CN103453877B - Self-powered monolithic integration digital sensor for detection of light source direction - Google Patents

Abstract

The invention discloses a self-powered single-chip integrated digital sensor for light source direction detection, which includes a light sensing unit module and a light direction angle detection module; the light sensing unit module includes arrays arranged on a P-type substrate Photoelectric induction unit; each photoelectric induction unit includes a shielding wall and photodiodes symmetrically arranged on both sides thereof; the photodiode is a PN junction composed of an N well on a P-type substrate and a P+ doped layer of the N well Photodiode; the light direction angle detection module includes a Flash ADC circuit with a current mirror structure, and the Flash ADC circuit includes a left current mirror and a right current mirror that output digital signals. The optical sensing unit module of the present invention can supply power to the Flash ADC circuit, thereby realizing the self-power supply of the digital sensor; moreover, it is very easy to design and produce, the unit cost is very low after mass production, the volume and weight are small, and the reliability is high.

Description

A self-powered monolithic integrated digital sensor for light source direction detection

technical field

The invention belongs to the technical field of optical sensors, and relates to a self-powered single-chip integrated digital sensor for detecting the direction of a light source.

Background technique

The relative direction and motion state detection between the light source and the detection device play an important role in many aspects. Many spacecraft such as satellites need to detect the relative direction to the sun in order to determine the attitude of the satellite, and accordingly adjust the angle of the solar panels to align with the sun for efficient power generation. In solar power plants, solar lighting, solar cars and other applications that use solar energy for photovoltaic power generation, there is the same need, which is of great significance for improving power generation efficiency. According to the change law of the light source (or shadow), the motion characteristics such as the speed and direction of the light source (or sensor) can be obtained, and its application field is more extensive.

At present, there are many methods for detecting the direction of incident light, but they are all based on the larger board box slot structure and other shadow structures, such as baffles, mirrors and apertures, etc., and these methods are designed to allow light coming from different directions to illuminate Different light sensors require a relatively long distance between the light window and the light sensing device, which requires the use of special mechanical and optical devices, which have the disadvantages of large size, difficult fabrication, and low reliability. At present, there is no incident light direction detection device realized by using the micro-scale structure of an integrated circuit.

In many occasions such as aerospace, wild and uninhabited areas, implanted medical electronics, safety testing, etc., due to the limited power supply or even difficulty in obtaining it, it is always hoped that a circuit with as low power consumption as possible can be designed to prolong the life of the device. The ultra-low power consumption design of circuits is considered to be an important direction for the development of integrated circuits in the next ten years. At present, the most attractive technology is energy harvesting (Energy Harvesting), whose basic idea is to obtain energy in the application environment of electronic equipment, and convert it into electric energy supply circuit through energy converter. Energy harvesting and self-powered designs are relatively new areas of research that have seen an increase in research in recent years. Research on energy harvesting includes many aspects (mechanical energy, thermal energy, light energy), but most of them only focus on energy harvesting, and have not considered it in combination with signal processing, especially the research on energy harvesting realized on integrated circuits has not been seen. In fact, many circuit functions can be realized by combining ultra-low power consumption circuit design and low voltage blocking method. Most of the research on self-power is still based on system-level research, that is, systems that include energy harvesting (such as solar panels), signal processing circuits, actuators, etc. So far, no research has been seen on a fully self-powered implementation on a single chip.

Contents of the invention

The problem solved by the present invention is to provide a self-powered single-chip integrated digital sensor for light source direction detection, which realizes the output digital signal to detect the incident angle of the light source, and has the characteristics of self-power supply, small volume and high integration.

