JPS62122284A - Semiconductor light receiving element - Google Patents

Abstract

PURPOSE:To perform stable, accurate position detection, in a light receiving element having a light receiving part, in which cells are arranged in a matrix pattern, by changing the ratio of the numbers of light receiving cells, which are connected to first and second wirings for every region corresponding to the diameter of incident light, at a specified rate toward the direction of the position detection. CONSTITUTION:Light receiving cells 11 are arranged in a matrix pattern in a light receiving part. Ten groups of regions 14 corresponding to the diameter of incident light from the left end to the right end are provided in the light receiving part. Ten light receiving cells are arranged in each group. The ratio of the light receiving cells 11, which are connected to a first wiring 12 and a second wiring 13 is changed from 9:1-1:9 at a constant rate. When the light is inputted to the region 14 corresponding to the diameter of the incident light at, e.g., the second column from the left, the ratio between photovoltaic currents I11 and I12, which are sent to the first wiring 12 and the second wiring 13, becomes 4:1. When the light is inputted to the region 14 corresponding to the diameter of the incident light in the third column from the right, the ratio between the photovoltaic currents I11 and I12, which are sent to the first and second wirings 12 and 13, becomes 3:10. Thus, in this semiconductor light receiving element, the photovoltaic currents I11 and I12 with the ratio corresponding to the position of the incident light can be sent to the first and second wirings 12 and 13 without resistors, and faulty operation does not occur due to the intensity of the incident light.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor light receiving element that detects the position of incident light.

[Conventional technology]

FIG. 3 is a schematic diagram showing a PSD which is an example of a conventional semiconductor light-receiving element, where 1 is the PSD light-receiving surface and 2 is an incident light spot. 4 is an equivalent circuit diagram of the PSD shown in FIG. 3, where 3 is a silicon photodiode, 4 is a resistor, and T1 and T2 are output terminals.

FIG. 5 is a configuration diagram showing an amplification circuit for amplifying the output of the PSD, where 5 is the SPD, 6a and 6b are operational amplifiers, and 7a
, 7b are resistors.

Next, the operation will be explained.

When the incident light spot 2 hits the PSD light receiving surface 1, a photovoltaic current is generated by the internal silicon photodiode 3,
A current I flows through a predetermined number of resistors 4 determined by the position of the incident light spot 2 from the terminals T, , T, respectively.
, I2 is output.

Thereafter, the currents I, , I2 are amplified by the amplifier circuit shown in FIG. 5 and output.

[Problem that the invention seeks to solve]

In the conventional semiconductor device as described above, a high voltage is generated between the terminals T1 and T2 and the light receiving part by the resistor 4, and when the intensity of the incident light is particularly strong, the silicon photovoltaic device 1 and the diode 3
In this case, a forward current flows through the silicon photodiode 3, making it impossible for the silicon photodiode 3 to detect incident light. On the other hand, in the amplifier circuit shown in FIG. 5, for example, when the output of one operational amplifier 6b fluctuates,
There is a problem in that the output flows to the input of the operational amplifier 6a via the resistor 7b and the resistor 4 in the PSD 5, causing an error in the output of the amplifier circuit.

This invention was made in order to solve such problems, and the object is to obtain a semiconductor light receiving element that can accurately detect a position without causing malfunction even when the intensity of incident light is strong. shall be.

[Means for solving problems]

The semiconductor light-receiving element according to the present invention has light-receiving parts arranged in a matrix, and the ratio of the distribution of the light-receiving parts connected to the first and second wirings is determined for each area corresponding to the diameter of incident light. It is changed at a predetermined rate in the direction of detection.

[Effect]

In this invention, the ratio of the photovoltaic current sent to the first and second wirings due to the incident light incident on the light receiving section for each region corresponding to the diameter of the incident light changes in the direction of position detection. .

〔Example〕

FIG. 1 is a schematic diagram showing an embodiment of a semiconductor light-receiving element of the present invention, in which 11 is a light-receiving cell which is a light-receiving section made of, for example, a first silicon diode, 12 is a first wiring, and 13 is a second wiring. , 14 indicate the area with respect to the diameter of the incident light.

