JPS62185474A - Semiconductor device - Google Patents

Abstract

PURPOSE:To reduce the number of wirings and to easily equip the titled device camera by reading signals under the same condition according to respective semiconductor devices in a range finding of an automatic focussing type using the two semiconductor devices and outputting the difference of the read signals by a differentials amplifier. CONSTITUTION:The image of an object 12 passing through two parts of a photographing lens 11 passes through a finder screen 13, thereafter is projected on the respective semiconductor devices through a focal point detecting lens 9. In the two semiconductor devices 10, the signal output terminal 4 of the first device is connected to the signal input terminal 6 of the second device. A driving signal and a power supply input for driving the respective semiconductors are supplied through one device, for instance the second device. When the range finding is executed by the two connected and synchronously driving semiconductors in this way, if the focusing is not performed, the two images are dislocated outside or inside according to the position of the lens. Consequently, the output signals of the two semiconductor devices are also changed by this dislocation. Therefore, the output signals of the respective semiconductor devices are inputted to the differential amplifier to obtain a difference signal. From this difference signal, the lens driving signal for obtaining the focusing is obtained.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a semiconductor device, and more specifically, a semiconductor device that is effective for an autofocus method in which distance measurement is performed by placing two light-receiving elements at positions apart from each other. Regarding equipment.

[Prior art]

Conventionally, autofocus methods for cameras, etc., have been used, for example, to measure distance by receiving light emitted from a camera's built-in light source (LED, strobe) from the subject, or by measuring the distance based on the clarity of the received subject image. Methods for measuring distance are known.

However, the former usually splits the viewfinder image.
This is a so-called single-point distance measurement that focuses on the image, and has the drawback that it is too large and expensive to perform multi-point distance measurement that measures a wide range f of the screen.

On the other hand, the latter method 1 has the disadvantage of requiring mechanical operations such as moving the lens or moving the light receiving element in order to obtain focus.

As an alternative to these methods, the light passing through two parts of the photographic lens is detected by two light receiving elements,
There is a method of determining the image position from changes in the output signals of each element. In this case, in order to obtain high distance measurement accuracy, it is necessary to use an image sensor that can obtain high resolution by arranging photodiodes at intervals of about 20 μm, for example.

[Problem that the invention seeks to solve]

However, such image sensors have not been put into practical use because they are too expensive and because the two elements must be driven synchronously, making the drive circuit complicated and difficult to use. Ta.

The object of the present invention is to solve the above-mentioned circumstances by:
It is an object of the present invention to provide a semiconductor device t that can be effectively used when measuring distance by placing two light receiving elements at positions separated from each other.

[Means and operations for solving the problem] According to the present invention, this object is achieved as follows. That is, in a semiconductor device that sequentially reads out signals from a plurality of photosensors arranged in a matrix using clock signals from a vertical shift register and a horizontal shift register, a synchronization signal generator that adds a synchronization signal to the clock signal; It is equipped with a differential amplifier installed on the output side of the sensor.
The differential amplifier is connected so that the output of the photosensor and an external signal via the signal input terminal can be input, and supplies the output to the output terminal, and the output of the photosensor is branched from the input side of the differential amplifier to output the signal. This is achieved by a semiconductor device characterized in that it is connected to a terminal.

By scanning the photosensor with a clock signal to which a synchronization signal is added in this manner, in a distance measuring method using two of these semiconductor devices, each semiconductor device reads out signals under the same conditions.

Furthermore, the differential amplifier allows each device to output the difference between the signals read.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic block diagram of a semiconductor device constructed according to the present invention. In FIG. 1, a light receiving section 1 is composed of a plurality of photosensors arranged in a square pattern, and a signal is obtained by exposing the light receiving section 1 to light. The obtained signal is transferred to vertical shift register 2.
and a drive signal from the horizontal shift register 3 and read out to the signal output terminal 4. In addition, the signal from the light receiving section 1 is branched and supplied to one input terminal of the differential amplifier 50 provided on the same board, and the other input terminal (-) of the differential amplifier 5 is supplied to the signal input terminal. 6 is connected so that an external signal can be inputted.
The output of is connected to output terminal 7.

