JP3146530B2 - Non-contact height measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact height measuring device which irradiates a measuring object with a minute beam of light and measures the height of the measuring object using the reflected light.

[0002]

2. Description of the Related Art In recent years, a non-contact method using minute beam light has been used for height measurement. The conventional technique will be described below. FIG. 6 shows the principle of a conventional non-contact height measuring device. In FIG. 6, reference numeral 1 denotes a light source for generating a minute light beam, and the minute light beam is focused on the vicinity of the measuring object 3, for example, on a substrate 9 on which the measuring object 3 is mounted. Spot irradiation by the optical system 2 as described above. The vertically reflected light from the measurement target 3 is deflected by the half mirror 4, and the deflected reflected light is collected by the lens system 6. Reference numeral 7 denotes a photoelectric conversion element that detects the defocus of the image generated by the lens system 6 by measuring the center of gravity of the light amount distribution in the radial direction of the image. By measuring the distance between the lens system 6 and the measurement target 3 from the output value of the photoelectric conversion element 7, the measurement target 3
Height is required. The half mirror 4 and the lens 6
In some cases, a ring-shaped light shielding plate for improving the S / N ratio is provided between the systems.

[0003]

However, in the above-described conventional configuration, the center of gravity of the light quantity distribution in the radial direction of the reflected light of the circular pattern must be detected. JP-A-64-499
In this case, a special circular photodiode as disclosed in Japanese Patent Publication No. 03-2003 has to be used, which increases the cost. Further, if the light intensity distribution of the beam light on the photoelectric conversion element varies due to the influence of the surface condition of the measurement object, a measurement error occurs. Furthermore, in order to simultaneously measure and change the measurement range and resolution, as shown in the above-mentioned publication, a plurality of lens systems for condensing reflected lights having different focal lengths must be used.
There were problems such as a complicated structure.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a measuring device for measuring the height of an object to be measured with high accuracy and high speed without contact.

[0005]

In order to achieve this object, a non-contact height measuring apparatus according to the present invention comprises a light source for generating a minute beam light, and an optical system for spot-irradiating an object to be measured with the minute beam light. The reflected light reflected by the object to be measured is irradiated, and passes through a screen on which a plurality of slit lights are formed on a circumference around the optical axis of the reflected light and each slit hole of the screen. of each of the reflected light
Corresponding to each of the light beam passed through the lens system, the lens system for converging the light beam on the optical axis of the reflected light
Electrical output according to the position where the light beam is received
And a plurality of one-dimensional position detecting elements for generating
Performs a predetermined operation from the output of the one-dimensional position detecting element.
Thus, the height of the measurement object is calculated.

[0006]

In this configuration, the photoelectric conversion element only needs to be able to receive each of the light beams after passing through the screen.
It may be a general one that detects a light receiving position of light in one-dimensional direction. In addition, since the photoelectric conversion elements are arranged at positions corresponding to the respective luminous fluxes after passing through the screen, it is possible to detect heights from multiple directions, and data selection and averaging of these measured values can be performed. By performing the process, it is hard to be affected by the variation of the reflected light due to the unevenness of the surface state of the measurement object, and the measurement can be performed with high accuracy. Furthermore, by arranging the slit holes of the transmission screen pattern on the circumference of concentric circles having different diameters, it is possible to select the resolution and measurement range by measuring the reflected light passing through the slit holes having different distances in the radial direction. it can. That is, the height can be measured simultaneously with various measurement ranges and resolutions.

[0007]

【Example】

(Embodiment 1) A first embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a light source for generating a minute light beam. Reference numeral 2 denotes an optical system for irradiating the measurement object 3 with the small beam light. Reference numeral 4 denotes a half mirror for deflecting the reflected light in the direction of the lens system 6 for condensing the reflected light from the measurement target 3 in the vertical direction. Reference numeral 5 denotes a transmissive screen pattern placed immediately before the lens system 6, in which a plurality of slit holes L are formed on a circumference centered on the optical axis of the reflected light. Reference numeral 7 denotes a photoelectric converter that passes through each slit hole L of the transmissive screen pattern 5 and is positioned on the optical path of each light flux condensed by the lens system 6 in a direction perpendicular to the light path, and generates an electrical output corresponding to the light receiving position of the light flux. Element. The photoelectric conversion element 7 is a one-dimensional position detection element having a certain length and having a plurality of output terminals that relatively change in output according to the irradiation position of the beam spot. It is also possible to substitute such as.

