JPS63177677A - Image pickup device - Google Patents

Abstract

PURPOSE:To prevent the early deterioration of a colorimetric means due to an external light by providing a light shielding means, which can be released, for light shielding the colorimetric means. CONSTITUTION:Because a slide cover 2 is made to slide and to shield the light of a colorimetric window 6 at the time when a camera is non-use, a color filter 22 is prevented from the early deterioration so that the service life of it is lengthened. Besides, the cover 2 can be constituted simply because it is shared with the cover to cover a photographing lens 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an imaging device, in particular, to an imaging device that electrically captures an optical image of a subject.
This relates to an imaging device that converts to No. A.

(Prior art) An optical image of a subject is converted into an electrical signal using a COD (charge-coupled device), an iJ body image sensor, or an image pickup tube, and the signal is displayed on a CRT (cathode ray tube). Video cameras or still video cameras that record on recording media such as magnetic data 1 or magnetic disks are already in practical use.

In this type of imaging device, light from a subject is made to enter the image sensor through a color filter to obtain a color signal, but if the color filter's transmission characteristics (color temperature) for the wavelength of light change. , different color signals will be output even for the same subject.

For example, even if a subject is perceived as white under sunlight (around 5,000), when viewed at an F of a tungsten lamp light source (around 2,900), it will be perceived as white when viewed at a human [1]. The color signal from the image sensor is output as an object whose color is considerably biased toward red.

By the way, in order to prevent the above-mentioned phenomenon, in order to obtain color reproducibility that is substantially the same as seen with the human eye under any light source, the color temperature of the light source is adjusted to match the color temperature of the light source.
The so-called "white balance: A adjustment" is performed, which changes the mixing ratio of the primary colors of the video signal obtained from the image sensor.
There is C. In order to adjust the white balance, light from the illumination light source of the object is introduced into a light receiving element through a filter of primary colors or three primary colors, and color temperature is calculated based on the output.

Here, some color filters for color temperature measurement such as those shown in "-" use pigments made from inorganic materials, but
Due to its light wavelength transmission characteristics, it is generally used in dyes made from organic materials.

(Points to be solved by the invention) However, when using the above organic dye,
As shown in Figure 3, the wavelength transmission characteristic diagram of a colorimetric color filter shows that in its initial stage, it exhibits extremely excellent color transmission characteristics as shown by the solid line, but when exposed to external light for a long period of time, the characteristics change. For example, as shown by the broken line in the figure, the red filter tends to transmit more of the wavelength component of the line.

Therefore, when such a characteristic change occurs, correct color measurement cannot be performed, and as a result, there is a drawback that it becomes impossible to accurately perform the correct white balance adjustment as described in l) η.

The present invention has been made by focusing on the problems of the conventional example as described below, and provides a means for correct white balance adjustment over a long period of time even when using this type of colorimetric color filter. We aim to provide 11 items.

[Means for solving problems]

Therefore, the present invention attempts to achieve the above object by providing a light shielding means for always shielding light except when necessary on the front surface of a colorimetric color filter or the like.

[Effect]

With the configuration shown below, the colorimetric color filter is
Since light is not irradiated except when necessary, early deterioration of the filter can be prevented, and correct white balance adjustment can be performed over a long period of time.

〔Example〕

Hereinafter, the present invention will be explained based on examples.

FIGS. 1(a) and 1(b) are perspective views of an embodiment in which the present invention is applied to a still video camera. FIG. 1(a) is when the slide cover is released (during imaging), and FIG. The status of each is shown below. Furthermore, FIG. 2 is a block diagram showing an outline of the flow of imaging signals of this still video camera.

(Structure) In FIG. 1, 1 is a camera body, and 2 is a light-shielding slide cover provided as an embodiment of the present invention. Also, 3 is the photographing lens, 4 is the finder, and 5 is the photometry (AE).
River sensor, 6 is light receiving element 23 for white balance color measurement
Diffusion plates 7a and 7b arranged in the m1 section of (Fig. 2)
is the automatic fish collection (AF) river distance measurement window, and 8 is the trigger button.

Next, in FIG. 2, 11 is an exposure control mechanism consisting of an aperture and a shutter used in the lens 3;
is a CCD, 13 is a luminance/color signal separation circuit, 14 is a signal processing circuit for creating a color difference signal and a luminance signal, 15 is a modulator circuit for creating a signal form for magnetic recording, which will be described later, and 16 is an amplifier. A magnetic head 17 is moved along the radial direction of the magnetic disk 18 by a head feeding mechanism (not shown). A magnetic disk 18 serving as a recording medium is rotated at a constant speed by a spindle motor 19.

Next, 5 is an exposure control light receiving element, and the light receiving element /-5
In response to the output, the aforementioned aperture or shutter 11 is controlled via the exposure control circuit 21, and proper exposure is performed for the CCD 12. A system controller 2o controls the camera function and recording function as a whole (detailed explanation will be omitted since this is well known).

(Operation) In Fig. 1(a), press the tributton 8 and press the camera 1
When the operation is started, the diaphragm/shutter 11 is activated in the exposure control circuit 21, and a subject image is formed on the CCD 12. The subject image signal from the CCD 12 is sent to the magnetic disk by the magnetic head 17 via each circuit 13, 14, 15, 16. 8 as a one field or one frame television signal.