The present invention is achieved through the following technical solutions:

A self-powered single-chip integrated digital sensor for light source direction detection, including a light sensing unit module and a light direction angle detection module;

The photo-sensing unit module includes photo-sensing units arranged in an array on a P-type substrate; each photo-sensing unit includes a blocking wall and photodiodes symmetrically arranged on both sides thereof; the photodiodes are integrated It is made of the PN structure formed when the P-type material in the circuit process is in contact with the N-type material;

Described light direction angle detection module comprises the Flash ADC circuit of current mirror structure, and this FlashADC circuit comprises the left side current mirror of output digital signal and the right side current mirror;

The left current mirror includes a left reference NMOS transistor and a left comparison NMOS transistor, the drain of the left reference NMOS transistor is connected to the reference photodiode D _Rref on the right side of the shielding wall, and the drain of the left comparison NMOS transistor is connected to the left reference NMOS transistor. The quantized area photodiodes on the left side of the shielding wall are connected, the gates are interconnected, and the source is grounded;

The right current mirror includes a right reference NMOS transistor and a right comparison NMOS transistor, the drain of the right reference NMOS transistor is connected to the reference photodiode D _Lref on the left side of the shielding wall, and the drain of the right comparison NMOS transistor is connected to The quantized area photodiodes on the right side of the shielding wall are connected, the gates are interconnected, and the source is grounded;

The reference photodiode is a PN junction photodiode with a preset area on one side of the shielding wall; the quantized area photodiode includes a plurality of PN junction photodiodes with different areas.

The size of the PN junction photodiodes on both sides of the shielding wall in the light sensing unit is consistent, and when the incident light is irradiated on the shielding wall to produce shadows, the area of the PN junction photodiodes on both sides of the shielding wall that can be illuminated by the light source is equal to Not the same, the generated current is not the same.

The photodiode is a PN junction photodiode formed by an N well on a P-type substrate and a P+ doped layer of the N well;

The shielding wall is a metal wall, which is formed by stacking metal layers, metal contact holes and via holes provided by the integrated circuit process.

In the angle detection circuit, there is a certain mapping relationship between the digital output of the left current mirror and the right current mirror and the incident angle of light, and the light is determined according to the mapping relationship between the digital signal output by the left current mirror and the right current mirror and the angle. angle of incidence.

The mapping relationship between the digital signal and the angle is estimated first, and then finally calibrated by the actual detection data, and the corresponding relationship is constructed into a database as the basis for the measurement of the incident angle θ of the light source;

The resolution of angle measurement in the angle detection module is determined by the number of photodiodes of different areas in the light sensing array. With the increase of the number of photodiodes, the area difference of photodiodes with different quantized areas on both sides of the shielding wall decreases, and the digital output of the current mirror As the number of ends increases, the angular resolution increases accordingly.

Each photodiode on one side of the shielding wall has a different area, and one (but not limited to this) simple case is: the area of the PN junction of the smallest light sensing unit is regarded as a unit area A, and the The PN junction area of the reference photodiode is 16A, and the PN junction area of the quantized area photodiode is 15A, 13A, 11A, 9A, 7A, 5A, 3A, 1A.

The self-powered single-chip integrated digital sensor can also include a compensation module, and the compensation module includes:

an upward current compensation photodiode connected with the light sensing unit module;

Or a pull-down voltage compensation photodiode connected to the light direction angle detection module.

The N terminal of the upward current compensation photodiode is grounded, and the P terminal is connected to the N terminal of the light sensing unit.

The N terminal of the pull-down low voltage compensation photodiode is connected to the source of the NMOS transistor in the current mirror, and the P terminal is grounded.

The photo-sensing unit module, the light direction angle detection module and the compensation module are manufactured using IC planar technology, including various integrated circuit technologies such as CMOS technology, BICMOS technology, and bipolar technology.

Compared with the prior art, the present invention has the following beneficial technical effects:

The self-powered single-chip integrated digital sensor for light source direction detection provided by the present invention adopts a light sensing unit module that can generate shadows through the blocking wall to detect the incident angle of the light source, and then uses a light sensor to detect the direction and angle of the light source movement. A Flash ADC circuit with a current mirror structure, and the light sensing unit module can supply power to the Flash ADC circuit, thereby realizing the self-power supply of the digital sensor; the photodiode of the light sensing unit module used can use the photovoltaic effect to harvest energy, and at the same time The Flash ADC circuit of the signal detection and processing circuit is integrated on the same chip to complete complex functions. Since the design, production and packaging technologies of integrated circuits are very mature and stable, this type of device is very easy to design and produce. After mass production, the unit cost is very low, the volume and weight are small, and the reliability is high. The computing unit, storage unit, radio frequency circuit, etc. are integrated to realize various functions.

