JPS62121315A - Display device for measuring instrument - Google Patents

Abstract

PURPOSE:To display a more accurate measured value by displaying a measured signal to be out of a linear processing range by a numerical display and a newly provided optical display element. CONSTITUTION:In case a sensor 10 is a temperature sensor and for instance, the detection is performed in a range of 30-90% humidity, a logarithmic compressor 11 linearizes logarithmic output of the sensor 10 and a measured signal value is optically displayed by a numerical display element. Next, in case the detection of the sensor 10 is performed in a range of 0-30% humidity, the logarithmic compressor 11 loses the linear ability and outputs the measured signal including an error. This measured signal is converted digitally and optically displayed by the numerical display element and made the numerical display with low reliability. On the other hand, in this measuring process, a comparator 15 is actuated reversely and its high-level output is supplied to a driver 13 for display through an OR gage 22. In this way, the optical display element 14a at the right side is lighted and displays that the numerical display includes the error and further, is of a low-humidity area.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Use" This invention is applicable to +1 constant devices such as thermometers, hygrometers, barometers (e.g., pressure gauges), and photometers (e.g., exposure meters). The present invention relates to an optical display device.

"Prior Art" Digital optical display devices are widely known as display devices for measuring instruments such as hygrometers and photometers.

FIG. 5 is an example of an exposure display device provided in a photographic camera. This exposure display device inputs an optical information voltage sent as an analog voltage and converts it into a digital converter 11. The light emitting diodes DI, D211111, Dn light up according to the output of this converter 1, and the optical information voltage becomes overscale. It is composed of a comparator 2 which inverts its output to a low level when the voltage becomes low, and a transistor 3 which turns off in response to the low level output of the comparator 2.

The light emitting diodes D1, D2111, and Dn are sequentially lit according to the level of the optical information voltage to display the aperture value or shutter time.

The light emitting diodes DI, D211, and Dn are arranged in the finder, and the photometry results are often determined by looking through the finder.

In case of scale over, light emitting diode D1
Alternatively, one of the light emitting diodes Dn is configured to light up continuously, but in the case where the reference voltage of the comparator 2 is set to a pulse voltage in response to scale over, the light emitting diode D
1 or Dn repeats blinking, indicating that the scale is out from this display state.

As scale-out display means, there are those that are configured to light up a separately provided light emitting diode, and those that use an LCD (liquid crystal display element) as an optical display element.

"Problems to be Solved by the Invention" As mentioned above, conventional exposure display devices perform optical display within a display range determined by the number of display elements, specifically, the number of light emitting diodes, and optical display at a scale beyond this display range. Out optical display is possible.

However, since the display is uniform regardless of the error in the sensor output, that is, the optical information input to the A-D converter 1, the device displays accurate measured values over a wide range. This is not necessarily desirable.

In the case of the above display device, since the output signal of the photoelectric converter changes logarithmically with respect to changes in the brightness of the subject, this output signal is linearized by logarithmic compression processing, and the linear signal is sent to the A-D converter. It is configured to be input to

Therefore, the brightness level is displayed fairly accurately in the range where it can be linearized accurately, but since there is a range that cannot be linearized with the logarithmic compression processing means, especially for photoelectric conversion signals in low brightness areas and high brightness areas. may be input to the A-D converter 1 as a nonlinear signal, and in this case, an ambiguous display will result.

All nonlinear signal inputs can be displayed as scaled out, but this display is uniform, so it is not appropriate when using measured display values to set conditions for tests or experiments. .

"Means for Solving the Problems" The present invention aims to solve the problems of optical display devices as described above.

Therefore, the present invention provides a sensor that detects physical quantities such as humidity and luminous intensity from an object to be measured and generates an analog measurement signal that changes logarithmically in response to changes in the physical quantity, and an operation that linearizes the measurement signal. In a measuring instrument equipped with a processor and a display that digitally converts the linearized measurement signal and displays the digital measurement signal optically, it is possible to A signal comparator that compares a predetermined signal with the analog measurement signal and outputs an output in accordance with the comparison operation, and a signal comparator that is arranged together with the numerical display element of the display and changes the display according to the output of the signal comparator. We propose a display device provided with an optical display element that allows

According to the present invention, the measurement signal within the linear processing range of the arithmetic processor is displayed by an optical numerical display element, and the measurement signal outside the linear processing range is transmitted by the optical numerical display element and another newly provided optical display element. Each is displayed by a display element, for example a bracket-shaped display element. From this, it is possible to tell at a glance whether a measurement signal that contains almost no error is displayed, or a measurement signal that contains an error. If these are placed on both sides of the numerical display element, the parenthetical display has the meaning of a reference number, so that the error in the measurement signal and the large range of this error can be recognized in accordance with the actual situation.

"Example" Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a display device according to the present invention, in which 10 is a sensor, 11 is a logarithmic compressor, and 12 is an A
-D converter, 13 is a display driver, 14 is a display device,
15, 16, 17, and 18 are comparators that are inverted when the measurement signal reaches a predetermined condition.

The sensor 10 detects a physical quantity from an object to be measured and generates an analog measurement signal that changes logarithmically in response to a change in this physical quantity.

