JP2000088605A - Absolute position detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small absolute position detector which achieves a lower cost with limited power consumption by providing a low power consumption function to allow immediate computation of an absolute position regardless of any change in the position of an object to be measured during the nonuse period. SOLUTION: This detector is provided with a light shielding plate 11, a reference position sensor S1 to detect origin position slits of the light shielding plate 11, a plurality of relative position sensors S2 and S3 to detect the group of slits of the light shielding plate 11 and a central processing unit(CPU) 15 to compute current absolute positions of the light shielding plate 11 based on a detection signal of the reference position sensor S1 and detection signals from the relative position sensors S2 and S3 when an application signal is inputted. The CPU 15 is provided with a stand by control circuit 20 which outputs a stand by (STB) signal based on the vanishing of the input of the application signal to make the relative position sensor S3 ready for operation based on the STB signal and turns on power sources of remaining other sensors S1 and S2 to set a sleeping state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absolute position detecting device.

[0002]

2. Description of the Related Art A conventional position detecting circuit has many digital sensors or high-precision linear sensors in accordance with the resolution in order to detect an absolute position at any point within an operating range when detecting an absolute position. Or an arrangement in which a small number of reference position sensors and a sensor for detecting a relative position with high resolution are arranged, and an initialization process is performed to detect an absolute position.

[0003] The former case has the advantage that the absolute position can be detected from the time the power is turned on. However, since many sensors and high-precision sensors are used, the cost increases and the sensor mounting is increased. Space is needed.

[0004] On the other hand, in the latter case, the position can be detected with a smaller number of sensors than in the former case, so that there is an advantage that the cost is reduced. An example of the configuration in the latter case will be described with reference to FIG.

[0005] The conventional absolute position detecting device 10 includes a light shielding plate 1.
1. Reference position sensor S1, plural (two in this conventional example)
Relative position sensors S2, S3, photodiode D1,
D2 and D3, and a central processing unit (CPU) 15 are provided. The light-shielding plate 11 is provided integrally with a member to be measured (not shown), and moves together with the movement of the object to be measured (in this conventional example, a linear reciprocating movement orthogonal to the paper surface in FIG. 6).

The photodiodes D1, D2, and D3 are disposed opposite to the reference position sensor S1 and the relative position sensors S2 and S3, which are photo sensors, respectively, with the light shielding plate 11 interposed therebetween. Each photodiode D1, D
2, D3, reference position sensor S1, relative position sensor S2,
In S3, the power supply is controlled by the CPU 15 to turn on and off. That is, when the use signal is input to the CPU 15, the CPU 15 causes the photodiodes D1, D2,
D3, reference position sensor S1, relative position sensor S2, S3
Power supply, and when there is no input of a use signal, the power supply is cut off.

As shown in FIG. 3, one origin position slit 12 is provided at the longitudinal center of the light shielding plate 11, and the origin position slit 12 is arranged so that the photo diode D1 and the reference position sensor S1 can be detected. ing. In addition, light shielding plate 1
A plurality of sets of slits 13 and 14 are provided at predetermined intervals along the longitudinal direction. A pair of slits 13 provided for the relative position sensors S2 and S3,
The 14 groups are formed so as to be out of phase with each other by 90 °. Therefore, when the light shielding plate 11 moves, a signal having a 90 ° phase shift is output from the pair of relative position sensors S2 and S3 as shown in FIG.

In the conventional absolute position detecting device 10, in order to suppress power consumption when not in use, the absolute position detecting device 1 is used.
The power supply to 0 is turned off, and power is supplied only when used. That is, only when used, power is supplied to the photodiodes D1, D2, D3 and the reference position sensors S1, relative position sensors S2, S3, which are sensor units, and power is supplied to the CPU 15. CPU15
Is configured to calculate and output an absolute position when a signal from the reference position sensor S1 is input, but cannot output an absolute position until a signal from the reference position sensor S1 is input. Thus, the CPU 15 can output the absolute position only after the signal from the reference position sensor S1 is input. After the power supply is started,
Until there is an input from the reference position sensor S1, the initialization processing of the absolute position detection device 10 is performed.

