JPS62263424A - Photometric apparatus - Google Patents

Abstract

PURPOSE:To obtain the title apparatus having a simplified structure for splitting incident light and generating no error in spite of the temporal variation of incident light, by using branch type optical fibers independent to each other in the light transmitting paths from a common input terminal to a plurality of output terminals. CONSTITUTION:A branch type optical fiber 2 has a common single input terminal 2a at the focus position of an objective lens 1 and the terminal parts of three branched light transmitting paths 2b-2d are formed to output terminals 2x-2z. Light receiving elements 8x-8z mutually different in spectral sensitivity are arranged in opposed relation to the output terminals 2x-2z. Subsequently, the outputs thereof are individually converted to digital values by A/D converting parts 10x-10z to be outputted and said A/D conversions are simultaneously performed in a control part 12. The generation of the errors of the stimulus values in the light receiving elements 8x-8z is avoided by the branch type optical fiber 2 and, in spite of the timewise variation of incident light, highly accurate measurement can be performed in such a state the ratio of light components is kept constant and a structure for splitting incident light can be simplified.

Description

[Detailed description of the invention] Magical presentation! The present invention receives a plurality of light components having different wavelengths, and receives A/
The present invention relates to a light measuring device such as a spot colorimeter or a multicolor radiation thermometer that obtains data to be input into a microcomputer or the like by D-conversion.

The structure of the Yoshizachi luminance meter is such that a light-receiving element is placed at the focal point of a lens that condenses incident light. In the case of this non-contact spot colorimeter, which is a luminance meter type photoelectric colorimeter,
Three light receiving elements with spectral sensitivities Xλ, yλ, and Tλ are used, and it is necessary to divide the incident light into three parts.

Here, the spectral sensitivities Xλ, yλ, and Tλ are sensitivities that match human vision as defined by the CIE (Commission Internationale de l'Eclairage) XYZ color system.

In addition, chromaticity

Each y is X；□ ・・・・・・・・・・・・・・・・・・・・・
・・・・・・(1) It is found by X+Y+Z, and the tan degree is found by Y.

As described above, in order to make light incident on three light receiving elements having different spectral sensitivities, it is necessary to divide the incident light into three parts. Conventionally, the methods used to split incident light into three wavelength components are: (1) splitting the incident light into three wavelength components using a half mirror, (2) rotating a rotary plate with multiple filters attached, and There is a method in which the incident light is time-divided and the light of each wavelength component is received by an individual light-receiving element.

However, each conventional example of such a method has the following problems.

In the case of the splitting method using a half mirror (2), it is susceptible to adverse optical effects from the lens barrel, causing errors in the stimulus value at each light receiving element, and the mounting position of each light receiving element is adjusted to match the incident optical axis. There are major restrictions on placement that must be strictly determined in relation to the following.

In addition, in the case of the time division method (2), when the incident light changes temporally, the ratio of the three stimulus values changes, which also causes errors. Furthermore, a special motor and motor control unit are required to rotate the rotary plate with a filter, which complicates the structure, and there are problems in that it is difficult to synchronize A/D conversion and motor rotation. be.

The present invention has been made in view of these circumstances, and it simplifies the TL structure for dividing incident light, relaxes restrictions on the arrangement of light receiving elements, and furthermore An object of the present invention is to provide an optical measuring device that does not cause errors in measured values even if the measured values vary.

The present invention for determining the fortune by 2° has the following configuration in order to solve the above-mentioned problems.

That is, the optical measurement device of the present invention includes: a branched optical fiber having a common input end and a plurality of output ends, and in which optical transmission paths from the input end to each of the output ends are mutually independent; and the branched optical fiber. A plurality of light receiving elements that are arranged to face each output end and have different spectral sensitivities, and a plurality of A/D converters that individually A/D convert the outputs of the plurality of light receiving elements and output the results. and a control section that causes the plurality of A/D conversion sections to perform A/D conversion simultaneously.

Tachi-ri The effects of this configuration are as follows.

In other words, to split the incident light into multiple parts, we use branched optical fibers in which the optical transmission paths from a common input end to multiple output ends are mutually independent. There is no need to receive any adverse optical influence from the lens barrel that has been removed, and the occurrence of errors in stimulus values in each light receiving element is avoided. Further, since the branched optical fiber has a high degree of freedom in bending, restrictions on the arrangement of each light receiving element are relaxed.

