JPH02145069A - Image sensor device - Google Patents

Abstract

PURPOSE:To facilitate the signal processing by storing a signal of remaining photosensing picture element arrays to an analog memory section till one output of photosensing picture element arrays arranged in plural directions is finished for readout sequentially. CONSTITUTION:When the transfer of the signal output of photoelectric picture element arrays a, b is finished, a 2nd transfer control pulse is inputted to a transfer pulse input TG 2 and fed to one input 9 of a 2nd transfer gate, then a signal charge stored tentatively in an analog memory section 5 near a picture element array (c) is transferred to a 2nd shift register 7. In this case, the 2nd transfer pulse is fed to a gate group (e) and the level of a gate signal output terminal beta connecting to a reception buffer 12 of the 2nd shift register 7 goes to H and an output level of other gate signal output terminal gamma goes to L. That is, only one reception buffer 12 among reception buffers 11, 12, 13 is able to be active.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image sensor used as a focus detection device for cameras, videos, etc. Regarding elif. In particular, the present invention relates to an image sensor device used in a split-pupil TTL focus detection device, etc., for converting signal charges from photosensitive pixel arrays having various array structures into time-series signal outputs and transferring the same.

[Prior Art] A focus detection device for a camera or the like uses an image sensor device configured by arranging a plurality of photosensitive pixel rows in multiple directions, and each photosensitive pixel row corresponds to a subject image. The relative movement of each object image on each photosensitive pixel row as the photographic lens moves along the optical axis is determined from the output of this image sensor device, and the focal position of the photographic lens is determined. A focus detection device that detects is known. like this? By arranging photosensitive pixel arrays in multiple directions as described above, the camera was able to detect the in-focus position of the photographic lens regardless of the direction, even when the contrast of the subject changes only in a certain direction. . Such an image sensor is disclosed in Japanese Patent Laid-Open No. 59-60303, and its configuration is shown in FIG. 4.

This conventional example has a JLL dish circuit integrally formed on a semiconductor substrate, using four unit photosensitive pixel columns 14 to 17, and a photosensitive pixel column pair 14 consisting of photosensitive pixels such as photodiodes.
．． 15 and photosensitive pixel column pairs 16 and 17 are arranged so as to be perpendicular to each other, and charge transfer elements such as shift registers and stages 18 to 2 are provided corresponding to each photosensitive pixel column 14 to 17.
1 and 2 are connected in series via delay lines 22 and 23 such as shift registers, respectively, as shown in the figure. Only one output circuit 24 is provided at the output section of the charge transfer means 18. The signal charge groups A to D generated in each of the photosensitive pixel columns 14 to 17 are delayed as necessary for each unit photosensitive pixel column, as shown in FIG. It is output sequentially as a time series signal.

This time-series signal is processed by a microprocessor or the like built into the camera, and is used to detect the focal position of the photographic lens.

[Problems to be Solved by the Invention] However, the above technology has the following problems. The arrangement and size of the photosensitive pixel array are often limited according to the design specifications of the optical system that guides the light image to these L. In this case, the photosensitive pixel array is arranged via a delay line as in FIG. It is not easy to splice the signal outputs from these pixels so that they are aligned in time series.

For example, if the photosensitive pixel arrays 14, 15, 16, and 17 shown in FIG. There may not always be enough space to create a delay, and if you forcefully try to secure the necessary amount of delay, you will have to fold the delay section, which is made up of shift registers, etc., in a complicated manner, resulting in performance deterioration and a decrease in yield. There are other negative effects.

As mentioned above, photosensitive pixel rows A, B, and C.

The method of using a shift register as a delay line in order to take out the charge outputs of D without temporal overlap is largely limited by the arrangement of the photosensitive image arrays, especially when there are multiple arrangement directions. When they are spatially separated, it is difficult to find a good splicing solution. In addition, by using a shift register as a delay line, the structure of the shift register section is complicated, so the area occupied by the shift register section on the chip increases, resulting in a decrease in yield by 1, which increases cost. This has led to disadvantages such as increased bending in the shift register, which degrades performance, and increased drive capacity, which increases power consumption.

