JPH0348582A - Still video camera - Google Patents

Abstract

PURPOSE:To accelerate write and erasure operations by supplying high voltages for write and erasure from a camera main body side to an external memory when the fact that no booster circuit is incorporated in the external memory is detected at the camera main body side. CONSTITUTION:A memory card 8 is formed in card type external shape freely detachable on the camera main body, and incorporates an EEPROM inside. Information to discriminate the presence/absence of the booster circuit at a prescribed address for discrimination of booster circuit is stored in the EEPROM, and when the memory card 8 is loaded on the main body, address data is read. When read data is discriminated and the incorporation of the booster circuit in the memory card 8 is discriminated, power supply from a power source circuit 11 at the camera main body side to the memory card 8 is cut off. When no booster circuit is incorporated, the high voltages for the write and the erasure on the memory card 8 are supplied from the power source circuit 11 at the camera main body side.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a still video camera, and more particularly to a still video camera configured to store digital image signals in a PROM that is written and erased by applying a high voltage.

Conventional technology> In recent years, in place of conventional film cameras, cameras convert optical image signals from a subject into electrical image signals using an image sensor.
! Still video cameras have been developed that store electric image signals in a memory equivalent to film, and the electric image signals stored in the memory can now be played back and viewed on a monitor or printed as hard copies using a printer. ing.

A magnetic disk is generally used as memory for such still video cameras, and in this case, for example, an optical image signal obtained by passing through an optical lens is photoelectrically converted by an image sensor such as a CCD, and the image is converted into an image by the conversion. The resulting electrical image signal is subjected to analog processing such as color separation, gamma correction, line sequentialization, and FM modulation, and then electromagnetically converted using a magnetic head and recorded on a magnetic disk. Also, during playback, the magnetic signals recorded on the magnetic disk are converted into electromagnetic signals, processed analogously, and displayed on the monitor. However, in this method of magnetically recording analog signals on a magnetic disk, analog processing of signals and t1
Since it requires IF conversion, signal deterioration is likely to occur;
Also, the camera. Both playback machines require a rotating drive mechanism for the magnetic disk, which inevitably increases the size and cost.
Regardless of whether it is used for business purposes or for commercial use, this is a cause of delay in its widespread use for consumer use. In view of this, the applicant has developed a device in which a digital signal obtained by A/D converting an electrical image signal obtained by an image sensor is stored in a semiconductor memory configured in the form of a card that can be attached to and detached from the camera body. has been proposed (see Japanese Patent Application Laid-Open No. 59-183582), which prevents signal deterioration due to analog processing and eliminates the need for a drive mechanism like that required for magnetic disks, making it easy to use for cameras, playback, etc. It is possible to reduce the size and weight of the machine and reduce costs.

<Problems to be Solved by the Invention> By the way, the memory card used for storing digital image signals as described above uses RAM as a built-in semiconductor memory.
, EPROM, EEPROM, etc. can be used, but if RAM is used, a backup battery is required so that the memory contents can be retained even when the memory card is removed from the camera body. , EEP that does not require backup and can be erased electrically
The use of ROM is proposed.

However, EEPROM... Since it is an electrically erasable semi-permanent storage device that can be written and erased by applying a high voltage, it is necessary to apply a high voltage (...
Since the operating current for the memory card is very small, the memory card has a built-in step-up circuit from 5V to 20V and a level shifter circuit to switch the voltage between 5V and 20V. For this reason, in a still video camera that uses a memory card with a built-in EEPROM, the voltage supply to the memory card is only 5. It is being carried out. However, with the booster circuit built into the memory card or the one that supplies high voltage and switches the voltage by level switching, the delay time of boosting slows down the writing and erasing operations, so the camera body side By supplying a high voltage to the memory card from a power supply circuit provided for driving an image sensor, etc., writing and erasing operations can be made faster.

Therefore, if you provide a type of memory card with built-in EEPROM that does not have a booster circuit and configure it to supply high voltage from the camera body side, it is possible to speed up memory operation. If some devices are equipped with a circuit and some are not, there is a problem in that high voltage is supplied from the camera body to the memory card regardless of the presence or absence of a booster circuit, increasing current consumption. The present invention has been made in view of the above problems, and is based on the EEP
Memory cards with a built-in ROM do not have a built-in booster circuit, but instead supply high voltage from the camera body to speed up writing and erasing operations.However, with a booster circuit, unnecessary high voltage is supplied from the camera body. An object of the present invention is to provide a still video camera that can be prevented from being supplied with voltage.