Further, drive signals and power inputs (Vcc, V
ss ) is supplied via a synchronization signal generator 8 also provided on the board. This synchronization signal generator 8 adds a synchronization signal to the input clock input and supplies it to the shift register.

FIG. 2 illustrates a method of using the semiconductor device of the present invention.

In the camera finder section, two sets each of a focus detection lens 9 and a semiconductor device 1o of the present invention are provided.

The image of the subject 12 that has passed through the two parts of the photographic lens 11 passes through the finder screen 13 and is then projected onto each semiconductor device 10 via the focus detection lens 9. In the two semiconductor devices 10, the signal output terminal 4 of the first device is connected to the signal input terminal 6 of the second device. Further, drive signals and power input for driving each semiconductor device are supplied through one device, for example, a second device.

When distance measurement is performed using two semiconductor devices connected in this way and driven synchronously, when the focus is on, two
The same image appears at the center of each of the two semiconductor devices, and when the two images are out of focus, the two images shift outward or inward depending on the lens position. Therefore, the output signals of the two semiconductor devices also change due to this deviation.By inputting the output signals of each semiconductor device to the differential amplifier 5 to obtain a difference signal, it is possible to obtain focusing from this difference signal. When the lens drive signal is obtained, that is, when the focus is in focus, the voltage level of the difference signal is almost zero (in reality, it is the minimum value due to variations in the circuit elements), and when the focus is not in focus, the difference signal is output and the voltage level is almost zero. Front pin and rear pin information can be obtained from the positive and negative values.

Note 8. Although FIG. 2 1 is obviously not correct, the above description may be the reason why the differential amplifier 5 of the first semiconductor device Wt (in the case of this practical example) 10 is not necessary, so a combination with and without a differential amplifier is used. Other uses will also be considered.

FIG. 3 illustrates another embodiment of the invention in which the power input is provided to form a clock input. That is, a rectifying section 14 is provided on the input side of the synchronizing signal generator 8, and a clock input is supplied to the rectifying section 14 and the synchronizing signal generator 8, respectively. The rectifier 14 is connected to the ground side of the power input, and the clock input is connected to the rectifier 1.
4 to obtain DC power. The rest of the configuration is the same as that in FIG. 1 above. As is clear from the figure, this semiconductor device is driven only by the supply of a clock input, reducing the number of wiring lines.

C. Effects of the Invention] As described above, according to the semiconductor device of the present invention, when two light receiving elements are used in an autofocus system, the number of light receiving elements can be extremely reduced, and usage performance can be improved. Additionally, since the operational amplifier is also provided on the same board, it is advantageous to mount it on the camera.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram according to one embodiment of the present invention;
The figure is a diagram for explaining an example of use of the apparatus shown in FIG. 1, and FIG. 3 is a schematic block diagram showing another embodiment of the present invention. 1... Light receiving part, 2... Vertical shift register, 3...
...Vertical shift register register, 4...Signal output terminal, 5...Differential amplifier, 6...Signal input terminal, 7.
...Output terminal, 8...Synchronization signal generator, 9...
Focus detection lens, 10... Semiconductor device, 14...
- Rectifier section.

Claims (1)

[Claims] In a semiconductor device that sequentially reads out signals from a plurality of photosensors arranged in a matrix using clock signals from a vertical shift register and a horizontal shift register, there is provided a synchronous signal generator that adds a synchronous signal to the clock signal; A differential amplifier is provided on the output side, and the differential amplifier is connected so that the output of the photosensor and an external signal via the signal input terminal can be input, and supplies the output to the output terminal, and the output of the photosensor is 1. A semiconductor device, which is branched from the input side of a differential amplifier and connected to a signal output terminal.