In addition, the characteristics of the incident angle of the light source are detected by the digital signal output by the self-powered Flash ADC, so that the chip can be well integrated with the digital signal system in a large environment, and the portability is very good; thus realizing high integration, low cost, and portability Good self-powered light source direction detection chip.

Furthermore, in order to solve the problem of field effect transistor conduction, a compensation module based on IC planar technology is also proposed, no matter in the case of low threshold value of NMOS transistor _ML/Rref (<0.4V), or high threshold value Under normal conditions (>0.4V), the entire light source direction detection chip can work by itself, realizing the characteristics of self-power supply, which makes it have great application prospects in the field of low-power and zero-power photosensor devices.

Description of drawings

FIG. 1 is a schematic structural diagram of an optical sensing unit module;

Fig. 2 is a schematic diagram of arrangement of light sensing unit modules;

Figure 3 is a schematic diagram of the quantification of the PN junction area on both sides of the metal wall;

Figure 4 is a schematic diagram of the self-powered Flash ADC circuit measuring the angle of incident light;

Figure 5 Mapping relationship between digital signal output and incident light angle

Figure 6 is an upward current compensation scheme and corresponding schematic diagram based on IC planar technology;

Figure 7 is a pull-down low voltage compensation scheme and schematic diagram based on IC planar technology;

Detailed ways

The present invention will be further described in detail below in conjunction with specific embodiments, which are explanations of the present invention rather than limitations.

The self-powered single-chip integrated digital sensor for light source direction detection provided by the present invention includes a light sensing unit module and a light direction angle detection module, and the IC plane manufacturing technology that can be used includes CMOS technology, BICMOS technology, bipolar technology, etc. The integrated circuit technology will be described in detail below in conjunction with the CMOS technology.

The photosensitive unit module includes photosensitive units arranged in an array on a P-type substrate; each photosensitive unit includes a blocking wall and two or more photodiodes symmetrically arranged on both sides thereof; the described The photodiode is a PN junction photodiode composed of an N well on a P-type substrate and a P+ doped layer of the N well;

Described light direction angle detection module comprises the Flash ADC circuit of current mirror structure, and this FlashADC circuit comprises the left side current mirror of output digital signal and the right side current mirror;

The left current mirror includes a left reference NMOS transistor and a left comparison NMOS transistor, the drain of the left reference NMOS transistor is connected to the reference photodiode D _Rref on the right side of the shielding wall, and the drain of the left comparison NMOS transistor is connected to the left reference NMOS transistor. The quantized area photodiodes on the left side of the shielding wall are connected, the gates are interconnected, and the source is grounded;

The right current mirror includes a right reference NMOS transistor and a right comparison NMOS transistor, the drain of the right reference NMOS transistor is connected to the reference photodiode D _Lref on the left side of the shielding wall, and the drain of the right comparison NMOS transistor is connected to The quantized area photodiodes on the right side of the shielding wall are connected, the gates are interconnected, and the source is grounded;

The reference photodiode is a PN junction photodiode with the largest area (or a certain area) on one side of the barrier wall; the quantified area photodiode includes multiple PN junction photodiodes with different areas.

As shown in Figure 1, the light sensing device model includes a plurality of light sensing units, each light sensing unit includes a P-type substrate 4 and an N well 3 fabricated on the substrate, and the N well 3 is provided with a shielding wall 2, two The photodiodes are distributed symmetrically with respect to the shielding wall 2; the photodiodes are PN junction photodiodes D _Li/Ri formed by the P+ doped layer 1 and the N well 3 in the N well 3 . In the light sensing unit, the N well is directly grounded, ignoring the parasitic current I _DS generated by the PN junction between the P substrate 4 and the N well 3 .