[Means for Solving the Problems] In order to solve the above problems, the present invention generates signal charges according to the light intensity of a pair of light images from the same subject, and a first photosensitive pixel column formed by arranging a pair of photosensitive pixel columns including photosensitive pixel elements in the first direction;
a first sequential readout means for transferring signal charges from each of the photosensitive pixel elements as a first signal output group forming a time-series group;
A pair of photosensitive pixel rows are arranged in a second direction different from the first direction to generate a signal corresponding to the light intensity of a pair of light images from the same subject. a second photosensitive pixel column arranged in the array; a memory section for temporarily storing signal charges from each photosensitive pixel of the second photosensitive pixel column; and a time-series group of signal charges temporarily stored in the memory section. a second sequential reading means for transmitting a second signal output group; an output section connected to the first sequential reading means and the 21st@order reading means; and a second sequential reading means for outputting the first signal to the first sequential reading means. The group transfer is started, the signal charges from the second photosensitive pixel column are transferred to the memory section, and after the transfer of the first signal output group is completed, the second sequential readout means receives the signal charges of the second signal output group. An image sensor device is constituted by a control section that starts the transfer and outputs the first signal output group and the second signal output group from the output section without temporally overlapping each other, the image sensor device , 1st
Based on the signal output group and the second signal output group,
A relative shift amount between the pair of optical images is detected in a plurality of directions with respect to the subject.

[Function] In the configuration of the present invention, since the memory means is provided between the second photosensitive pixel column and the second sequential readout means, the conventional delay line is not required, and therefore the entire photosensitive pixel column can be read through the delay line. It is no longer necessary to arrange the photosensitive pixels in a single row, and it has become possible to position the photosensitive pixel rows arbitrarily.

Moreover, in the configuration of the present invention, since a control section is provided for switching the output from each sequential readout means, each signal is outputted from a single output section without temporally overlapping, and the subsequent stage signal processing becomes very easy.

[Embodiment] FIG. 1 shows an embodiment of the present invention, which is an image sensor device formed on a semiconductor substrate. The image of the subject that has passed through the photographic lens is projected as a pair of light images onto each of the first photosensitive pixel arrays a and b by an optical system (not shown), and on the other hand, the image of the subject that has passed through the photographic lens is projected as a pair of light images in the direction orthogonal thereto. An image is formed on each of the two photosensitive pixel columns c and d. Distance measurement or focal point position detection is performed by detecting the amount of relative displacement of the pair of light images on columns a and b or the amount of relative displacement of the pair of light images on columns c and d. However, this method uses the pupil division method T
This is a well-known TL focus detection device and has no direct relation to the present invention, so its details will be omitted.

In the image sensor device of the present invention, as shown in FIG.
, c, d are formed with shift registers of first sequential reading means l and second sequential reading means 7.8.

Each photosensitive pixel element generates a signal charge corresponding to the light intensity of the projected light image.

The shift register of the sequential reading means sequentially outputs the parallel charge signals from each pixel as a time-series signal for each shift register 1, 7, and 8 from an output terminal at one end of each shift register. Reception buffers 11, 12.13 are connected to the output terminals of each shift register 1.7.8, and these reception buffers 11, 12.13 convert time-series charge signals output from the shift registers into time-series voltages. Convert to signal. The reception buffer 11.12.13 has a gate signal input terminal for inputting the output of the gate group e, and selectively receives the output from the gate signal output terminals α, β, and γ according to the H” or “L” digital signals. The output terminals of each receiving buffer 11, 12, 13 are connected to each other to form a single signal output terminal OUT which is an output section.

The memory means, that is, the analog memory section 5.6, provided between the second photosensitive pixel columns c, d and the second shift register 7 and third shift register 8 of the second sequential readout means,
The charge signals from each pixel in each photosensitive pixel column C9d are individually temporarily stored, and after a predetermined period of time, the charge signals from the second pixel in the next stage are stored. It is provided so as to be transferred to the third shift register.

The first transfer gate) 2, 3.4 is a photosensitive pixel row a,
This is provided to control the timing at which the charges stored in each pixel element b, c, and d are transferred to the first shift register l or the analog memory sections 5 and 6. The analog memory section 5.6 and the second. The second transfer gate 9°lO provided between the third shift register 7.8 is
The charges stored in each memory element of the analog memory section are transferred to the second. Transfer is controlled to the third shift register 7.8.

The gate group e, which forms the main part of the control section, is NOR as shown in the figure.
and an AND circuit, the first
It is connected to an external circuit together with the transfer gate or the second transfer gate, and generates a control signal for canceling or inhibiting the output of the receiving buffers 11, 12, and 13 in synchronization with an external control signal of the transfer gate.

The operation of the image sensor device configured as described above will be explained below.

