JPS59143487A - Color image pickup tube - Google Patents

Abstract

PURPOSE:To reduce the B/R ratio of a color signal and to prevent color mixing due to vertical correlation error by applying the alternate arrangement of cyan stripe and light cyan stripe having higher transmissibility than the former stripe as the 2nd color filter member. CONSTITUTION:A filter obtained by superposing the 1st and 2nd color filters alternately is used for the color image pickup tube to be used for a color TV and the 1st color filter member consists of a stripe thin plate obtained by arranging colorless transparent stripe W and yellow stripe Ye alternately. The 2nd color filter 9 consists of a stripe thin plate obtained by arranging cyan stripe Cy and light cyan stripe Cy' having higher light transmissibility then the former stripe alternately. The light transmissibility of the stripe Cy' is reduced at a red R area, a crossing point between an R output and a G output is reduced from an O to O' direction and separation between both output signals is improved by the reduced quantity to prevent the color mixing due to the vertical correlation error.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention (c) relates to a color image pickup tube used in a frequency separation single tube color television camera.

Conventional Structures and Problems Generally, a color image pickup tube used in a frequency separation single-tube color television camera is equipped with a color separation color filter having a pattern as shown in FIG. 1 on its light-receiving surface. This color filter consists of first and second color filter members stacked on top of each other. The color filter member of A1 has a colorless transparent stripe W and a yellow stripe Ye.
The second color filter member is made of a striped thin plate in which colorless transparent stripes W and white stripes are alternately arranged. and,
The stripes of the first and second color filter members are /
, the two right approximately χ・j intersect each other for the first time, so the diamond-shaped area where the cyan stripe Cy and the yellow stripe Ye intersect becomes a green filter as shown in Figure 2, and the green light G
Transmit only. Further, the cyan diamond-shaped area blocks red light R and transmits blue light B and green light G, and the yellow diamond-shaped area blocks blue light B and blocks red light R and green light G.
Therefore, the color components of the signal S (n) obtained by the nth electron beam scan are as shown in (a) of Figure 3, and the color components obtained by the n'-1-1th electron beam scan are as shown in (a) of Figure 3. The color components of the signal S (n+1) obtained are as shown in FIG. 3(b).

S'(n)=(r+R/2+B/2+α(R+B)si
nωt ,,-・,-(1)S (n+1)=G+R
/2+h +a(R-B)sin(ωt+900)=(
2) And such signals S (n), S (n+v
) is processed by a color separation circuit as shown in FIG. 4, and the RY signal and BY signal are taken out from the same circuit.

The first and second color filter members are shown in FIG.
) and (b), so for each one, i, in the direction shown by the arrow in the figure,
li: By scanning the child beam, (
Color component signals as shown in C) and (d) are obtained.

means that it exists in Also, G = 'W - (R
+B), so GyY6XC)'.

Since the three primary color signals are obtained using the first and second color filter members having such a relationship, it is impossible to change the spectral characteristics of the color filter portion in order to increase only the sensitivity of a specific color component. .

On the other hand, since the white balance adjustment of a color television camera is normally carried out under illumination with an incandescent lamp of 3000 mm, the distribution of the color image pickup tube output signal tends to be on the long wavelength side, that is, on the red side. Since there are many opportunities for the RZB ratio to be greater than 1, this phenomenon is especially likely to cause vertical correlation errors, and when imaging a subject, it can cause unwanted color mixture due to false signals. This is noticeable when using a color image pickup tube that uses a light guide film with high red sensitivity.

OBJECTS OF THE INVENTION The main object of the present invention is to solve the above-mentioned conventional disadvantages by optical means.

Structure of the Invention In the color image pickup tube of the present invention, instead of the alternating arrangement of colorless transparent stripes and cyan stripes as the second color filter member, cyan stripes and light cyan having a higher light transmittance than the cyan stripes are used. An alternating arrangement with stripes is applied, and the stripes will be explained in detail below together with embodiments shown in the drawings.

DESCRIPTION OF THE EMBODIMENTS The color filter shown in FIG. 6 consists of first and second color filter portions that are arranged in a phase pattern, and is provided on the outer surface of the photoconductive film of the image pickup tube to perform color separation. The points are the same as before. First color filter section, colorless transparent stripe W,! : The second color filter member is made of a thin plate with a striped pattern in which yellow stripes AY are alternately arranged and light cyan stripes AY having a higher light aA rate than this stripe. Pattern 7:, Keita Kashinaru. And 1. ;l': 1:I,
- The stripes of the second oak filter member intersect diagonally so as to be substantially symmetrical.

The light cyan stripes Q and / have a light transmittance close to that of the colorless transparent stripes W, but have a rhombic region Cy' that intersects with the colorless transparent stripes W and a rhombic region Ye' that intersects with the yellow stripes Ye. , the transmission of the red light R is blocked by ΔR. Therefore, if R-ΔR=R/, the color components of the signal obtained by scanning the nth electronic beano will be as shown in FIG. 7(a), and n11
The color components of the signal obtained by the second electron beam scan are as shown in FIG. 7(b).