Means for Solving the Problems> Therefore, in the present invention, as shown in FIG. A step-up circuit detection means for detecting on the main body side, and a high voltage for writing and erasing from the camera main body side when the camera body side detects that the external memory does not have a built-in step-up circuit. A high voltage supply means for supplying the external memory is provided. <Operation> According to this configuration, whether or not the external memory has a built-in booster circuit for generating the high voltage necessary for writing and erasing the PROM is detected on the camera body side by the booster circuit detection means. When it is detected that a boost circuit is built into the external memory, the boost circuit inside the memory generates high voltage for writing and erasing, so high voltage must be supplied from the camera body. This is wasteful, and high voltage is not supplied from the camera body, but with devices that do not have a built-in booster circuit, writing and erasing operations cannot be performed unless high voltage is supplied from the camera body, so high voltage is not required. The voltage supply means supplies high voltage from the camera body to the external memory, allowing writing and erasing to be performed at higher speeds than when generating high voltage with a booster circuit built into the memory. <Examples> Examples of the present invention will be described below. Figure 2 shows the system configuration of a still video camera in one embodiment. Here, the lens. Aperture, shutter. An optical image signal from an optical system 1 consisting of an optical low-pass filter, an infrared cut filter, etc. is converted into an electrical image signal by an image sensor 3 such as a COD or MOS controlled by a drive circuit 2, and this analog image is converted into an electrical image signal. After the signal is subjected to signal processing such as noise removal and T correction in an analog processing circuit 4, it is A/D converted in an analog-to-digital converter (A/D converter) 5, and then data compressed in a digital processing circuit 6. etc. are digitally processed. The digital image signal output from the digital processing circuit 6 is stored in a memory card 8 as an external memory via an ink face 7.

The memory card 8 has a card-like external shape and is configured to be detachably attached to the camera body, and has an EEP inside.
It has built-in ROM.

Further, the camera body excluding the memory card 8 is provided with a control block 9 for controlling the operations of the processing circuit 4.6, A/D converter 5, etc.
Under the control of the control block 9, the converter 5 and the like perform various processes in synchronized timing according to the clock output from the clock generator IO. Furthermore, the camera body is equipped with a power supply circuit 11 that generates a high voltage, and the high voltage from this power supply circuit 11 is supplied to the drive circuit 2 of the image sensor 3.

Here, the memory card 8 has a built-in EEPROM that is written and erased using a high voltage, and is equipped with a booster circuit for generating the high voltage for writing and erasing, and a level shifter for switching the voltage. Both built-in devices and non-built-in devices are used in combination.

If the memory card 8 has a built-in booster circuit,
Writing and erasing can be performed using a normal 5V power supply, but if the memory card 8 does not have a built-in boost circuit, it is necessary to supply high voltage from the camera body, so the memory card 8 has a built-in boost circuit. It is equipped with a booster circuit detection means to detect whether or not there is a voltage booster. As shown in FIG. 3, for example, such a step-up circuit detection means is such that a memory card 8 without a built-in step-up circuit is provided with a recess 8a on the end face of the card, and a recess 8a is provided on the camera body side to detect the presence or absence of the recess 8a. is detected by the contact switch l2.

That is, the shape of the memory card 8 is changed depending on whether it has a built-in booster circuit or not, and the difference is detected by a switch or sensor provided on the camera body side, and the detection signal is input manually to the control block 9. In addition to the recessed portion 8a shown in FIG. 3, the change in shape may be a through hole, a protrusion, a chamfered portion, or the like. Furthermore, a label or the like indicating the presence or absence of a booster circuit may be attached to the surface of the memory card 8, and the contents of the label may be read by a sensor on the camera body side.

In this case, the booster circuit detection means includes a shape or display changing section, a sensor switch for detecting this, and a control block 9.
It is structured by In addition to detecting the presence or absence of a booster circuit based on the difference in appearance of the memory card 8 as described above, it is also possible to detect the presence or absence of a booster circuit by transmitting and receiving signals between the memory card 8 and the main body. ．． For example, if information indicating the presence or absence of a booster circuit is stored in advance at a predetermined address in the EEPROM, and this information is read out when the memory card 8 is inserted into the camera body, the booster circuit can be activated. It is possible to distinguish between built-in items and non-built-in items ζ. That is, as shown in the flowchart of FIG. 4, information (code) for determining the presence or absence of a booster circuit is stored in advance at a predetermined address for determining the booster circuit, and the memory card 8 is inserted into the camera body. This address data is read (S 1 ), and the read data is determined (32). When it is determined whether the memory card 8 has a built-in booster circuit, the power supply circuit 11 on the camera body side
Since the power supply to the memory card 8 from the camera body is unnecessary, turn off the power supply (33).If the booster circuit is not built-in, writing and erasing cannot be performed unless high voltage is supplied from the camera body side. Turn on the power supply to the memory card 8 from the side power supply circuit ■1
(S4).