In addition, the configuration is such that a branched optical fiber is used so that light enters multiple light receiving elements at the same time, and the controller is configured to simultaneously perform A/D conversion of multiple A/D conversion units. Therefore, even if the incident light changes over time, the ratio between multiple stimulus values will not change.
The plurality of data obtained by simultaneous A/D conversion becomes accurate data that is not affected by temporal fluctuations of incident light.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Below, an embodiment in which the present invention is applied to a three-part type non-contact spot colorimeter will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a non-contact spot colorimeter.

In FIG. 1, l denotes an objective lens, and 2 denotes an optical transmission line 2b, 2c which has a common single input end 2a at the focal position of the objective lens 1 and is branched into three.

This is a branched optical fiber in which the ends of 2d are formed as output ends 2x, 2y, and 2z. 2 on the front of input 81a2a
Two mask plates 3a, 3b are arranged, both mask plates 3a,
A vibrating type chopper 4 is arranged between the parts 3b. 5 is a motor that vibrates the chopper 4, 6 is a CPU 12
This is a motor control section that controls the motor 5 using three motor control signals from the motor controller.

7x, 7y, and 7z are output terminals 2X, respectively.

The filters 8x=87.8z, which have different transmission wavelengths and are placed opposite to 2y and 22, are
These are light receiving elements arranged facing the filters 7x, 7y, and 7z, respectively. The spectral sensitivity Xλ is defined by the characteristics of the filter 7x and the light receiving element 8x, the spectral sensitivity yλ is defined by the characteristics of the filter 7y and the light receiving element 8y, and the spectral sensitivity Xλ is defined by the characteristics of the filter 7z and the light receiving element 8z.
is stipulated.

9x, 9y, and 9z are light receiving elements 8x, respectively.

8y, I- which linearly converts the current generated at 82 into voltage.
This is a photoelectric conversion section consisting of a V conversion circuit. The photoelectric conversion unit 9y that outputs the stimulus value Y corresponding to the luminance has four ranges and is range-controlled by the range switching signal S++c+ from the CPtJ12. The photoelectric conversion unit 9 that outputs the stimulus values X and Z has three ranges 92, and receives a range switching signal Ss from the CPU 12. range controlled by.

10x, 10V, and 10z are photoelectric conversion units 9x, respectively.

Signal SX of stimulus values x, y, z input from 931.92
This is a double integral type A/D converter that converts l+ '''Vl+ Sz+ into A/D.These double integral type A/D converters
The conversion units 10x, 10y, and 10z each have a CPU 12.
The integration operation is started by the integration signal 5eNt from C.
The inverse integration is started by the inverse integration signal 5AIII from the PU12, and the reset signal S from the CPU12.

reset by .

11 is a counter llx for three A/D conversions, 11)
'.

ttz, and these counters 11
x, 11y, 11z are each A/D
Conversion unit 10x.

10y, 10z output signal S *** S Y3+
This is to simultaneously count Szz and send it to the CPU 12.

The output signals SX3+Sv3+S23 of the A/D converters 10x, 107, and 102 are an AND gate AN
D+, AND gate AND, CPU
12, the A/D conversion end signal S! ,llll.

The double integral type A/D converters 10x, 10y, and 10z are all constructed as shown in FIG.

That is, an integrating circuit INT and a comparator C whose non-inverting input terminal (+) is connected to the output terminal of this integrating circuit rNT.
Signal SXI (Sv+,
It is composed of an integral switch Is that inputs Sz+) to start an integral operation, an inverse integral switch AIS that causes an integrator circuit INT to start an inverse integral operation, and a constant current circuit CI connected to this inverse integral switch AIS. There is.

The integrating circuit INT includes an operational amplifier oP, an integrating capacitor C connected between the inverting input terminal (-) and the output terminal of the operational amplifier OP, and a reset switch R3 connected in parallel to the integrating capacitor C. It is configured.

A signal SX s + S v , +322 is output from the output terminal of each comparator COM in each A/D converter 10 x , 101 , 102 to each counter 11 x , 11 )', 11 z.