As such a sensor 10, a temperature sensor, a humidity sensor, an atmospheric pressure sensor, a light sensor, and the like are widely known.

As an example, a characteristic curve of a humidity sensor is shown in FIG. This humidity characteristic is plotted with humidity RH (%) on the horizontal axis and impedance (Ω) on the vertical axis.
The condition is that the C1 frequency is 5KHz.

As can be seen from this figure, impedance changes almost logarithmically with changes in humidity.

The logarithmic compressor 11 is a type of arithmetic processor that logarithmically compresses the output signal (or measurement signal) of the sensor 10. Generally, the A-D converter 12 is configured to input a linearly changing signal, and cannot directly input a logarithmically changing measurement signal like the sensor 10 described above.

Therefore, the logarithmic compressor 11 linearizes the output signal of the sensor 10 and converts it into a linear measurement signal.
input to the converter 12.

An example of a circuit widely used as the logarithmic compressor 11 is shown in FIG. This circuit is composed of an operational amplifier 19 (operational amplifier), a diode-connected transistor 20, and a reference voltage source 21, and is configured to input the output signal of the sensor 10. This logarithmic compressor 11 is a transistor 20
Although this configuration performs logarithmic processing using the voltage-current characteristics of , the logarithmic range in which linear characteristics can be obtained is about 100 times.

Therefore, taking a humidity sensor as an example, approximately 30 to 90
% is the range in which linearization can be performed accurately, and linearization processing of sensor output signals falling outside this range, 0 to 30% and 90 to 100%, has extremely low reliability. (Refer to Figure 5) From this, if the output signal of the sensor IO is simply measured and displayed via the logarithmic compressor 11, the sensor output signal included in the above-mentioned ranges of 0 to 30% and 90 to 100% cannot be displayed. This results in many errors in the display. The present invention is characterized in that it is configured so that displays with errors can be recognized at a glance.
This point will be discussed later.

The A-D converter 12 is a known converter that inputs an analog signal from the logarithmic compressor 11 and converts it into a digital signal.
This is a well-known system that inputs a digital signal from 2 to drive an optical digital display 14.

The display device 14 includes a known optical numerical display element (in this embodiment, a two-digit integer display element) and right-hand (open parenthesis-shaped) optical display elements 14a provided on both sides of this numerical display element. and the optical display element 14 on the left side (closed bracket shape)
b. Bracket-shaped display elements 14a, 14b
The colored translucent plate may be illuminated using a light source such as a light emitting diode, or may be constructed using a display element such as an LCD.

The comparators 15 and I6 described above detect the upper and lower limits of the range in which the logarithmic compressor 11 can linearize with high reliability. Taking the humidity sensor as an example, the humidity is approximately 30 to 90%. When a sensor output signal included below the lower limit is input and the logarithmic compressor 11 outputs it, the comparator 15 is inverted to a high level output according to this output, and a sensor output signal included above the upper limit is input to logarithm compressor 11. When the compressor 11 outputs an output, the comparator 16 is inverted to a high level in response to this output.

The comparators 17 and 18 described above are for detecting the upper and lower limits of the numerical display range (O to 99 in this embodiment) of the display 14, and when the sensor output signal is zero or less, the comparators 17 is the logarithmic compressor 11
The comparator 18 is configured to invert to a high level output in accordance with the output of the sensor 18, and when the sensor output signal corresponds to the numerical value display 99 or higher, the comparator 18 inverts to a high level output.

The high level output of comparators 15 and 18 is an OR game.
-22 to the display driver 13, and this driver 13 lights up the optical display element 14a. Similarly, the high level outputs of the comparators 16 and 17 are supplied to the display driver 13 via the OR gate 23, and this driver 13 lights up the optical display element 14b.

FIG. 3 is a characteristic curve of the linearized measurement signal ■1 plotted with humidity RH (%) on the horizontal axis and the measurement signal output from the logarithmic compressor 11 on the vertical axis. El,
E2, E3, and E4 are each of the above-mentioned comparators 15 to 18.
shows the reference voltage of

Next, the operation of the above-described display device will be explained.

Note that in this operation description, it is assumed that the sensor 10 is a humidity sensor.

When the sensor 10 detects the humidity within the range of approximately 30% to 90%, the logarithmic compressor 11 as shown in FIG.
linearizes the logarithmic output signal of sensor 10. Therefore, the linearized measurement signal is digitally converted, and the measurement signal value is optically displayed numerically by the numerical display element. In this case, each comparator 15-18 is in a non-operating state.

When the sensor 10 detects humidity in the range of 0 to 30%, as can be seen from FIG.
loses its linear ability and outputs a measurement signal containing errors. This measurement signal is digitally converted and optically displayed by a numerical display element, but the numerical display has low reliability. On the other hand, during this measurement process, the comparator 15 performs an inverting operation, and its high-level output is supplied to the display driver 13 through the OR gate 22. From this, the right optical display element 14a lights up, and the above-mentioned numerical display power)
It is indicated that the value includes the humidity, and that the numerical value is in a low humidity region.