The operation of the non-contact height measuring device configured as described above will be described. First, the reflected light in the vertical direction of the minute beam light, which is spot-irradiated on the measurement target 3 by the light source 1 and the optical system 2, is guided to the transmission screen pattern 5 by the half mirror 4, and the transmission screen pattern 5 converts the reflected light into four light beams. It can be converted into split pattern light. The pattern light that has passed through each slit hole L of the transmission screen pattern 5 is condensed by the lens system 6 and irradiates the photoelectric conversion element 7 placed on the optical path of each pattern light. Generates an output corresponding to the light receiving position. That is, as shown in FIG. 2, when the height of the measuring object 3 changes to A, B, and C,
The light receiving position of the reflected light of each photoelectric conversion element 7 changes to a, b, and c, causing a difference in the output of the photoelectric conversion element 7 and calibrating the object height and the output value of the photoelectric conversion element, which have been checked in advance. The height of the measuring object 3 can be known from the curve.

At this time, a plurality of slits L are provided on the same circumference in the transmission screen pattern 5, and the reflected light transmitted through each slit is detected by the photoelectric conversion element 7 from multiple directions. By performing processing such as data selection and averaging on the output value of each photoelectric conversion element, it is less likely to be affected by variations in reflected light due to unevenness of the surface to be measured, and measurement can be performed with high accuracy.

FIG. 3A shows another example of the transmission screen pattern 5, in which a plurality of slit holes L1 and L2 are provided on concentric circles having different radii. By arranging the photoelectric conversion elements 7 corresponding to the respective slit holes L as shown in FIG. 3B, the reflected light passing through the slit hole L2 on the concentric circle having a small radius has a small resolution and a large measurement range. The reflected light that has passed through the slit hole L1 on a concentric circle with a large radius has a large resolution and a small measurement range. By selecting one of the slit holes L1 and L2 during measurement, measurement can be performed with different resolutions and measurement ranges. Becomes

(Embodiment 2) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. In FIG. 4 showing the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted, and different portions will be described. The difference from the configuration of the first embodiment is that the reflection plate 8 is arranged between the lens system 6 and the photoelectric conversion element 7 so as to be parallel to the optical axis of the lens system 6 and the arrangement direction of the photoelectric conversion element 7 And the light receiving direction of the photoelectric conversion element 7 is arranged in the x-axis direction parallel to the optical axis of the lens system 6 and along the x-axis direction. The distance between the photoelectric conversion element 7 and the optical axis of the lens system 6 is set to be twice the distance between the reflection plate 8 and the optical axis so that the photoelectric conversion element 7 can easily detect the light receiving position in the x-axis direction. Has been placed.

The operation of the non-contact height measuring device configured as described above will be described. First, the measurement object 3
The light source 1 and the optical system 2 irradiate a spot beam with a small beam, and the half mirror 4 deflects the reflected light in the vertical direction from the spot position toward the transmission screen pattern 5.
Then, the light beam after passing through the slit hole L is condensed by the lens system 6 and deflected by the reflection plate 8, and then received by the photoelectric conversion element 7 to detect the light receiving position in the x-axis direction.

As described above, the light beams passing through the slit holes L of the transmission screen pattern 5 are reflected in the directions away from each other by the reflection plate 8, and are arranged in the x-axis direction according to the change in the height of the measurement object 3. By detecting the light receiving position of the photoelectric conversion element 7 in the x direction, the photoelectric conversion element 7 can always receive a light flux close to the focal point of the reflected light. For this reason, the height of the measuring object can be measured with higher accuracy.

