JPS58125867A - Color sensor - Google Patents

Abstract

PURPOSE:To make output voltage/incident light intensity of respective elements to nearly the same when the color sensor is to be produced by providing thin film type photosensitive elements having respectively a filter film on the face on one side of a transparent substrate, and by forming photo active layers consisting of amorphous Si facing to the elements thereof on the face on another side by a method wherein the areas of the respective elements are made to differ corresponding to photosensitivities of the respective elements. CONSTITUTION:The thin film type photosensitive elements 12R, 12G, 12B having filters 13R, 13G, 13B of red, green, blue are formed respectively on the face on one side of the transparent substrate 11 consisting of glass, plastics, etc., of about 0.3mm. thickness. Moreover laminated bodies consisting of respectively a first transparent electrode 14 of tin oxide or indium.tin oxide, a photo active layer 15 of amorphous Si of about 1mum thickness, a second Al electrode 16 are provided on the face on another side of the substrate 11 facing to the elements thereof. At this time, the photo active layer 15 is constituted of a P type layer 15a, an I type layer 15b and an N type layer 15c. At this construction, the photosensitive areas of the respective elements 12R, 12G, 12B are made to differ mutually corresponding to respective photosensitivities, as embodiment thereof, the ratio of areas are preferably made as 1.9:2:2.9.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color sensor using an amorphous semiconductor as a photoactive layer.

Color sensors using single crystal silicon for the photoactive layer are already known. Its basic configuration is as shown in Figure 1.
A plurality of photodiode flL regions (2), (3), and (4) are provided on the surface of the single crystal silicon substrate (1), and color filters such as a red filter (5) and a green filter (5) are formed on each of these regions. 6) and a blue filter (7), and an infrared cut filter (8) is placed on top of it.In the prayer sensor, when visible light enters the substrate (11) through each filter, the incident visible light is Depending on the color of the light, if it is red, it is placed in the diode area +21, if it is on the edge, it is placed in the diode area (3), and if it is written, it is placed in the diode area (4).
) signals are output respectively.

The photosensitivity characteristics of single-crystal silicon itself exhibit a peak in the infrared region, as shown by the curve IAK in Figure 2, while the red filter (5) exhibits a transparent peak in the red band, but its band characteristics are broadened. is normally attenuated even into the infrared region.

Therefore, when using single-crystal silicon for the photoactive layer, simply passing it through a red filter will not allow the photodiode region* (21
is strongly sensitive to attenuated but incident infrared light, depending on the photosensitivity characteristics of the single crystal silicon itself, making it impossible to detect accurate color information. The infrared cut filter (8) in the above-mentioned conventional color sensor is provided to remove such incident infrared light, and is indispensable. The present invention has been made in view of the above points, and the present invention will be described below with reference to embodiments. explain.

FIG. 6 shows a color sensor Ql sensitive to red, edge, and blue colors according to this embodiment. This color sensor (11 digits thickness 0
．． A light-transmitting substrate 11)K made of glass, plastic, or the like is provided and includes a running path 1, a second, and a fifth thin-film photosensitive elements (12R), (12G), and (12B). Each of these photosensitive elements has its own color filter film provided on one main surface of the substrate aυ, that is, the first photosensitive element (12R
) K is the red filter film (13R), the second photosensitive element (12
G) includes a green filter II (13G) and a fifth photosensitive element (
12B) has a blue filter [1 (15B). As each filter membrane, WRATTEN GELATEN FILTER manufactured by Eastman Kodak is suitable, and as the red filter membrane (15R), WRATTEN GELATEN FILTER manufactured by Eastman Kodak Company is suitable.
, M58 is used as the green filter film (13G), and M47B is used as the blue filter l1l (15B), and these are fixed onto the substrate Ql) with a transparent resin adhesive such as Kanagpalsan. Ru.

1st to 5th photosensitive elements (12R), (12G), (12B
) are further provided on the other main surface of the substrate αυ.
It includes a laminate of an electrode film I, a photoactive layer αe, and a second electrode film, and these laminates individually face the filter films of the respective photosensitive elements.

The first electrode layer is made of a transparent conductive material such as diluted tin or indium/tin oxide, and the second electrode @QE9 is made of aluminum or the like.

The photoactive layer α9 is made of an amorphous silicon semiconductor with a thickness of about 1 μm, and its details are shown in FIG. To explain this in more detail along with the manufacturing method, the substrate Uυ on which only the first electrode I of each element (12R), (12G) and (12B) has been formed is placed in a reaction chamber, and placed in an atmosphere consisting of sulfur gas and impurity gas. A P-type layer (1) made of amorphous silicon is formed on the first electrode Q41 by glow discharge at
5m), a summer type layer (15b) and an N type layer (15c) are sequentially deposited to form a photoactive layer a→. The deposition S area can be limited to a predetermined portion by using a mask. Incidentally, the formation of an amorphous silicon diode by glow discharge itself is well known, as disclosed in Japanese Patent No. vB53-57718.