FIG. 2 is a timing chart showing the operation of the above device. When an external digital control signal is input to the input terminal Int as an accumulation control signal and applied to the pixel columns a, b, c, and d, the charges generated in the photosensitive areas of the pixel columns a, b, c, and d are This control signal starts to accumulate (time 1.) and is applied until a predetermined time when the signal output from the image sensor device reaches an appropriate level. When the first transfer control pulse is input to the transfer pulse input TGI (time tz) and applied to the first transfer gates 2 and 3.4, the charge signals accumulated in the pixel columns a and b are transferred to the first shift register l. The charge signals transferred and accumulated in the pixel columns C and d are stored in the analog memory section 5.6.
will be transferred to. At this time, the first transfer pulse is also applied to the gate group e, and only the gate signal output terminal α connected to the receiving buffer 11 of the first shift register l has an output of "H", and the output of the other gate signal output terminals β, γ The output remains at "L"'. In other words, only one of the receive buffers 11, 12, and 13 becomes operational.

The first photosensitive pixel row a is taken into the first shift register 1 after inputting the first transfer control pulse.

The charge signal from each pixel element b is sequentially transferred by the transfer lock signal input to the clock terminal φC, and is sequentially converted into a voltage signal by the receiving buffer 11 (shown as the output of the receiving buffer 11 in FIG. 2). ), the signals are output in time series from the signal output terminal OUT of the output section as a first signal output group corresponding to a group of received light intensity distributions.

When the transfer of the signal outputs of the photosensitive pixel rows a and b is completed, the second
A transfer control pulse is input to transfer pulse input TG2 (t
3) When applied to one side 9 of the second transfer gate, the signal charge temporarily held in the analog memory section 5 near the pixel column C is transferred to the second shift register 7.

At this time, the second transfer pulse is also applied to the gate group e, and the second
Only the gate signal output terminal β connected to the reception buffer 12 of the shift register 7 outputs "H", and the output of the other gate signal output signal terminals γ becomes "L". In other words, only one reception buffer 12 among the reception buffers 11, 12, and 13 becomes operational.

After the second transfer control pulse is applied, the charge signals from each pixel of the photosensitive pixel column C taken into the second shift register are as follows:
The signals are sequentially transferred by the transfer lock signal input to the clock terminal φC, and sequentially converted into voltage signals by the receiving buffer 12 (shown as the output of the receiving buffer 12 in FIG. 2).
, are output in time series from the signal output terminal OUT as the first half of the second signal output group corresponding to the intensity distribution of the light received by the photosensitive pixel 1C.

When the transfer of the signal output of the photosensitive pixel column C is completed, the third transfer control pulse is input to the transfer pulse input TG3 (tl,
When applied to the other lO of the second transfer gate, the signal charge temporarily held in the analog memory section 8 near the pixel column d is transferred to the third shift register 8. At this time, the third transfer pulse is also applied to the gate group e, and only the gate signal output terminal α connected to the reception buffer l3 of the third shift register 8 becomes "H", and the output of the other gate signal output signal terminals α, The output of β becomes "L" 9. In other words, only one of the reception buffers 11, 12.13 becomes operational.

After inputting the third transfer control pulse, the charge signals from each pixel of the photosensitive pixel column d taken into the third shift register are as follows:
The signals are sequentially transferred by the transfer lock signal input to the clock terminal φC, and sequentially converted into voltage signals by the receiving buffer 13 (shown as the output of the receiving buffer 13 in FIG. 2).
, are output in time series from the signal output terminal OUT as the latter half of the second signal output group corresponding to the received light intensity distribution of the photosensitive pixel row d.

As described above, the first step. Second photosensitive pixel rows a, b, c,
The signal charges accumulated in each photosensitive pixel of d are output from the signal output terminal OUT as a time-series signal without duplication. (See the output of OUT in FIG. 2) In the embodiment of the present invention, not only the above operation but also the operation shown in the first order is possible. Repeat this action in the 3rd U.
This is shown in timing chart A.

The embodiment of the present invention includes photosensitive pixel arrays a in multiple directions.

It is configured to output a group of signal outputs corresponding to the received light intensities of b, c, and d as time-series signal outputs from a single output terminal OUT. Therefore, for example, when higher-speed processing is required,
Processing only the signal output from the first photosensitive pixel arrays a and b
If it is desired to omit the processing of the signal output from the first photosensitive pixel arrays a and b, the signal output from the first photosensitive pixel arrays a and b may be swept out at high speed.

That is, as shown in FIG. 3, the first photosensitive pixel rows a, b
When transferring the signal output from the first shift register, the period of the transfer lock signal is shortened as φC, and the signal charge transferred to the first shift register is swept out at high speed. 1st above
After the signal outputs from the photosensitive pixel rows a and b are swept out at high speed, the period of the lock signal is transferred again as long as g of the input of φC, and the transfer control pulse is transferred to the input of TGI, TG2.
The inputs of TG3 and TG3 are applied, and the charge signals from the second photosensitive pixel rows c and d are outputted as shown in the output of OUT.

