JPS6259461A - Bipolar type image sensor intergrated circuit - Google Patents

Abstract

PURPOSE:To delete drastically circuit elements by forming an image sensor drive circuit on the same chip as an image sensor, and by outputting a serial/ parallel conversion control signal for converting the data into the parallel data. CONSTITUTION:When a reading start pulse is inputted to a terminal 21, respective FF in a shift register is cleared and a signal informing the reading start is outputted to an image sensor drive circuit 6 from a terminal 25. When a clock pulse is inputted to a terminal 22, current switches are selected in a sequence of Q1, Q2... and phototransistors TR are successively driven. Every time when a serial output synchronous with the clock pulse is outputted from an output terminal 23 and eight serial outputs, for instance, are outputted, a latch pulse is outputted from a terminal 24. Herein, when the last phototransistor TR is driven, and then, a signal is outputted to the circuit 6 from a terminal 26 to complete the reading. Thereby, it is not necessary to dispose a serial/ parallel covnersion circuit externally.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a bipolar image sensor integrated circuit within an image reading device.

Background Art Image sensors are used in image reading devices such as facsimiles. FIG. 4 shows an example of a conventional reading section. 1 is an image sensor, 2 is an image sensor drive circuit, and 3 is an image sensor output “0” or “1”.
Binarization circuit 4 converts the binary bit-serial data into bit-parallel data with a predetermined number of bits (e.g. 8 bits) for processing by a microcomputer, etc. 5 is an image data processing circuit. The operation will be explained below.

When a reading start signal is input to the image sensor drive circuit 2, the image sensor 1 is driven, and the image signal is output as serial data and converted into a binary signal of "0゛ or"1 degree by the binarization circuit. After that, a predetermined number of bits (e.g. 8 bits) is converted by a serial/parallel conversion circuit.
The data is converted into bit-parallel data and sent to the image data processing circuit.

Problems to be Solved by the Invention However, with the above configuration, a special serial/parallel conversion circuit is required before sending the read data to the image data processing circuit, and the circuitry around the image sensor becomes large. It had the problem of being stored away.

In view of the above problems, the present invention provides a bipolar image sensor integrated circuit that facilitates the construction of peripheral circuits.

Means for Solving the Problems In order to solve the above problems, the bipolar image sensor integrated circuit of the present invention forms an image sensor driving circuit on the same chip as the image sensor by a bipolar process, and generates a reading start pulse. An input terminal, a clock input terminal, a terminal for outputting bit serial data from the image sensor element, and a serial/parallel conversion for converting the data into bit parallel data of a predetermined number of bits. It is equipped with a terminal that outputs a control signal.

Effect: With the above configuration, the image sensor and its peripheral circuits are integrated into one integrated circuit, thereby achieving miniaturization of the circuit.

Embodiment FIG. 1 is a block diagram showing an embodiment of the present invention, in which 6 is an image sensor driving circuit, 7 is an image sensor array, and 8 is a block diagram showing an embodiment of the present invention.
9 is a shift register for sequentially driving the sensor array in time series, and 9 is an OR gate for outputting a pulse every time eight pieces of serial data are output. Figure 2 shows a circuit diagram of the image sensor array and shift register in Figure 1, where 10 is a phototransistor array, 11 is a current switch array for driving the phototransistor, and 12 is a shift register. 21 is a read start pulse input terminal, 22 is a clock pulse input terminal, 23 is a serial data output terminal, 24 is a latch pulse output terminal, 25 is an output terminal for notifying the start of reading, 26 are output terminals that notify the end of reading, Ql, C2,...
is each switch in the current switch array. Figure 3 shows the timing of each signal in Figure 2.
al is the reading start pulse, (b) is the clock pulse, (c) is the serial output, and (dl is the launch pulse).

The operation of the bipolar image sensor integrated circuit configured as described above will be explained with reference to FIGS. 1, 2, and 3.

When the reading start pulse (a) shown in FIG. 3 is input to the terminal 21, each flip-flop in the shift register is cleared and a signal indicating the start of reading is outputted from the terminal 25 to the image sensor drive circuit 6. When the clock pulse (bl shown in FIG. 3) is input to the terminal 22, the current switches are selected in the order of Ql-Qz, .
The phototransistors are sequentially driven, and a serial output (C) synchronized with the clock pulse (b) is output from the terminal 23, and the serial output (latch pulse fd every 8 times C1 is output) is output from the terminal 23. It is output from 24. When the last phototransistor is activated, terminal 26
A signal is output from the image sensor drive circuit 6 to the image sensor drive circuit 6, and reading is completed.

Effects of the Invention As described above, the present invention obtains a serial/parallel conversion control signal by adding a small number of elements to the shift register for driving the image sensor array in time series. It is not a burden. In addition, there is no need to provide an external serial/parallel conversion circuit, and the number of circuit elements can be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a bipolar image sensor integrated circuit showing an embodiment of the present invention, FIG. 2 is a circuit diagram of an image sensor array and a shift register of the same circuit, and FIG.
This figure is a timing diagram of each signal in FIG. 2, and FIG. 4 is a block diagram of a conventional circuit. 6... Image sensor drive circuit, 7...
- Image sensor array, 8 - Old shift register, 9 - OR gate, 10 - Phototransistor array, 11 - Current switch array, 12 - ·····flip flop. Name of agent: Patent attorney Toshio Nakao (Figure 1)

Claims (1)

[Claims] A sensor array consisting of a plurality of image sensor elements, a shift register that sequentially drives the image sensor elements in time series, a terminal for inputting a reading start pulse, a terminal for inputting a clock, and a terminal for inputting a clock from the image sensor elements. A bipolar type characterized in that it has a terminal that outputs bit-serial data of a predetermined number of bits, and a terminal that outputs a serial/parallel conversion control signal for converting the data into bit-parallel data of a predetermined number of bits. Image sensor integrated circuit.