As a result, as shown in Table 1, the Y output becomes smaller by ΔR/2 and the R output becomes smaller by ΔR, compared to the case using conventional color filters. Since the B output is unchanged from the conventional one, the R/B ratio decreases and approaches 1, and the occurrence of color mixture due to false signals is reduced.

Furthermore, white balance adjustment in color television cameras is more often performed under a constant Y output light amount than under a constant input light concentration, that is, a constant lens aperture. , Even though the RZB ratio is reduced, the color difference signal RY for a red object can be increased, and the red object can be imaged more vividly than before.

To explain the point in detail with reference to Tables 1 and 2, when setting the white balance with a constant Y output light amount, the lens aperture of the present invention is twice the sensitivity ratio compared to the conventional one, that is, ( 1+ΔR/2Y') times,
B output is twice as much as before. Then, in order to make Rw = Bw = Y in white balance adjustment, KR ratio output gr
Since the B output is multiplied by gr, the red color difference signal R
w - Y becomes a dog, and the color: 1 o 1 degree becomes higher. Also,
Although the blue color difference signal Bw-Y becomes small and the vividness of the late subject image is slightly suppressed, the transition to such color reproduction characteristics is preferable in terms of visibility.

(Leaving space below) Table 1 Table 2 Light cyan stripe Qy Since the light transmittance of L is low in the red region R as shown in Figure 8, the intersection of R output and G output is This decreases from the conventional O to 0', and the separation of the Ryokawa force signals becomes that much better. In addition, as shown in Figure 1o, the Y output as a luminance signal decreases in the red region, so as mentioned above, the red color difference signal R-Y increases, and the foaminess (and brightness) of red improves. do. In addition, the 9th
The broken lines in the figure and FIG. 10 indicate the characteristics when a conventional color filter is used.

Color reproduction when the color per chart is fully extended! 1.〒
Figure 11 shows the first life in a vector diagram using Combutan Mille Noyon. Here, 01IJ indicates the value when a conventional color filter is used, the * mark indicates the value when the present invention is applied, and the X mark indicates the electrical ideal value. From this, it can be seen that the phases of red R and cyan ay approach the ideal one, and the firing degree also improves. Furthermore, the compatibility of green G and magenta Mg is also improved. Furthermore, the phase of yellow Ye is rotated more than that of red R, although only slightly, and as a result, the skin color reproduction is improved to a warmer one.

According to the present invention, the Y sensitivity doubles to 1//, but the difference is very small, and even if the Y sensitivity decreases, the amount of chroma (degree of coloration) increases, so the effective sensitivity There is almost no decline.

Effects of the Invention As described above, in the color image pickup tube of the present invention, R/B
Since the ratio can be reduced, color mixing due to vertical correlation errors can be prevented. In addition, good color reproducibility is achieved (1), especially in R
Since the phase of can be brought close to the ideal value, it can be applied to a P A L ) j type television camera that does not require phase adjustment, and a particularly excellent effect can be obtained. Furthermore, since the RLY color difference signal is increased, the degree of amplification of the chroma signal can be suppressed to a low level, and the red shading can be prevented, which is an excellent effect.

[Brief explanation of drawings]

Figure 1 is an enlarged plan view of a part of the color filter of a conventional color image pickup tube, Figure 2 is a light transmittance characteristic diagram of the same color filter, and Figure 3 (a), Φ) is an electron beam diagram of the color filter of the same color image pickup tube. A diagram showing the color components of the output signal obtained by beam scanning,
Figure 4 is a block diagram of the color separation circuit, Figures 5 (a) to (d)
) is a diagram showing the relationship between the color filter and the color components of the signal, FIG. 6 is an enlarged plan view of a portion of the color filter of a color image pickup tube in which the present invention is implemented, and FIGS. 7(a) and (b)
) is a diagram showing the color components of the output signal obtained by electron beam scanning of the same color image pickup tube, Figure 8 is a special light transmittance diagram of the same color filter, and Figures 9 and 10 are diagrams of the color image pickup tube of the same color filter. FIG. 11, a characteristic diagram showing output signal components, is a color reproduction characteristic diagram when a color par chart is imaged by the same color image pickup tube. Name of agent: Patent attorney Toshio Nakao and one other partner
2 Figure 3 4 Figure 5 Figure Cα〕(b) Figure 6 Figure 7 Figure 8 Figure 8 Figure 9 Figure 10 Figure 11 ＼ Kinuty -B -Y 事し） X

Claims (1)

[Claims] The color filter for color separation disposed opposite to the light receiving surface is composed of first and second color filter members, the first color filter member is composed of a striped thin plate in which colorless transparent stripes and yellow stripes are alternately arranged, The second color filter member has a pattern in which cyan stripes and light noanth I-lives having a higher light transmittance are arranged in an intersecting 1'L pattern. A color imaging tube characterized in that the first and second color filter members are overlaid so that their respective stripes intersect diagonally.