The sizes of the P+ doped layers of the photodiodes on both sides of the shielding wall are consistent; when the incident light irradiates on the shielding wall to produce shadows, the photodiodes on both sides of the shielding wall can have different areas illuminated by the light source. The generated current is also different.

The shielding wall is a metal wall, which is formed by stacking metal layers, metal contacts and through holes allowed by the integrated circuit technology.

Figure 2 is a micrograph of a self-powered monolithic integrated digital sensor that has been fabricated for light source direction detection. It can be seen from Figure 2 that the photodiodes are arranged in an array and connected in parallel with each other;

The angle detection circuit is connected with the photodiode array to output a digital signal, wherein the angle detection circuit is also blocked by a metal plate, in order to make the angle detection circuit work normally without being affected by light.

Figure 3 and Figure 4 show that the current mirror comparison structure is used to directly convert the angle information of the incident light into a digital signal output, and use the mapping relationship between the output digital signal and the angle to determine the incident angle of light. Figure 3 shows a schematic diagram of the quantification of the PN junction area on both sides of the metal wall, and Figure 4 shows the schematic diagram of the self-powered Flash ADC circuit measuring the angle of incident light. Referring to Figure 3, first quantify the area of the P-doped region on both sides of the metal wall, Assume that the maximum area of photodiodes on one side of the metal wall is 16 unit area A, and then set up photodiodes with PN junction areas quantified as 15A, 13A, 11A, 9A, 7A, 5A, 3A, and 1A;

Referring to the upper figure of Figure 3, when the light is slanted to the left, a shadow area is generated on the right side of the baffle, and the current generated by the 16A PN junction D _Lref , which is the largest area on the left side of the baffle, is used as a reference, that is, its current is used as the NMOS transistor M The source-leakage current of _Lref ; and then respectively quantify the areas on the right side of the baffle 15A, 13A, 11A, 9A, 7A, 5A, 3A, 1A of the PN junctions D _R0 , D _R1 ... D _R7 The current generated by the light is the NMOS tube M The source-drain current of _R0 ... M _R7 ; the NMOS transistors M _R0 ... M _R7 are connected in parallel, that is, their gates are interconnected and their sources are grounded to form a right current mirror structure;

Take the current generated by the PN junction D _Rref with the largest area on the right side of the baffle as a reference, that is, use its current as the source-leakage current of the NMOS transistor _MRref ; then quantify the areas on the left side of the baffle to 15A, 13A, and 11A , 9A, 7A, 5A, 3A, and 1A PN junctions D _L0 , D _L1 ... D _L7 light-generating currents are the source-drain currents of NMOS transistors M _L0 ... M _L7 ; the NMOS transistors M _L0 ... M _L7 are connected in parallel, that is, The gate is interconnected and the source is grounded to form a left current mirror structure;

When the current mirror structure on the right is used for current comparison, since the shaded area is on the right side, the current generated by the shaded area on the right cannot be larger than the photocurrent generated by the left reference, that is, the maximum area of 16A fully illuminated area, then R0...R7 The output is all 0, and the light source is incident from the left;

When the current mirror structure on the left side is used for current comparison, although the shaded area is on the right side at this time, the reference area on the right side, which is the maximum area of 16A, generates current. However, as the area of the diode on the left side gradually decreases, when the diode on the left side When the area decreases to a certain value and is slightly larger than the illuminated area of the right reference, the current values generated by the two are nearly equal. At this time, the output of the NMOS transistor corresponding to the left diode is 1, so when the area is larger than the diode, its corresponding The output of the NMOS tube is 1, and the area is smaller than the diode, and the corresponding NMOS tube output is 0, so there is a certain mapping relationship between the digital output of the left current mirror and the illuminated area of the right reference, that is, the digital output of the left current mirror There is a certain mapping relationship with the incident angle of light.