The CPU 12: ■ A of all A/D converters 10x, 10y, 102;
/D conversion unit 10 at the timing when the D conversion is completed.
At the same time, a reset signal S is outputted to each of the reset switches R3 of , the integral signal S1 is simultaneously applied to each integral switch Is.
．． 7 and ■ Integral signal SIN? When a predetermined period of time has elapsed after the output of
, 11 y , 11 z simultaneously outputs a count start signal Ssv, ■ all A/D converters 10 x , 10 y ,
It is configured to cyclically perform an operation of reading count values from each counter 11x, lly, and llz at the timing when A/D conversion of 10z is completed.

13y shown in FIG. 1 is a Y-beak over determination unit that determines whether the signal SVI of the stimulus value Y from the photoelectric conversion unit 9y exceeds a predetermined value, and 13xz is a Y-beak over determination unit that determines whether the signal SVI of the stimulus value Y from the photoelectric conversion unit 9y exceeds a predetermined value. Signal SII+ of values X, Z
This is an Xz beak over determination unit that determines whether SK+ exceeds a predetermined value. The Y peak over determination section 13y and the XZ peak over determination section 13xz receive an integral signal SIN? from the CPU 12. 7! l
<''Perform the over judgment operation during the H° level period.

14) F is an integrating circuit INT in the A/D converter 10y
14XZ Y integral over determination unit that determines whether the integral output Svt from exceeds a predetermined value;
is the integral output SX! from each integrating circuit INT in the two A/D converters 10x and 10z! + szz is an XZa excess determination unit that determines whether or not szz exceeds a predetermined value.

OR, is made conductive by the peak over determination signal s pov from the Y peak over determination section 13y or the over integration determination signal s toy from the Y integral over determination section 14y, and outputs an over determination signal S' to the CPU 12.
This is an OR gate that outputs OV. 0Rt is a peak over determination signal S from the XZ peak over determination section 13xz. , □ or XZ integration over determination section 14xz
The over-integration determination signal 5IOX□ from the input signal 5IOX□ conducts the over-integration determination signal S to the CPU 12. This is an OR gate that outputs X□.

15 is a display device connected to the CPU 12; 16
is a photometric switch.

<Operation> Next, the operation of this non-contact spot colorimeter will be explained based on the time chart of FIG.

Light from the object to be measured enters the input end 2a of the branched optical fiber 2 through the objective lens l.

This incident light is interrupted by the chopping operation of the chopper 4. That is, the motor control signal 8.4 is intermittently outputted from the CPU 12, and based on this, the motor control section 6.
This is because the motor 5 is driven intermittently. s"ro is a photometry period (measurement light incident period), and T is a light shielding period.

The light incident on the input end 2a is transmitted through three optical transmission lines 2b.

Divided into three by 2c and 2d, each output end 2X.

2y and 2z, the light enters each light receiving element 8x, 8y, and 8z via filters 7x and 77.7z.

Since the filter 7x and the light receiving element 8x define the spectral intensity Xλ related to the stimulus value X, the light receiving element 8x has the stimulus value X.
Light corresponding to is incident. Similarly, light corresponding to the stimulus value Y is incident on the light receiving element 8y, and light corresponding to the stimulus value Z is incident on the light receiving element 8z. Each of these light receiving elements 8x, a
Light corresponding to the stimulus values x, y, and z are incident on y and 8z at the same time.

The light receiving element 8x generates a current corresponding to the stimulus value X, this current is converted into a voltage by the photoelectric converter 9x, and the signal 5llll for the stimulus 4g1x is sent to the A/D converter 10.
Output to x. Similarly, the signal S□ for the stimulus value Y is output to the A/D converter 10y, and the signal SKI for the stimulus value Z is output to the A/D converter 10z.

Period t,~t! In CPtJ12, all A
A reset signal S is output to the /D converters 10x, 10Y, and 10z. During this period, there is no output of the integral signal SIN A and the inverse integral signal sA+wt. A/D converter 10x, 1 by reset signal S,
0y.

Each reset switch R3 in 10z is turned on,
The charge in each integrating capacitor C is completely discharged.

In the next period t, ~(, CPtJ12 converts all A/D converters 10 x , 10 y , 10 z
An integral signal 5INT is output for that. In this period,
Inverse integral signal 5AIN? And there is no output of the reset signal Sll.

A/D converter 10x, 1 according to integral signals SI and IT
0y.

Each integral switch Is at 10z is turned on, and the signals S X I +Sv from the photoelectric conversion units 9x, 9y, and 9z
, ,S, , the negative polarity charging of each integrating capacitor C is started simultaneously, and the output S of each integrating circuit INT. +
Svt+Szz decreases linearly.