[0009] Thereafter, the CPU 15 calculates the amount of movement from the absolute position based on the signals of the two relative position sensors S2 and S3 which are 90 ° out of phase, and outputs the absolute position based on the result.

After the power is turned on,
Until the input from the reference position sensor S1, the absolute position is not output, and only the movement amount based on the signal from the relative position sensor can be output.

[0011]

As described above, in the latter case, the position can be detected with a smaller number of sensors as compared with the former, so that the cost is low. However, since the initialization process is required, There is a problem that the absolute position cannot be detected until the initialization processing is completed. In order to always detect the absolute position, it is necessary to turn on the power to the circuit, and when a battery with limited power is used as the power source, it cannot be used.

In order to solve this problem, there is a system configuration in which absolute position information is stored in a storage means such as a memory provided in the CPU 15 and power is not supplied to a sensor or the like when not in use. However, in this system configuration, when the position of the measurement target moves when not in use, an error corresponding to the movement in the absolute position when not in use is performed until the signal from the reference position sensor S1 is input. There is a problem that arises.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. An absolute position detecting device having a small number of reference position sensors and a relative position sensor has a low power consumption function, and has a low power consumption function. Even when the position of the DUT changes, the absolute position can be calculated immediately.
It is an object of the present invention to provide a low-cost, compact, and low-power-consumption absolute position detecting device.

[0014]

Means for Solving the Problems In order to solve the above problems, the invention according to claim 1 is provided movably,
A reference position mark, a detected member having a relative position mark arranged along the moving direction, a reference position detecting means for detecting a reference position mark of the detected member, and a relative position mark group of the detected member. A plurality of relative position detecting means for detecting, when a use signal is input, a detection signal from the reference position detecting means, and a time-based absolute value of the detected member based on the detection signal from the relative position detecting means. An absolute position detecting device having an absolute position calculating means for calculating a position; a standby signal output means for outputting a standby signal based on the absence of use signal input; and the reference position based on the standby signal. A sleep mode in which a predetermined detection means of the detection means and the relative position detection means is set to an operation state, and power supply to the remaining detection means is turned off and a sleep state is set. Control means, a detection signal from the predetermined detection means in a non-sleep state, and a judgment means for judging whether or not the detected member has been moved based on the detection signal; The gist of the invention is an absolute position detection device including a sleep canceling unit that cancels sleep control of the sleep control unit when it is determined that the member has moved.

Note that the sleep state used in this specification refers to a state in which a part or all of the power supply is stopped as compared with the normal operation state, and the function of the means cannot be exhibited. The non-sleep state refers to a state in which part or all of the power to the unit is supplied and the function of the unit can be exhibited.

A second aspect of the present invention is directed to the first aspect of the invention, wherein the operation of the predetermined detecting means by the sleep control means is an intermittent operation. According to a third aspect of the present invention, in the first or second aspect, the predetermined detecting means is an absolute position detecting device which is a relative position detecting means.

According to a fourth aspect of the present invention, there is provided the first to third aspects.
In any one of the above, the determination means includes storage means for storing, as determination reference data, a detection signal of the predetermined detection means immediately before turning off the power of the remaining other means by the sleep control means, The gist of the invention is an absolute position detecting device for comparing and judging the judgment reference data stored in the means and a detection signal of a predetermined detecting means inputted at each time.

The invention according to claim 5 is the invention according to claims 1 to 4.
In any one of the aspects, the gist is that the absolute position calculation means enters a sleep state based on the output of the standby signal.

(Operation) According to the first aspect of the present invention,
According to the first aspect of the present invention, the reference position detecting means detects a reference position mark of the detected member. The relative position position detecting means detects a group of relative position marks of the detected member.
The absolute position calculating means calculates the respective absolute position of the detected member based on the detection signal from the reference position detecting means and the detection signal from the relative position detecting means when a use signal is input. .

When there is no input of the use signal, the standby signal output means outputs a standby signal based on the absence of the use signal. The sleep control unit activates a predetermined detection unit of the reference position detection unit and the relative position detection unit based on the standby signal, and turns off a power supply for the detection of the remaining unit to set a sleep state.

The determining means receives a detection signal from the predetermined detecting means in the non-sleep state and determines whether or not the detected member has been moved based on the detection signal. Sleep canceling means cancels sleep control of the sleep control means when the determining means determines that the detected member has moved.