Correspondingly, when the light is oblique to the right, the output of the above-mentioned left current mirror L0...L7 is all 0, and when the output of a certain port on the right is reversed to 1, it means that the current generated by the photodiode on the right port is equivalent to the reference current with shadow on the left. There is a certain mapping relationship between the digital output of the current mirror on the right and the incident angle of light, and the incident angle of light can be determined according to the mapping relationship between the digital signal output on the right and the angle.

In general, assuming that the area of the PN junction of the smallest photo-sensing unit is taken as the unit area A, multiple photo-sensing units are connected in parallel to realize the quantification of the PN junction area on both sides of the metal baffle, so that the maximum total area on one side of the metal wall 16A (if the largest total area is required), the PN junction area on both sides of the baffle is quantified as 15A, 13A, 11A, 9A, 7A, 5A, 3A, and 1A. Taking the current generated by the PN junction with the largest area on both sides of the baffle as the left and right reference, as shown in Figure 3, by comparing the photocurrent generated by the quantized area on the left with the reference current on the right, the photocurrent generated by the PN junction of the quantized area on the right is compared with the photocurrent generated by the left quantized area. Compared with the reference current, the incident angle of light is determined according to the mapping relationship between the digital signal output by the module and the angle.

Figure 5 shows the corresponding relationship between the digital signal output measured by the experimental data and the incident light angle. It can be seen that when the incident angle θ (refer to Figure 1) is a positive value (that is, the light is oblique to the left), as shown in Figure 3 , the PN junction of the 16A area on the left side of the baffle as a reference is fully illuminated, and the photocurrent generated by it is always greater than that on the right side of the baffle with shadows and areas of 15A, 13A, 11A, 9A, 7A, 5A, 3A, 1APN junction photocurrent, according to the current mirror comparison structure shown in Figure 4, the digital outputs R0...R7 on the right are all 0. As the incident angle θ increases, the shaded area on the right side of the baffle increases, and the photocurrent generated by the PN junction with an area of 16 A on the right side as a reference gradually decreases. According to the current comparison structure shown in Figure 4, compared with the right side, the photocurrent gradually decreases. With the reduced reference current, the PN junction area required to produce the same current with full illumination on the left side of the baffle gradually decreases accordingly, so as the angle increases, the output signals L0...L7 on the left side representing photocurrents of different quantized areas are high The more the level is, the L7 to L0 flip to high in turn. From the same reason, it can be deduced that the incident angle θ (refer to Figure 1) is negative (that is, the light is obliquely shooting to the right).

It can also be seen from Figure 5 that the resolution of the incident light angle is 10 degrees, which is related to the size of the photodiode array, that is, the resolution of the angle measurement in the angle detection module is determined by the size of the light sensing unit array; As the area of the diode array increases, the number of quantized areas on both sides of the baffle increases, the number of digital output terminals increases, and the angular resolution will also increase, up to a resolution of 1 to 2 degrees. Specifically, the mapping relationship between the digital signal and the angle is determined by the actual detection data, and the corresponding relationship can be constructed into a database as a basis for measuring the incident angle θ of the light source.

Since the input of the angle detection circuit is a photodiode formed by a PN junction, it can provide a driving voltage of about 0.5V. If a 0.5um CMOS process is used for implementation, the conduction threshold of the MOS field effect transistor in this process is about 0.7 V, in order to keep the conduction of the MOS tube, so that the angle detection circuit can work normally at all times. Therefore, the compensating photodiode is also fabricated based on the IC planar process, and current compensation is performed on the input photodiode or the source voltage of the MOS field effect transistor is pulled down.

The self-powered single-chip integrated digital sensor can also include a compensation module, and the compensation module includes:

The upward current compensation photodiode connected with the light sensing unit module, its N end is grounded, and the P end is connected with the N end of the light sensing unit;

Or a pull-down voltage compensating photodiode connected to the light direction angle detection module, its N terminal is connected to the source of the NMOS transistor in the current mirror, and its P terminal is grounded.