In the above color sensor Ql, each color filter (1SR)
, (13G), and (15B), if the light incident from these filters includes red color, it passes through the red filter (11) and the substrate aυ to the first photosensitive element (1
2R) K enters and generates free carriers in the main Kl type layer (15b) within the device. These free carriers are collected at the first and second electrodes (lfeK), and a voltage is generated between the two electrodes.Similarly, when the incident light contains green color and blue color, the second photosensitive element (12G), a voltage is generated between the first and second electrodes a◆ and Qfe in the third photosensitive element (12B).Therefore, by detecting these voltages, the color of the incident light can be detected.

As shown by curve B in FIG. 2, the photosensitivity characteristics of amorphous semiconductors mostly fall within the visible light region. For this reason, in the color sensor of this embodiment, even if infrared light enters through the red filter (15R), it is hardly detected, and therefore accurate color information can be obtained without using the conventional infrared filter. can be detected. Moreover, in the color sensor Ql of this embodiment, each color filter (15R), (15G) (13B)
Since it is attached to the surface of the substrate opposite to the photoactive layer a9, the photoactive layer Q9 will not be damaged during attachment.

The embodiment of the present invention aims to further improve the color detection accuracy of such an excellent color sensor (lI).In other words, the photosensitivity characteristics of the amorphous semiconductor are similar to the visible light aX as described in Figure IN2. Although the band is within the range, it is not flat and has a peak around 550 nm as shown in the figure.
The transmittance of curves (17R) and (17B) are also shown in Figure 5.
As shown in G) and (17B), they are not the same, and in particular, that of the red filter film (15R) is the largest. For this reason, the first
~38th optical element ((12R), (12G), (12B)
The photosensitivity is also different, and even if the intensity of human radiation is the same, different detection outputs will be generated.

The most significant feature of the embodiments of the present invention is that each element (12R
)(12G)(12B) increases in accordance with the photosensitivity of each element, and the element with the highest photosensitivity has the smallest light receiving area. More specifically, the first, second, @3 photosensitive elements (12k), (12G)
, (12B) The ratio of the light receiving area is approximately t9:2:2.9
As a result, the photosensitivity (output voltage/incident light intensity) of each element becomes the same, and color detection is performed with good accuracy.

In the above embodiment, each element (12R), <12G), (1
2B) The photoactive layer Q5 is of the photovoltaic type, including a PIN junction, and is, for example, approximately 5 μm thick! It is also possible to form only amorphous silicon and change it to a photoconductive type photoactive layer. In this case, as shown in FIG. 6, a pair of electrodes (16m) and (16b) may be attached to the surface of one photoactive layer.

In addition, in the above embodiment, the photoactive layer is $0 and the first and second electrodes are $0.
04) and (+6) are both separated for each element, but the photoactive layer Q! Each element (12
R), (12G), and (12B), or alternatively, either the first electrode @I or the second electrode film can be provided continuously to each element without having to be separated. It is also possible to provide a photoactive layer α made of an amorphous semiconductor! Since the thickness of 9Vi is extremely small, there is almost no talostoke between each element even if it is successively provided in each element as described above.

In addition, instead of the amorphous silicon used in the photoactive layer (1) of the above embodiment, other materials such as amorphous silicon cannibale may be used, and it is also possible to mix polycrystals or microcrystals into a part of the photoactive layer. It is.

Also, the number of photosensitive elements can be increased or decreased as appropriate depending on the number of events.

As is clear from the above description, according to the present invention, it is possible to realize a color sensor that does not require an infrared cut filter, to which other color filters can be easily attached, and to improve its color detection accuracy.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional example, Fig. 2 is a photosensitive characteristic diagram, Fig. 3 A is a plan view of an embodiment of the present invention, Fig. 3 BijlilB
-Blllrljl, Figure s ch Same C-C [Figure m, 4th
Enlarged sectional view of the company number, gI! Figure 15 is a transmission characteristic diagram, No. 6
The figure is a sectional view of a main part of another embodiment. on-atii, (12A), (12B), (12C
)-41, second and third photosensitive elements, α...photoactive layer. Figure 1 Figure 2 Tears & (rL size

Claims (1)

[Claims] +11 A plurality of thin-film photosensitive elements provided on a light-transmitting substrate, each of which includes a color filter film unique to a line element provided on one main surface of the substrate, and a color filter film unique to the line element provided on one main surface of the substrate, and a color filter film unique to the line element provided on one main surface of the substrate, and A light-inactive layer provided on the main surface and mainly composed of an amorphous semiconductor, and a laminate of electrode films individually facing each of the color filter films, and the light-receiving area of each element corresponds to the photosensitivity of each element. A color sensor featuring nine features.