According to the second aspect of the invention, the sleep control means operates the predetermined detection means intermittently. Thus, the determination unit intermittently inputs the detection signal from the predetermined detection unit in the non-sleep state, and determines whether the detected member has been moved based on the detection signal.

According to the third aspect of the present invention, the predetermined detecting means is a relative position detecting means,
The operation of claim 1 or 2 is realized. According to the invention described in claim 4, the storage means stores the detection signal of the predetermined detection means immediately before turning off the power of the remaining other means by the sleep control means as the determination reference data. Then, the determination means compares the determination reference data stored in the storage means at the time of the determination with the detection signal of the predetermined detection means which is input at each time.

According to the fifth aspect of the present invention, the absolute position calculating means enters the sleep state based on the output of the standby signal, thereby saving power.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an absolute position detecting apparatus for detecting a steering angle of a vehicle according to the present invention will be described below with reference to FIGS. In addition, the conventional example shown in FIG.
Reference position sensor S1, a plurality of (two in this embodiment) relative position sensors S2, S3, photodiodes D1, D
The configurations of D2 and D3 are the same, and the description is omitted.
The light-shielding plate 11 in this embodiment is operatively connected to a steering mechanism (not shown) of a vehicle, and detects a steering angle of the steering according to a steering amount when the steering is operated. It is. The light shielding plate 11
Constituting a member to be detected, 12 constituting a reference position mark,
The slits 13 and 14 form a relative position mark. or,
The reference position sensor S1 constitutes a reference position detecting means, and the relative position sensors S2 and S3 constitute a relative position detecting means.

In this embodiment, a standby control circuit 20 is provided in addition to the CPU 15. The relative position sensor S
2 and the reference position sensor S1 output a detection signal to the CPU 15. On the other hand, the relative position sensor S3 outputs to the standby control circuit 20. The standby control circuit 20 includes a memory 21 as storage means, and stores in the memory 21 the detection state (H level or L level) of the detection signal S3I from the relative position sensor S3, which is input at each time, and updates it. . Then, the standby control circuit 20 outputs the output signal (detection signal) S30 from the relative position sensor S3 to the CPU 1
5 is output. The updating of the memory 21 is stopped when the standby control circuit 20 is switched to the standby mode, and is restarted when the standby control circuit 20 is switched from the standby mode to the always operating mode.

The standby control circuit 20 has a power switch (power supply line) connected to the photodiodes D1 and D2, the relative position sensor S2 and the reference position sensor S1, and a first switch for turning on and off the power supply. The circuit 22 is provided. In the standby control circuit 20, a power line is connected to the photodiode D3 and the relative position sensor S3, and the second switch circuit 23 constantly supplies power to the photodiode D3 and the relative position sensor S3. Switching between a constant supply mode and an intermittent supply mode for intermittent power supply is possible.

The standby control circuit 20 has a CPU 1
When a standby signal (hereinafter, referred to as an STB signal) from the control unit 5 is input, the operation mode is switched from the always-on mode to the standby mode.

In the normal operation mode, the standby control circuit 20 turns on the first switch circuit 22 and constantly supplies power to the photodiodes D1 and D2, the relative position sensor S2 and the reference position sensor S1. I do. In addition, the standby control circuit 20 sets the second switch circuit 23 to the always-supply mode in the always-on mode,
For the photodiode D3 and the relative position sensor S3,
Power is always supplied.

Conversely, in the standby mode, the standby control circuit 20 turns off the first switch circuit 22 to supply power to the photodiodes D1 and D2, the relative position sensor S2 and the reference position sensor S1. Cut off. In the standby mode, the standby control circuit 20 sets the second switch circuit 23 to the intermittent supply mode to set the photodiode D3 and the relative position sensor S3.
Intermittent power supply. That is, the standby control circuit 20 includes a clock circuit (not shown). In the intermittent supply mode, the photodiode D3 and the relative position are set at predetermined time intervals based on the number of clocks of the oscillation signal oscillated by the clock circuit. Power is supplied to the sensor S3.