In addition, data indicating the presence or absence of a booster circuit is not stored in the EEPROM, and writing and erasing using a 5V voltage supply is attempted, assuming that the memory card 8 which normally has a built-in booster circuit is used. When it is determined that writing and erasing can be performed by the reading operation, it is determined that the memory card 8 has a built-in booster circuit and that writing and erasing can be performed.
If erasure cannot be performed, it means that the booster circuit is not built-in.

That is, as shown in FIG. 5, when the memory card 8 is inserted into the camera body, first, predetermined data is written to an address for detecting the booster circuit, where there is no problem even if the stored contents are destroyed. , the operation of erasing the data stored at the address is performed using the normal 5V supply (
S11).

Then, the contents of the address are read (S12
), and determines whether writing has actually been performed or erasing (313). When writing or erasing is successful, it is determined that the memory card 8 has a built-in booster circuit (S14), and high voltage is not supplied from the camera body (315). On the other hand, if writing/erasing could not be performed, it is determined that the booster circuit is not built into the memory card 8 (S16), and a high voltage for writing/erasing is applied to the memory card 8 from the power supply circuit 11 on the camera body side. supply (SL?).

Here, reading from the memory card 8 is performed. A control block 9 that performs writing and erasing operations constitutes a booster circuit detection means.

By using the various booster circuit detection means as described above, the EEPR
When the presence or absence of a booster circuit in the memory card 8 with a built-in OM is detected, the control block 9, which constitutes a high voltage supply means together with the power supply circuit 11, turns off the power supply for the memory card 8 without a built-in booster circuit. The high voltage from the circuit 11 is supplied to the memory card 8, and the power supply circuit 11
Writing and erasing is performed using a high voltage from
Aims to reduce current consumption without supplying high voltage from the

If a high voltage is supplied from the power supply circuit 11 to the memory card 8 which does not have a built-in boost circuit, there is no delay time for generating a high voltage in the boost circuit in the memory card 8, so writing and erasing can be performed easily. operation can be made faster.

Further, the power supply circuit 11 is not provided exclusively for writing/erasing the memory card 8, but is provided for the image sensor 3.
There is no need to provide a separate power supply circuit for the memory card 8 on the camera side. <Effects of the Invention> As explained above, according to the present invention, the presence or absence of a booster circuit in an external memory consisting of a PROM that is written and erased by applying a high voltage is detected, and the camera is activated only when a booster circuit is not built-in. Since high voltage is supplied from the main unit, external memory without a built-in booster circuit can speed up writing and erasing operations by supplying high voltage from the camera side, while external memory with a built-in booster circuit can When this is used, unnecessary high voltage supply from the camera body side can be avoided and current consumption can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a block diagram showing the configuration of a still video camera according to an embodiment of the present invention, and FIG. 3 is a memory constituting the booster circuit detection means in the same embodiment. Perspective view showing the external shape of the card, No. 4
5 and 5 are flowcharts showing other embodiments of the booster circuit detection means, respectively. 1...Optical system 3...Image sensor 5...A/
D converter 8... Memory card 8a... Recessed portion 9... Control block 11... Power supply circuit 1
2...Switch

Claims (1)

[Scope of Claims] A digital image signal obtained by converting an optical image signal of a subject obtained by an optical lens into an electrical image signal by an image sensor, and further converting this electrical image signal by an analog-to-digital converter, In a still video camera configured to store and record images in an external memory that is configured to be composed of a PROM that is written and erased by applying a high voltage and that is configured to be freely attachable and detachable to the camera body, the high voltage that is used for writing and erasing the PROM is provided. A step-up circuit detection means for causing the camera body to detect whether the step-up circuit is built into the external memory or not; A still video camera comprising: high voltage supply means for supplying high voltage for writing and erasing from the camera body side to the external memory.