view. LED1 / LE as three types of LEDs on the substrate 4
The D2 / LEDs 3 are arranged as shown in the figure, and the rod-shaped lens 5 is arranged on the upper part thereof. Here, LED1 and LED
2 and 2 are two types of LEDs that are close to each other but have different peak wavelengths, and are closely arranged. If they are arranged close to each other in this way, the light irradiation distributions overlap each other, and it is possible to make the color of the light source hardly differ depending on the place. Here, LED1 is G
aAlP 635nm LED, LED2 is GaAs
In the case of a P 660 nm LED, the spectral distributions of the two types of LEDs 1 and 2 can be regarded as an LED whose emission spectrum distribution is about twice as wide as shown in FIG. As a result, it becomes possible to reduce undetectable colors. The plurality of LEDs may be two kinds of LEDs of a green color of a 500 nm range instead of a red color of a 600 nm range. Needless to say, the use of four types of LEDs for both can further reduce the insensitive color. The LEDs can be arranged in a row as shown in FIG.
The EDs may be combined into a single unit, and there are various other methods similar to the staggered method, but the description thereof is omitted here.

【００１０】[0010]

【発明の効果】以上説明したことから明らかなように、
本発明によれば、例えば発光手段を近接して配置するこ
とによって、光源に関して不感色を減少させることがで
きる。As is apparent from the above description,
According to the present invention, it is possible to reduce the insensitive color of the light source, for example, by arranging the light emitting means in close proximity to each other.

【００１１】[0011]

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明のカラー画像読み取り装置の一実施例の
断面図である。FIG. 1 is a sectional view of an embodiment of a color image reading device of the present invention.

【図２】（Ａ）は同実施例のＬＥＤ光源の正面図、
（Ｂ）は側面図である。FIG. 2A is a front view of the LED light source of the same embodiment,
(B) is a side view.

【図３】他のＬＥＤ光源の正面図である。FIG. 3 is a front view of another LED light source.

【図４】同実施例の作用効果説明のための特性図であ
る。FIG. 4 is a characteristic diagram for explaining a function and effect of the embodiment.

【図５】従来のＬＥＤ光源の発光特性を説明するための
特性図である。FIG. 5 is a characteristic diagram for explaining emission characteristics of a conventional LED light source.

【符号の説明】[Explanation of symbols]

６ 発光ダイオードユニット ５ 棒状レンズ ＬＥＤ１，ＬＥＤ２，ＬＥＤ３ 発光ダイオード 6 Light emitting diode unit 5 Rod lens LED1, LED2, LED3 Light emitting diode

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 複数色の光源を順次切り替え、該光源に
よって照射された原稿からの反射光を光電変換素子に結
像させて電気信号の形でカラー画像を得るカラー画像読
み取り装置において、前記光源の少なくとも１色に関し
て、ピーク発光波長が近いが異なる少なくとも２種の発
光手段を近接して配置したことを特徴とするカラー画像
読み取り装置。1. A color image reading apparatus that sequentially switches light sources of a plurality of colors, forms reflected light from a document illuminated by the light source on a photoelectric conversion element, and obtains a color image in the form of an electrical signal, wherein the light source is a light source. The color image reading device is characterized in that at least two kinds of light emitting means having different peak emission wavelengths but different in at least one color are arranged close to each other. 【請求項２】 請求項１において、前記近接位置させた
発光手段と他の発光手段とを交互に配置したことを特徴
とするカラー画像読み取り装置。2. The color image reading device according to claim 1, wherein the light emitting means and the other light emitting means which are located close to each other are alternately arranged.