Since these outputs are below 0 [v], the output of each comparator COM S X31 S vs+ S z*
becomes 'L' level. This integration period t0 is the same for all A/D converters 10x, joy, and 10z.

Therefore, even if the incident light changes over time, the tristimulus values X, Y
, Z, the mutual ratio does not change.

At time t3, the output of the integral signal 5lll is stopped to stop the integral operation. During periods t, -t, integral signal Sl+1'r+inverse integral signal Sa+2. and the reset signal S all become 'L' level. Then, during this period t, to t4, the Y peak over determination section 1
3y, Y integral over determination section 14y and XZ peak over determination section 13XZ, X2 integral over determination section 1
4xz is driven to make each over judgment.

If there is an over in the Y peak over determination section 13y, the peak over determination signal SPOV makes the OR gate OR+ conductive.

An over determination signal S is sent to the CPU 12 from the CPU 12. V is output. As a result, the CPU 12 outputs a range switching signal 5tcr to the photoelectric conversion section 9y, and switches the range of the photoelectric conversion section 9y so that the level of the signal SVI from the photoelectric conversion section 9y falls within the appropriate range. Y-integration over determination unit 14
If there is an over-integration in y, the over-integration determination signal 5
IOV is OR gate.

is made conductive, and the range of the photoelectric conversion unit 9y is switched in the same manner as described above.

Furthermore, if there is an over in the xZ peak over determination section 13χ2, the peak over determination signal S P2
N2 makes OR gate OR2 conductive, and OR gate OR,
An over-determination signal 5OXZ is output from the CPU 12 to the CPU 12. As a result, the CPU 12 sends a range switching signal S Ic! to the photoelectric conversion units 9x and 9z. The signal 5XIIS! from the photoelectric conversion units 9x and 9z is output. Light 1 so that I's level falls within the appropriate range! Switch the ranges of converters 9x and 9z. If there is an over-integration in the Xz over-integration determination section 14x2, an over-integration determination signal S, is generated. , 2 is OR
The gate aRt is made conductive, and the photoelectric conversion section 9x is turned on as described above.
, change the range of 9z.

When there is an overflow in this way, after switching the range, A/D conversion is started again.

And when there is no over judgment, time'lrl L
At a, the CPU 12 outputs the inverse integral signal 5AIN? A/
It outputs to each inverse integral switch AtS of the D converter 10x, 1031, 10z, and also outputs to each counter II.
x,tiy.

A count start signal SSV is output to 11z.

Each inverse integral switch AI
s is ONL, and the charge charged in each integrating capacitor C is discharged via each constant current circuit CI. That is, positive charging of the integrating capacitor C is simultaneously started as inverse integration, and the output SX! of the integrating circuit INT! , SYt+32ffi increases linearly, and its output S buy2. SYt+
Since szt is still below O(V), the output 5X31 Sr1°S23 of each comparator COM is “L”.
Maintain the level.

On the other hand, each counter 11 x , 11 Y , 11
z starts counting in response to a count start signal SST. This count is the output s of each comparator COM
xs.

This is performed only during the period when Sr5.32m is at "L" level.

Output SX of each integrating circuit INT by inverse integration! .

SYz and szi reach 0 [v], but the time differs depending on the magnitude of the output S xz+ S vt+ S zt of the integrating circuit [NT in each A/D converter 10x, 10y, 10z. However, in any case, the output of the integrating circuit INT S Ill S vt+ S
When zz reaches 0 (V), the output of comparator COM switches to H” level, and at that time, AN
The D gate AND becomes conductive and the AID conversion end signal is output.
is output to the CPU 12. Counters llx, lly.

112 ends counting when each comparator signal reaches the "H° level."

The CPU 12 determines that the outputs of all comparators COM are “
At time t when the inverse integral signal 5A becomes H” level,
Stop the output of IN↑. And this time 1. , each counter 11 x , 11 V , 11 z
The count value is read into the CPU 12.

With the above steps, one cycle of the photometry period T0 is completed.

The count values of each counter 11 x , 11 y , 11 z are calculated by the corresponding comparator COM
This is the count value in the "L" level state of , and this corresponds to the size of each person's chi 3 5XII Sv++ 321.

During the light-blocking period T0, the chamber 4 blocks light from entering the object to be measured.