When switching to the standby mode, the standby control circuit 20 detects the relative state sensor S3 stored in the memory 21 immediately before switching to the standby mode and the relative position sensor S3 after the standby mode. Is compared with a detection signal inputted every predetermined time. When the two detection states match each other, that is, the detection state stored in the memory 21 is an L level signal, and the detection signal just input is the L level signal, or the detection state stored in the memory 21 is an L level signal. If the state is an H level signal and the currently input detection signal is an H level signal,
It is determined that the light shielding plate 11 has not moved. In this case, the standby control circuit 20 continues the standby mode.

If the two detection states do not match, that is, the detection state stored in the memory 21 is an L-level signal, and the detection signal just input is an H-level signal or stored in the memory 21. If the detection state is an H level signal and the currently input detection signal is an L level signal,
It is determined that the light shielding plate 11 has moved. Based on this mismatch determination, the standby control circuit 20 outputs a start signal (hereinafter, referred to as a WU signal) to the CPU 15 and changes the mode from the standby mode to the always-on mode.

Although not shown, the CPU 15 includes a ROM for storing a control program, a RAM as an operation memory, and the like. When a main power is turned on, various circuits in the CPU 15 are initialized according to the control program. And confirm connection with various peripheral devices connected to the CPU 15.

After turning on the main power, the CPU 15 performs an initialization process (startup process in FIG. 4), and then outputs an STB signal to the standby control circuit 15. While the STB signal is being output, the CPU 15 is in a standby state. In the standby state, power is supplied to a circuit for continuing the output of the STB signal and a minimum necessary circuit for recognizing an input of a use signal described later, and the supply of power to other circuits is stopped. It is in the state of doing. After that, when the ignition ON signal is input as a use signal,
The CPU 15 stops outputting the STB signal. When the CPU 15 stops outputting the STB signal and receives a signal from the reference position sensor S1, the reference position is confirmed. The reference position is compared with the relative position sensor S2.
The absolute position at each time is calculated based on the relative position based on the detection signal input from S3.

The CPU 15 outputs an STB signal to the standby control circuit 15 if there is no change in the detection signals from the reference position sensors S1 and S2 for a predetermined time after the input of the use signal is stopped. Have been. Also, C
When the PU 15 receives the WU signal from the standby control circuit 20, the PU 15 exits from the standby state and the sensors S1
Then, the absolute position at each time is calculated based on the signal from S3.

The CPU 15 constitutes absolute position calculation means and standby signal output means. The standby control circuit 20 forms a sleep control unit, a determination unit, and a sleep cancel unit.

Now, the operation of the absolute position detecting device 10 configured as described above will be described with reference to FIGS.
When the main power is turned on as shown in FIG.
Corresponds to the CPU 1 according to the control program stored in the ROM.
In addition to initializing various circuits in 5 (startup processing), connection confirmation with various peripheral devices connected to the CPU 15 is performed. After that, the CPU 15 outputs an STB signal to the standby control circuit 15. When the STB signal is input, the standby control circuit 20 enters a standby mode.

As a result, the standby control circuit 15
The switch circuit 22 is turned off, and the photodiode D
1, D2, relative position sensor S2 and reference position sensor S1
To the photodiode D, the second switch circuit 23 is set to the intermittent supply mode,
3. Intermittent power supply to the relative position sensor S3.

Thereafter, when the CPU 15 inputs an ignition ON signal, the CPU 15 stops outputting the STB signal. As a result, the standby control circuit 20 switches from the standby mode to the always operating mode. The standby control circuit 20 turns on the first switch circuit 22 in the normal operation mode, and sets the photodiode D1,
D2, the relative position sensor S2 and the reference position sensor S1
To the photodiode D3 and the relative position sensor S3 (see FIG. 4) while supplying the power indicated by VA (see VA in FIG. 4) to the photodiode D3 and the relative position sensor S3. VB) is always performed.

As a result, the standby control circuit 20 stores the detection state (H level or L level) of the detection signal from the relative position sensor S3 which is input from time to time in the memory 21 and updates the state. Is output to the CPU 15.

On the other hand, the CPU 15 operates as a reference position sensor S1.
When there is a signal input from, the reference position is confirmed,
The absolute position at each time is calculated based on the reference position and the relative position based on the detection signals input from the relative position sensors S2 and S3.