Here, for simplicity, it is assumed that incident light enters a slit having the same diameter as the area 14 corresponding to the diameter of the incident light, and there are 10 groups of areas 14 corresponding to the diameter of the incident light from the left end to the right end, and each of them A first wiring 12 and a second wiring 13 for each group.
The ratio of the light receiving cells 11 connected to the 9:1 to 1:9
We will explain the case where the value is changed at a constant rate.

Next, we will discuss the operation.

When the incident light enters the area 14 corresponding to the diameter of the incident light in the second row from the left, the first wiring 12 and the second wiring 13
The ratio of the photovoltaic current ■11y112 sent to The ratio of the photovoltaic currents 111°112 sent out is 3:10. Therefore, in this semiconductor photodetector, a photovoltaic current I 11 of a ratio corresponding to the incident position of the incident light can be generated without using a resistor.
+I 12 can be sent to the first wiring 12 and the second wiring 13, respectively, and malfunctions will not occur due to the intensity of the incident light.

Furthermore, when this semiconductor photodetector is connected to an amplifier circuit, a second
It will look like the figure. In FIG. 2, the same reference numerals as in FIG. 5 indicate the same parts, and numeral 8 designates the semiconductor light receiving element of the present invention shown in FIG.

As is clear from FIG. 2, the operational amplifier 5a.

6b are connected only through a plurality of silicon photodiodes constituting a light receiving cell 11 in the semiconductor light receiving element 8. Therefore, even if the output of either operational amplifier 6a or 6b fluctuates, the output flows to the input of operational amplifier PJ6b or 6a on the opposite side, and no error occurs in the output of the amplifier circuit.

Note that when the incident light in the form of a slit having the same diameter as the area 14 corresponding to the diameter of the incident light enters, the first wiring 12 and the second wiring 13 are disposed on the entire light receiving surface.
The distribution of the light-receiving sections 11 may not be uniform even if the light-receiving section 11 is connected to the

Further, in the above embodiment, the case where a slit-shaped incident light is incident has been explained, but when a spot-shaped incident light is incident, the light receiving section should be made sufficiently small with respect to the spot diameter.4. In addition, the ratio of the distribution of the large number of light receiving parts connected to the first wiring and the second wiring on the entire surface of the light receiving surface is changed at a predetermined ratio in the direction of position detection, that is, the distribution of the two systems. By using a stochastic distribution, position detection can be performed with high accuracy.

Furthermore, three-dimensional position detection can be performed by providing a third wiring and connecting the light receiving section 11.

〔Effect of the invention〕

As explained above, this invention has light receiving sections arranged in a matrix, and detects the position by detecting the ratio of the distribution of the light receiving sections connected to the first and second wirings for each area corresponding to the diameter of the incident light. Since the change is made at a predetermined rate in the direction of the incident light, the incident light that enters the light receiving part per area corresponding to the diameter of the incident light is sent to the first and second wiring of the photovoltaic current. The effect is that the ratio changes in the direction in which position detection is performed, and position detection can be performed accurately with stable operation.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the semiconductor photodetector of the present invention, FIG. 2 is a schematic diagram showing the case where the semiconductor photodetector of the present invention is connected to an amplifier circuit, and FIG. 3 is a schematic diagram of a conventional semiconductor photodetector. 4 is an equivalent circuit diagram of the PSD shown in FIG. 3, and FIG. 5 is a configuration diagram showing an amplification circuit for amplifying the output of the PSD. In the figure, 11 is a light receiving cell, 12 is a first wiring, and 13 is a light receiving cell.
is the second wiring, and 14 is a region corresponding to the diameter of the incident light. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Masuo Oiwa (2 others) Figure 1 Figure 2 Figure 7, :I Figure 4 Figure 5 Figure 7

Claims (1)

[Claims] A semiconductor light-receiving element that detects the position of incident light using a photovoltaic current generated by the incident light that enters the light-receiving part has light-receiving parts arranged in a matrix, and a first and a first one for each area corresponding to the diameter of the incident light. 2. A semiconductor light-receiving element, characterized in that the distribution ratio of the light-receiving parts connected to the second wiring is changed at a predetermined rate in the direction of position detection.