In order to correct errors due to circuit offset, measurements are also taken during the light shielding period T. Its operation consists of a photometry period T,
The same is true for .

Note that under conditions where there is no concern about errors due to circuit offset, the measurement during the light shielding period T6 may be omitted.

Next, details of the operation of the CPU 12, which controls the above operations, will be explained based on the flowchart of FIG. 4.

When the photometry switch 16 is turned on, the operation starts from step #1. In step #1, photoelectric conversion IB9x
, 9y, 9g.
By outputting , the motor 5 is driven and the chipper 4 is opened. At step #3, a reset signal Syo is output to each reset switch R3. In step #4, idling for a predetermined time is performed, step #5
And each A/D converter 10 x , 10 Y , 10
At the same time, an integral signal S1□ is output to z, and an integral operation is executed.

In step #6, the Y peak over determination unit 13y.

The Y-integration over-determination unit 14y, the XZ peak-over-determination unit 13xz, and the XZ-integration over-determination unit 14χ2 perform overdetermination. When it is determined that no overage has occurred, proceed to step #7. , each A
The inverse integral signal sa+Nt is output to the /D converters 10x, 10y, and 102. In step #8, each counter 1
At step #9, the count values of 1x, 11y, and 11z are read, and the motor control signal S is output to reverse the motor 5 and close the chopper 4. In step #lO, each A/D converter fox.

10)', output a reset signal SR to 10z,
Discharge each integrating capacitor C. In step #ll, idling is performed for a predetermined period of time. In step #12, an integral operation is performed in the light-shielded state, and in step #13, inverse integration is performed. In step #14, counter 11 x
, 11 Y, and 11 z. In step #15, each count value in the shading period T is subtracted from each count value in the photometry period T0 to perform zero point correction.

In the over determination in step #6, if there is an over, the process jumps from step #6 to step #16.

In step #16, a range determination subroutine is executed, and in step #17, it is determined whether the range should be changed. If no changes are necessary, proceed to step #18.
Then, a subroutine for calculating luminance Y and chromaticity x and z is executed, and in step #19, the calculation results are displayed on the display device W15, and the process returns to step #2.

If it is determined in step #17 that the range should be changed, the process moves to step #20, executes the range setting subroutine, and returns to step #2.

Note that the present invention may be applied to a multicolor radiation thermometer,
Number of branches of branch type optical fiber, filter.

The number of light receiving elements etc. may be 2 or 4 or more.

Fourth coming According to the present invention, the following effects are achieved.

Since the optical transmission path from a common input terminal to multiple output terminals uses branched optical fibers that are independent from each other, there is no optical influence from the surroundings, and errors in stimulus values at each light receiving element are avoided. can.

Moreover, because the branched optical fiber allows light to enter each light-receiving element at the same time, and the output of each light-receiving element is A/D-converted at the same time, regardless of temporal fluctuations in the incident light,
Highly accurate measurement can be performed while keeping the ratio of each light component constant.

Furthermore, by employing a branched optical fiber, the structure for splitting the incident light can be made into an hour wheel, and the degree of freedom in arranging the light receiving element can be expanded.

[Brief explanation of drawings]

Figures 1 to 4 relate to embodiments of the present invention, with Figure 1 being a block diagram of a non-contact spot colorimeter, Figure 2 being a block diagram of a double-integration type A/D converter, The figure is a time chart for explaining the operation, and FIG. 4 is a flow chart for explaining the operation. 2... Branch type optical fiber 2a... Input end 'lb, 2C, 2d... Optical transmission line 2x, 2y, 2z... Output end 9x, 8y, 8z... Light receiving element 10x, toy, 10z =・AID converter 12...
CPU (control unit) Applicant Minolta Camera Co., Ltd. Agent Patent attorney Oka 1) Hidedai Kazu 2 Figure D5X2 (SY2,522)

Claims (1)

[Claims] (1) A branched optical fiber having a common input end and a plurality of output ends, in which optical transmission paths from the input end to each of the output ends are independent from each other, and a state in which the branched optical fiber faces each output end of the branched optical fiber. a plurality of light-receiving elements arranged in the same direction and having different spectral sensitivities; a plurality of A/D converters that individually A/D-convert the outputs of the plurality of light-receiving elements and output the A/D converters; An optical measurement device comprising: a control section that causes a D conversion section to simultaneously perform A/D conversion.