Then, the CPU 15 sets the reference position sensors S1 and S2 for a predetermined time after the use signal is no longer input.
If there is no change in the detection signal from the standby control circuit 1
5 and outputs an STB signal. When the STB signal is input, the standby control circuit 20 switches to the standby mode, and stops updating the memory 21. That is, the memory 21 stores and holds the detection state data of the relative position sensor S3 immediately before switching to the standby mode.

After switching to the standby mode, the standby control circuit 20 uses the detection state data stored in the memory 21 immediately before the standby mode switching of the relative position sensor S3 as the determination reference data, and uses the same determination reference data and the standby mode. After the start, a comparison is made with a detection signal input from the relative position sensor S3 every predetermined time. If the two detection states match, that is, if the memory 2
1 is an L level signal, the currently input detection signal is an L level signal, or the detection state stored in the memory 21 is an H level signal, and the currently input detection signal is an H level signal. In the case of a signal, it is determined that the light shielding plate 11 has not moved. In this case, the standby control circuit 20 continues the standby mode.

If the two detection states do not match, that is, the detection state stored in the memory 21 is an L level signal, and the currently input detection signal is an H level signal or stored in the memory 21. If the detection state is an H level signal and the currently input detection signal is an L level signal,
It is determined that the light shielding plate 11 has moved. Based on this mismatch determination, the standby control circuit 20 outputs a WU signal to the CPU 15 and changes the mode from the standby mode to the always-on mode.

Hereinafter, similarly, the standby control circuit 20 performs control corresponding to the normal operation mode, and
5 exits the standby state in response to the WU signal and calculates the absolute position again based on the detection signals from the sensors S1, S2, S3.

FIG. 5 is an enlarged view of the "standby" area of FIG. As shown in the figure, when the WU signal is output, VA and VB are always supplied with power after the output of the WU signal. In addition, since the output from the sensor has not changed for a predetermined time, the STB signal is output again.

According to the present embodiment, the following operation and effect can be obtained. (1) In the present embodiment, a light-shielding plate (a member to be detected) which is movably provided and has an origin position slit (reference position mark) 12 and slits (relative position marks) 13 and 14 arranged along the movement direction. 11), a reference position sensor (reference position detecting means) S1 for detecting an origin position slit 12 of the light shielding plate 11, and a plurality of relative position sensors (relative position detecting means) for detecting a group of slits 13 and 14 of the light shielding plate 11.
When the use signal is input, the reference position sensor S1
(Absolute position calculating means) 15 for calculating the respective absolute position of the light-shielding plate 11 based on the detection signal from the CPU and the detection signals from the relative position sensors S2 and S3. The CPU 15 outputs an STB signal based on the absence of the input of the use signal.
A standby control circuit (sleep control unit) 20 that activates the relative position sensor S3 based on the signal, turns off the power of the remaining sensors S1 and S2, and enters a sleep state.
And the standby control circuit 20 includes a relative position sensor S3
Is detected, and it is determined whether or not the light shielding plate 11 is moved based on the detection signal. When it is determined that the light shielding plate 11 is moved, the standby control circuit 20 controls the sensors S1 and S2. The power off state is released.

As a result, even if the position of the light shielding plate 11 changes when not in use, the absolute position can be calculated immediately. In addition, the power consumption can be reduced, and the configuration of a small number of sensors is sufficient. Therefore, the mounting space for the sensors can be reduced, the size can be reduced, and the cost can be reduced. In addition, since power is saved, the battery can be used.

(2) In the present embodiment, the standby control circuit 20 supplies power so that the relative position sensor S3 operates intermittently. For this reason, it is possible to save more power than in the case where power is always supplied.

(3) In the present embodiment, when the standby control circuit 20 is in the standby mode, the relative position sensor S
3 was operated for detection. Since a large number of slits 14 that can be detected by the relative position sensor S3 are provided in the moving direction of the light shielding plate 11, the reference position sensor S1 in which only one origin position slit 12 is to be detected is intermittently operated. In addition, a change in the position of the light shielding plate 11 can be detected with high sensitivity.