When the sensor 10 detects humidity in the range of 90 to 99%, as shown in FIG. will be displayed. In this case, since the comparator 16 is inverted to a high level output, the left optical display element 14b lights up, indicating that the numerical display contains an error and that the numerical display is in a high humidity area. do.

If the detected value of the sensor 10 is outside the numerical display range of the display 14, in other words, although such a case does not occur in theory in humidity measurement, the humidity corresponds to zero or less due to an abnormality in the sensor 10, etc. When the output signal is generated, the comparators 15.17 simultaneously become high level outputs, and both the right optical display element 14a and the left optical display element 1.4b light up to indicate their abnormal state.

If the sensor 10 produces an output signal corresponding to 100% humidity or higher, the comparator 16.18
At the same time, the optical display elements 14a and 14b turn on, indicating the abnormal state.

In temperature measurements, etc., the detected value of the sensor 10 may be outside the numerical display range of the display 14, so in such measurements, the optical display elements 14a and 14b are turned on to indicate that the value is outside the numerical display range. It turns out.

In the above embodiment, when the output of the logarithmic compressor 11 deviates from the linear region, causing the optical display element 14a or 14b to light up and become outside the numerical display range of the display 14, these display elements 14a and 14b are simultaneously turned on. Although the configuration is such that the optical display elements 14a and 14b are turned on, the manner in which the optical display elements 14a and 14b are turned on can be changed in various ways. For example, when the output of the logarithmic compressor 11 deviates from the linear region, the two optical display elements 14a, 1
4b may be lit, and when the lower limit of the numerical display range is exceeded, the optical display element 14a may be lit, and when the upper limit is exceeded, the optical display element 14b may be lit. Alternatively, when the numerical display range is outside the numerical display range, the two Optical display element 14a, 1
4b may be configured to blink.

The shapes of the optical display elements 14a and 14b described above are based on mathematical
F The large, medium, and small brackets used can be changed, or modified versions of these brackets can be used.

Furthermore, in the above embodiment, the inputs of the comparators 15 to 18 are taken from the output side of the logarithmic compressor 11; The input voltage level may be determined.

"Effects of the Invention" As described above, in the display device according to the present invention, the measurement signal within the linear processing range of the arithmetic processor is displayed by the optical numerical display element, and the measurement signal outside the linear processing range is displayed as described above. Since the display is configured using a numerical display element and a newly installed optical display element, it is possible to tell at a glance whether a measurement signal that includes an error is displayed or a measurement signal that does not include an error. Furthermore, regarding the newly installed optical display element, by providing it in parentheses on both sides of the numerical display element, the parentheses have the meaning of reference numbers, so the error in the measurement signal and this error can be reduced. It is possible to recognize a large range of information according to the actual situation.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a display device showing an embodiment of the present invention, FIG. 2 is a circuit diagram showing a specific example of a logarithmic compressor, and FIG. 3 is a diagram showing a linearized measurement signal output by the logarithmic compressor. 4 is a diagram showing a characteristic curve of a humidity sensor, and FIG. 5 is a circuit diagram of a conventional camera exposure display device. 10... Sensor 11... Logarithmic compressor 12.
・・A-D converter 13・・Display driver 14・
...Display device 1, 43...Optical display element 14b...Optical display element 15-18...Comparator Patent applicant Stanley Electric Co., Ltd. No. 1-2 Fig. 2゜Fig. 3: 3. Cliff R1-1 ('/,) 4th: View

Claims (3)

[Claims] (1) Detect physical quantities such as humidity and luminous intensity from the object to be measured,
A sensor that generates an analog measurement signal that changes logarithmically with respect to changes in the physical quantity, a processor that linearizes the measurement signal, and a digital conversion of the linearized measurement signal to generate a digital measurement signal. In a measuring instrument equipped with an optical numerical display, a predetermined signal based on the linearization capability limit of the arithmetic processor is compared with the analog measurement signal, and as a result of the comparison operation, A display device comprising: a signal comparator for output; and an optical display element arranged together with a numerical display element of the display to change the display according to the output of the signal comparator. (2) First and second steps for comparing the nonlinear signal with a predetermined signal based on the linearization capability limit of the arithmetic processor in the high level region and low level region of the analog measurement signal described above. A signal comparator is provided, and an optical display element whose display changes according to the output of the first signal comparator is opened, and an optical display element whose display changes according to the output of the second signal comparator is closed. The display device according to claim 1, wherein the parenthesis display elements are formed on both sides of a numerical display element included in the display device. (3) First and second steps for comparing the nonlinear signal with a predetermined signal based on the linearization capability limit of the arithmetic processor in the high level region and low level region of the analog measurement signal described above. A signal comparator is provided, and the optical display element whose display changes according to the output of the first signal comparator is opened in the shape of a parenthesis, and the optical display element whose display changes according to the output of the second signal comparator is closed and the shape of the parenthesis is formed. and these parenthesis display elements are provided on both sides of the numerical display element of the display, and the analog measurement corresponds to the upper limit of the numerical value and the lower limit of the numerical value of the numerical display element of the display device. The display device according to claim 1, further comprising another signal comparator that detects a signal and changes the display of the two parenthesis display elements simultaneously.