For example, the upward current compensation photodiode is:

The upward current compensation photodiode D P is formed by the P+ doping region and N well on the same P-type substrate as the light sensing unit module, the N well of the upward current compensation photodiode D _P is grounded, the P+ doping region and the light _sensing The N wells of the cells are connected.

The described pull-down low voltage compensation photodiode is:

Make an N well on a P-type substrate, make a P+ doped region in the N well, connect the N well to the source of the NMOS transistor in the current mirror, and both the P-type substrate and the P+ doped region are grounded, and the P+ doped region and N-well form a pull-down voltage compensating photodiode D _P .

FIG. 6 shows an upward current compensation scheme based on an IC planar process. In the light sensing unit shown in Figure 1, based on the same P-type substrate 4, an N well 6 is fabricated, and a P+ doped region 5 is fabricated in the N well (6), and the N well 6 directly grounded. Connect the P+ doped region 5 to the N well 3 of the light sensing unit, and since the newly fabricated P+ doped region 5 and the N well 6 form a photodiode D _P , the upward compensation current I _DP generated by it is injected into the N well in the light sensing unit 3, the currents I _Li and I _Ri of the photodiodes D _Li and _DRi are compensated, and the parasitic current I _DS generated by the parasitic photodiode _DS formed by the P substrate 4 and the N well 3 is also offset. The upward current compensation scheme based on the IC planar process increases the current I Lref/Rref generated by the photodiode D _Lref/Rref as the reference, and makes the bias voltage of the NMOS transistor M _{Lref/Rref in} the self-powered Flash ADC circuit larger, even Its threshold value is high (>0.4V), and it can also remain on all the time, and the entire digital sensor can work normally at all times.

Figure 7 shows the compensation scheme based on the pull-down low voltage generated by the IC planar process. In the photo-sensing unit shown in Figure 1, there are multiple parallel-connected NMOS transistors M _L0/R0 based on the same P-type substrate. ...M _L7/R7 , on the P substrate 4, the N well 9 serving as the drain end of the NMOS transistor, the N well 7 at the source end, and the gate 8 are fabricated, and the N well 9 at the drain end is connected to the P+ doped region 1 of the photosensitive unit , the currents I _L and _{I R generated} by the photodiodes _DL and DR are injected into the drain end 9 of the NMOS tube, and an N well 10 is made on the same P-type substrate, and a P+ doping is made in the N well 10 Region 11 connects the N well 10 and the N well 7 at the source end of the NMOS transistor, the P-type substrate 4 and the P+ doped region 11 are all grounded, and the photodiode D _P formed by the P+ doped region 11 and the N well 10, P Type substrate 4 and photodiode D _S formed by N well 10, the currents I _DP and I _DS generated by them respectively pull down the potential of N well 10, making the source terminal N well 7 of the NMOS transistor connected to it become a negative voltage , so that the bias voltage of the NMOS transistor M _Lref/Rref in the self-powered Flash ADC circuit becomes larger, even if its threshold value is high (>0.4V), it can always be turned on, so that the entire chip can work normally at all times.

The IC plane process adopted by the optical sensing unit module, the light direction angle detection module and the compensation module is not limited to the CMOS process adopted in the present invention, and can also include BICMOS process, bipolar process, etc., as long as the above-mentioned modules are satisfied. structure and function.

Claims (10)

1., for the self-powered single-chip integration digital sensor that light source direction detects, it is characterized in that, comprise photoinduction unit module and light direction angle detection module;

Described photoinduction unit module comprises the optoelectronic induction unit be arranged in arrayed in P type substrate; Each optoelectronic induction unit comprises baffle wall and is symmetricly set on the photodiode of its both sides; The PN junction that described photodiode is formed when being and being contacted with n type material by the P-type material in integrated circuit technology is formed;

Described light direction angle detection module comprises the angle detection circuitry of current-mirror structure, and this angle detection circuitry comprises left current mirror and the right current mirror of output digit signals;