(4) In this embodiment, the standby control circuit 20 determines the detection signal of the relative position sensor S3 immediately before the standby control circuit 20 turns off the power supply to the reference position sensor S1 and the relative position sensor S2. A memory 21 for storing data is provided, and the detection state data stored in the memory 21 is used as determination reference data at the time of determination, and the detection signal of the relative position sensor S3 input at each time is compared with the determination reference data. I did it. As a result, when the detection signal of the relative position sensor S3 changes, it can be immediately determined that the light shielding plate 11 has been displaced,
That is, the operation of the steering mechanism can be detected.

(5) In this embodiment, when the CPU (absolute position calculating means) 15 outputs the STB signal,
Reference numeral 15 denotes a state in which power is supplied to a circuit for continuing the output of the STB signal and a minimum necessary circuit for recognizing the input of the use signal, and the supply of power to the other circuits is stopped. As a result, the power consumption of the CPU 15 decreases in the standby state (sleep state), so that power can be saved.

The embodiment of the present invention can be modified as follows in addition to the above embodiment. (1) In the above embodiment, even after the CPU 15 outputs the STB signal to the standby control circuit 20,
Although the configuration is such that the power supply for the operation of 15 is not turned off, the configuration may be such that, after outputting the STB signal to the standby control circuit 20, the operation power supply of the apparatus itself is turned off by software. In this case, compared to the case of the embodiment,
Further, power consumption of the absolute position detection device 10 can be suppressed.

(2) In the above embodiment, the relative position sensor S3 and the photodiode D3 are operated intermittently. However, the reference position sensor S1 and the photodiode D3 are operated intermittently.
One power supply may be performed intermittently.

(3) In the above embodiment, the reference position sensor S1, the relative position sensor S2, and the relative position sensor S2 including the light emitting element of the photodiode and the optical sensor are used, but a magnetic sensor may be used. When a magnetic sensor is used, a plate to be detected is used as a member to be detected instead of the light-shielding plate 11, and a reference position mark and a relative position mark are provided along the direction of movement of the plate to be detected. Is formed by applying a magnetic member by coating or the like.

(4) Also, a plate to be detected as a member to be detected is provided in place of the magnetic sensor of (3), and contacts are arranged on the plate to be detected along the moving direction of the plate to be detected. A reference position sensor having a counter electrode with respect to the contact, and a relative position sensor are arranged, and by the contact of the counter electrode of each sensor with the contact on the detection target plate, whether or not there is conduction is determined. Alternatively, the position may be detected.

(5) In the above embodiment, the relative position sensor S3 immediately before the standby control circuit 20 turns off the power supply to the reference position sensor S1 and the relative position sensor S2.
21 for storing the detection signal of the above as determination reference data
Was prepared. At the time of determination, the memory 21
Is used as the determination reference data, and the detection signal of the relative position sensor S3 input at each time is compared with the determination reference data.

Instead, in the standby mode, the relative position detection sensor S is controlled by the standby control circuit 20.
When the detection operation is intermittently performed at predetermined time intervals, and when the edge detection of the detection signal from the relative position detection S3 is performed within the predetermined time period, it may be determined that the light shielding plate 11 has moved. Good. By doing so, when the detection signal of the relative position sensor S3 changes, the light shielding plate 11 is immediately
Can be determined, that is, the operation of the steering mechanism can be detected. In this case, the standby control circuit 20 of the above embodiment does not require the memory 21, and the configuration can be simplified.

(6) In the above embodiment, the absolute position detecting device is provided with one reference position sensor S1, two relative position sensors S2, S3, but the number is not limited. Instead, the present invention may be embodied in an absolute position detecting device in which the number of relative position sensors is larger than the number of reference position sensors.

(7) In the above embodiment, one relative position sensor is operated intermittently, but two relative position sensors may be used. When two or more relative position sensors are provided, the intermittent operation may be performed with three or more relative position sensors. In this way, it is possible to reduce the error of the absolute position due to the response during use.

Here, in addition to the technical ideas described in the claims, the technical ideas grasped by the above-described embodiments are listed below together with their effects. (1) In any one of claims 1 to 3, the determination unit is configured to detect when the sleep control unit performs the detection operation of the predetermined detection unit at predetermined time intervals.
An absolute position detection device that determines that a detected member has moved when an edge is detected within the predetermined time. With this configuration, when the sleep control unit performs the detection operation at the predetermined time intervals by the sleep control unit, and the edge detection is performed within the predetermined time period, the detected member moves. Is determined. When the detection signal of the detection means changes, it can be immediately determined that the detected member has been displaced.