Note that the period of the transfer lock signal g is 1, for example, the period of the transfer lock signal g is 1.
It is set to an appropriate length depending on the processing constant of the D conversion circuit.

Conversely, if only the signal outputs from the first photosensitive pixel columns a and b are processed and the processing of the signal outputs from the second photosensitive pixel columns c and d is omitted, the second photosensitive pixel column c, By shortening only the period of the transfer lock signal g of d, it becomes possible to sweep out the signal charges transferred to the second and third shift registers at high speed.

In the embodiments of the present invention, the photosensitive pixel columns are shown as two pairs of orthogonal pixel columns, but many other modifications, such as increasing the number of photosensitive pixel columns or changing the angular direction of the photosensitive pixel columns with respect to each other, are contemplated by the present invention. within range.

[Effects of the Invention] As described above, according to the present invention, until the output of one of the photosensitive pixel columns arranged in a plurality of directions is sequentially read out, the signals of the remaining photosensitive pixel columns are held in the analog memory section. ,
After the output of one photosensitive pixel column signal is completed, the signals from each of the remaining photosensitive pixel columns are read out sequentially, and the signals from the plurality of photosensitive pixel columns arranged in multiple directions are converted into a single time-series signal. Since it can be taken out from one output terminal, signal processing has become extremely easy.

Furthermore, compared to the case where a shift register or the like is used as a delay line, there is no reduction in transfer efficiency due to an increase in the overall length of the shift register, there is no decrease in yield due to an increase in the area occupied on the chip, and there is no problem with bending of the shift register. Since there is no deterioration in performance that would occur if there are a large number of parts, there is an effect that a high-performance, low-cost image sensor device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an image sensor device according to an embodiment of the present invention, FIG. 2 is a timing chart showing an example of the operation of the image sensor device according to the present invention, and FIG. FIG. 4(a) is a timing chart showing another example of the operation of the image sensor device of the present invention, and FIG. 4(a) has a structure in which photosensitive pixel columns formed in four directions are connected by a shift register. FIG. 4(b) is a schematic diagram of an image sensor device, and FIG. 4(b) is a diagram showing that the image sensor device of FIG. 4(a) outputs signals without overlap. (Explanation of symbols of main parts) a, b・・・・・・・・・・・・・・・・・・First photosensitive pixel row c, d・・・・・・・・・・・・・・・・・・・・・・・・・・・
・Second photosensitive pixel row e”・・・・・・・・・・・・・・・
・・・・・・Gate group l・・・・・・・・・・・・・・・
......First shift register 7...
・・・・・・・・・・・・・・・・・・・・・Second shift register 8・・・・・・・・・・・・・・・・・・・・・
・・・・Third shift register 1 Figure 6・・・・・・・・・・・・・・・Analog memory section 3.4・・・・・・・・・EfSl) -Transfergate lO・・・・・・・・・・・・Second
Transfer gate, 12.13...Receive buffer Figure 2, Figure 3

Claims (1)

[Scope of Claims] A signal charge corresponding to the light intensity of a pair of identical light images is generated, and a pair of photosensitive pixel rows consisting of a plurality of photosensitive pixel elements arranged in a first direction are arranged in the first direction. a first photosensitive pixel array; a first sequential reading means for transferring signal charges from each of the photosensitive pixel elements as a first signal output group forming a time-series group; a second photosensitive pixel column formed by arranging a pair of photosensitive pixel columns in the second direction, each consisting of a plurality of photosensitive pixel elements arranged in a second direction different from the first direction; a memory section that temporarily stores signal charges from each photosensitive pixel element in the two photosensitive pixel columns; and a second sequential readout that transfers the signal charges temporarily stored in the memory section as a second signal output group forming a time-series group. means, an output section connected to the first sequential readout means and the second sequential readout means, for causing the first sequential readout means to start transferring the first signal output group from the second photosensitive pixel column; After transferring the signal charges to the memory section and completing the transfer of the first signal output group, the second sequential reading means starts transferring the second signal output group, and the first signal output group and the first signal output group are transferred. a control unit that outputs two signal output groups from the output unit without temporally overlapping each other, and a control unit that outputs two signal output groups from the output unit without temporally overlapping each other, and controls the relative output of the pair of identical optical images based on the first signal output group and second signal output group An image sensor device that detects the amount of misalignment.