Here, 22 represents the diffuser plate 6 and the colorimetric photodetector F23.
This is a color filter for the light receiving element 23 disposed between them. That is, subject light source light is incident on the light receiving element 23 via the diffuser plate 6 and the color filter 22, the color temperature of the light source is measured, and a color (difference) signal is generated in the signal processing circuit 14 based on this output signal. be adjusted.

Here, as mentioned above, if the color filter 22 is exposed to light for a long time, the original wavelength transmission characteristics will change.
The light-receiving element f23 cannot perform accurate coloring.

Therefore, in the camera of this embodiment, when the camera is not in use, the slide cover 2 can be moved from the state shown in FIG.
) By sliding the color filter 22 in the state shown in the figure and blocking light from at least the colorimetric window 6, the color filter 22 is prevented from deteriorating in appearance and its life is extended. Incidentally, since the cover 2 is also used as a cover for covering the photographing lens 3, the structure can be made into a cylinder. Such a cover may be opened and closed electrically or by a spring or the like.

(Second Embodiment) FIGS. 4(a) and 4(b) are explanatory views of the main parts of another embodiment of the present invention. (a) shows the state when light is blocked, and (b) shows the state when light is removed. shows. Reference numerals 6, 22, and 23 denote a diffuser plate, a color filter, and a colorimetric light-receiving element, which are the same (equivalent) components as in FIG. 1.2, respectively. On the side of this embodiment, a light shielding member 31 that is rotatable around a shaft 32 is provided, and the light shielding member 31 is connected to the electromagnetic plunger 3.
3, as shown in Figure (a), the diffuser plate 6,
It is configured so that the color filter 22 and the colorimetric light receiving element 23 can be shielded from light, or can be unshielded as shown in FIG.

FIGS. 5(a) to 5(6) show operation timing charts of each part when the above mechanism is applied to a still video camera. In (a), when the camera is started by pressing the trigger button 8 (Fig. 1), the light shielding member 31 is released by the solenoid 33 being energized at time tbl, as shown in (b), and the light shielding member 31 is released as shown in Fig. 4 (Fig. 4). In the state b), the colorimetric light receiving element 23 is irradiated with the light source light. Next, an exposure calculation is performed and the CCD 12 (FIG. 2) is exposed to light between time points tcINtc2 shown in FIG. 5(C).

FIG. 5(d) shows the l field and vertical blank, and as shown in FIG. 5(e), the next field (1-+
~t02), the subject information is stored on the recording medium 18 (second
recorded on magnetic disks).

When these exposures are completed, the time t shown in FIG. 5(b)
At b2, the light shielding member 31 returns to the light shielding state shown in FIG. 4(a) by the return spring (not shown) of the solenoid 33, and the colorimetric filter 22 and other parts are shielded from light. The same effect can be obtained.

(Third Embodiment) FIGS. 6(a) and 6(b) are explanatory views of the main parts of an embodiment in which the present invention is applied to a movable mirror-eye reflex type video still camera. ) is the light shielding state, (b)
indicates the light-shielding state; the diffuser plate, color filter, and colorimetric photodetector Y- are the same as in the description; symbol 6, 22.23
It is expressed as

In this embodiment, the light shielding member 31 in FIG. 5 of the second embodiment is driven by a movable mirror drive member 43 instead of being rotated by the plunger 33. That is, in FIG. The mirror 41 is rotatable around an axis 42, and at the object observation position,
The state shown in Fig. 6 (a) is taken, and the state shown in Fig. 6 (b) is taken at the photographing position.
) state.

These operations are performed by the mirror drive lever 43 using a quick return mechanism (not shown), and the mirror drive lever 43 is rotated counterclockwise from the state shown in FIG. , the mirror 41 and the light shielding member 31 are brought into the state shown in Fig. (b) via pins 43a and 43b respectively grafted onto both ends of the lever 43, and when the photographing is completed, the state shown in Fig. (a) is returned. It is configured to return to the state of. The operation timing of each part is
According to FIG. 5 in the embodiment, the part shown in FIG. can get.

In addition to the above-mentioned first to third embodiments, although not shown in the drawings, there are operating members such as a diaphragm that starts operating upon exposure in a photographing operation, or a tape in a movie type video camera. The light shielding member may be configured to be driven in conjunction with loading or the start of recording.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to prevent early deterioration of the colorimetric means due to external light, thereby making it possible to perform correct white balance adjustment over a long period of time.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are perspective views of an embodiment of the still video camera according to the present invention, and FIG. 2 is a block diagram of the same camera No. 5. Fig. 3 is a wavelength transmission characteristic diagram of the colorimetric color filter, Figs.
Figures (a) to (e) are timing charts of the trough operation of the still camera, and Fig. 6 is an explanatory diagram of the main part operation of the third embodiment. 1... Force, camera body 2... Slide cover (light shielding member) 3...
...Photographing lens 6------Color measurement window 8---Trigger button 22---Color filter 31---Light shielding member

Claims (3)

[Claims] (1) An imaging device having a colorimetric means for detecting color temperature, characterized in that the light shielding means for shielding the colorimetric means is removable. (2) The imaging device according to claim 1, wherein the light blocking means is configured to release the light blocking in conjunction with the imaging operation of the imaging device. (3) The imaging device according to claim 1, wherein the light shielding means is configured to shield a photographing lens of the imaging device together with the colorimetric means.