[0062]

As described in detail above, according to the first to fifth aspects of the present invention, it is possible to immediately calculate the absolute position even if the position of the object to be measured changes when not in use. In addition, the power consumption can be reduced, and the configuration of a small number of sensors is sufficient. Therefore, the mounting space for the sensors can be reduced, the size can be reduced, and the cost can be reduced.

According to the second aspect of the present invention, the sleep control means operates the predetermined detection means intermittently, thereby reducing power consumption. According to the third aspect of the present invention, the predetermined detecting means is a relative position detecting means, so that the operational effects of the first or second aspect can be obtained.

According to the fourth aspect of the present invention, by comparing the judgment reference data stored in the storage means with the detection signal of the predetermined detection means inputted at each time, the detection signal of the predetermined detection means is obtained. When it changes, it can be immediately determined that the detected member has been displaced.

According to the fifth aspect of the present invention, since the absolute position calculating means enters the sleep state based on the output of the STB signal, power can be saved.

[Brief description of the drawings]

FIG. 1 is an electric block circuit diagram of an absolute position detection device according to an embodiment.

FIG. 2 is an explanatory diagram showing a correspondence between each sensor and a photodiode.

FIG. 3 is a diagram showing a correspondence between a slit provided on a light shielding plate and an output waveform of each sensor.

FIG. 4 is a time chart of various signals.

FIG. 5 is a time chart of various signals.

FIG. 6 is an electric block circuit diagram of a conventional absolute position detecting device.

[Description of Signs] 10: Absolute position detecting device, 11: Light shielding plate (constituting a member to be detected), 12: Origin position slit (constituting reference position mark), 13: Slit (constituting relative position mark) CPU 15 (constituting absolute position calculation means and standby signal output means), 20 standby control circuit (constituting sleep control means, determination means and sleep release means), 21 memory (storage) Means, D1, D2, D3 ... photodiode, S
1. Reference position sensor (constituting reference position detecting means), S2 ... Relative position sensor (constituting relative position detecting means), S3 ... Relative position sensor (constituting relative position detecting means).

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F003 AA02 AA04 AA13 AA22 AB02 AC02 AD00 AD05 2F077 AA30 AA33 AA36 NN05 NN23 NN24 NN30 PP11 PP19 QQ05 RR03 TT21 TT24 TT52 TT62 TT82 TT87

Claims (5)

[Claims] 1. A detected member movably provided having a reference position mark, a relative position mark arranged along a moving direction, and a reference position detecting means for detecting a reference position mark of the detected member. A plurality of relative position detection means for detecting a relative position mark group of the detected member; a detection signal from the reference position detection means; and a detection signal from the relative position detection means when a use signal is input. An absolute position calculating means for calculating an absolute position of the detected member based on the input signal based on the input signal. A standby signal output means for outputting a standby signal based on the absence of the input of the use signal. And the reference position detecting means based on the standby signal,
A sleep control unit that sets a predetermined detection unit out of relative position detection units to an operating state, turns off power supply to the remaining detection units and sets a sleep state, and inputs a detection signal from the predetermined detection unit that is not in a sleep state. Determining means for determining whether the detected member has been moved based on the detection signal; and releasing the sleep control of the sleep control means when the determining means determines that the detected member has moved. An absolute position detecting device provided with sleep canceling means. 2. The absolute position detection device according to claim 1, wherein the operation of the predetermined detection means by the sleep control means is an intermittent operation. 3. The absolute position detecting device according to claim 1, wherein said predetermined detecting means is a relative position detecting means. 4. The determination means includes storage means for storing, as determination reference data, a detection signal of the predetermined detection means immediately before turning off the power of the remaining other means by the sleep control means. 4. The absolute position detection device according to claim 1, wherein the determination reference data stored in the storage device is compared with a detection signal of a predetermined detection unit which is input at each time. 5. The absolute position detecting device according to claim 1, wherein said absolute position calculating means enters a sleep state based on output of a standby signal. .