Described left current mirror comprises left side benchmark NMOS tube and NMOS tube is compared in left side, reference light electric diode D on the right side of the drain electrode of left side benchmark NMOS tube and baffle wall _rrefbe connected, left side is compared the drain electrode of NMOS tube and is connected with the quantification area photodiode on the left of baffle wall, gate interconnect, the interconnected ground connection of source electrode;

Described right current mirror comprises right side benchmark NMOS tube and NMOS tube is compared on right side, reference light electric diode D on the left of the drain electrode of right side benchmark NMOS tube and baffle wall _lrefbe connected, right side is compared the drain electrode of NMOS tube and is connected with the quantification area photodiode on the right side of baffle wall, gate interconnect, the interconnected ground connection of source electrode;

Described reference light electric diode is the one-sided PN junction photodiode presetting area of baffle wall; Quantize area photodiode and comprise the different multiple PN junction photodiodes of area.

2. as claimed in claim 1 for the self-powered single-chip integration digital sensor of light source direction detection, it is characterized in that, in described photoinduction unit, the size of the PN junction photodiode of baffle wall both sides is consistent, when incident light be radiated at baffle wall produces shade time, the PN junction photodiode of baffle wall both sides can be different by the area of light source irradiation, the electric current produced is not identical yet.

3. as claimed in claim 1 for the self-powered single-chip integration digital sensor that light source direction detects, it is characterized in that, described baffle wall is metal wall, and being that the metal level, metal contact hole and the via hole that are provided by integrated circuit technology are stacking forms.

4. as claimed in claim 1 for the self-powered single-chip integration digital sensor of light source direction detection, it is characterized in that, in described angle detection circuitry, the numeral of left current mirror, right current mirror exports and there are certain mapping relations with light angle, according to left current mirror, the digital signal of right current mirror output and the mapping relations determination light angle of angle.

5. as claimed in claim 4 for the self-powered single-chip integration digital sensor of light source direction detection, it is characterized in that, described digital signal and the mapping relations of angle are first estimated, detect data by reality more finally to demarcate, its corresponding relation is built into database, using the foundation measured as light source incidence angle θ;

The resolution of measurement of angle in angle detection module is determined by the photodiode number of different area in photoinduction array, along with increasing of photodiode number, the area difference that baffle wall both sides difference quantizes the photodiode of area reduces, current mirror digital output terminal increases, the corresponding raising of angular resolution.

6. as claimed in claim 1 for the self-powered single-chip integration digital sensor of light source direction detection, it is characterized in that, each photodiode of baffle wall side has different areas, wherein a kind of situation is: the area of minimum light sensing unit PN junction is considered as unit area A, the PN junction area of described reference light electric diode is 16A, and the PN junction area quantizing area photodiode is followed successively by 15A, 13A, 11A, 9A, 7A, 5A, 3A, 1A.

7., as claimed in claim 1 for the self-powered single-chip integration digital sensor that light source direction detects, it is characterized in that, described self-powered single-chip integration digital sensor can also comprise compensating module, and described compensating module comprises:

The upwards current compensation photodiode be connected with photoinduction unit module;

Or to be connected with light direction angle detection module pull down low-voltage compensating light electric diode.

8. as claimed in claim 7 for the self-powered single-chip integration digital sensor that light source direction detects, it is characterized in that, the N of described upwards current compensation photodiode holds ground connection, and P end is held with the N of photoinduction unit and is connected.

9., as claimed in claim 7 for the self-powered single-chip integration digital sensor that light source direction detects, it is characterized in that, the described source electrode pulling down NMOS tube in the N termination current mirror of low-voltage compensating light electric diode, P holds ground connection.

10. as claimed in claim 7 for the self-powered single-chip integration digital sensor of light source direction detection, it is characterized in that, the IC planar technology that described photoinduction unit module, light direction angle detection module and compensating module adopt makes, and comprises CMOS technology, BICMOS technique and bipolar technology.