Embodiment 3 Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. FIG. 5 is an explanatory view of the third embodiment of the present invention. The same components as those of the second embodiment are denoted by the same reference numerals, and the description thereof will be omitted. The different portions will be described. The difference from the configuration of the second embodiment is that
This means that the photoelectric conversion elements 7 are arranged at an angle at which the gain is maximized.

The operation of the non-contact height measuring device configured as described above will be described. First, the measurement object 3
The light source 1 and the optical system 2 irradiate a spot beam with a small beam, and the half mirror 4 deflects the reflected light in the vertical direction from the spot position toward the transmission screen pattern 5.
The light is condensed by the lens system 6, deflected by the reflection plate 8, and received by the photoelectric conversion element 7. In this way, by arranging the photoelectric conversion element at an angle at which the gain is maximized, even if the reflectance of the measurement target is low, the measurement can be performed without causing a light quantity shortage, and the measurement accuracy is high. It is not affected by the reflectance. It goes without saying that the reflector 8 may be arranged at an angle at which the gain of the photoelectric conversion element 7 is maximized.

[0017]

As described above, according to the non-contact height measuring apparatus of the present invention, it is not necessary to use a special light receiving element for detecting the position of the center of gravity of the light quantity distribution, and it is possible to detect the light receiving position in the one-dimensional direction. Since measurement can be performed with a simple photoelectric conversion element, the cost can be reduced. In addition, by using a transmission screen pattern in which a plurality of slit holes are formed on the circumference, it is possible to perform measurement by a photoelectric conversion element from multiple directions, and the influence of unevenness in the reflection of the surface due to uneven surface conditions of the measurement object. Hard to receive. Therefore, it is not necessary to repeat the inspection from various directions, and the measurement can be performed at high speed and with high accuracy. Furthermore, by measuring the reflected light passing through the slit holes with different radii of the transmission screen pattern, the resolution and measurement range can be selected with a simple configuration, and it is also possible to measure at different resolutions and measurement ranges at the same time. It is.

Further, the light beam after passing through the lens system is reflected, and the light receiving angle of the photoelectric conversion element is made parallel or perpendicular to the optical axis of the lens system to make the measurement more accurate. be able to.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a non-contact height measuring device according to a first embodiment of the present invention.

FIG. 2 is a side view of the apparatus.

FIG. 3A is a front view of another transmission screen pattern used in the apparatus. FIG. 3B is a layout view of photoelectric conversion elements corresponding to the transmission screen pattern.

FIG. 4 is a side view of a non-contact height measuring device according to a second embodiment of the present invention.

FIG. 5 is a side view of a non-contact height measuring device according to a third embodiment of the present invention.

FIG. 6 is a configuration diagram of a conventional non-contact height measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Optical system 3 Object to be measured 4 Half mirror 5 Transmission screen pattern 6 Lens system 7 Photoelectric conversion element 8 Reflector

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomohiro Kimura 2-10-10 Kotobukicho, Takamatsu City, Kagawa Prefecture Inside Matsushita Hisashi Electronics Co., Ltd. (56) References JP-A-63-153419 (JP, A) JP-A-63-316432 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 11/00-11/30 102 G01C 3/00-3/32

Claims (4)

(57) [Claims] A light source for generating a minute beam light; an optical system for spot-irradiating the object to be measured with the minute beam light; an optical axis of the reflected light reflected by the object to be measured; A screen in which a plurality of slit lights are formed on the circumference around the center, and a lens system for converging the luminous flux of each reflected light passing through each slit hole of the screen on the optical axis of the reflected light. , Arranged corresponding to each light beam passing through the lens system
And outputs an electrical output corresponding to the position where the light beam is received.
A plurality of one-dimensional position detecting elements that are generated, and perform a predetermined operation from the output of the one-dimensional position detecting element.
A non-contact height measuring device for calculating the height of the object to be measured. 2. A non-contact height measuring apparatus according to claim 1, further comprising a screen having slit holes formed on the circumference of a plurality of concentric circles having different radii about the optical axis of the reflected light. . 3. A luminous flux of each reflected light passing through the lens system is reflected by a reflector disposed in parallel with the optical axis of the lens system, and the photoelectric conversion elements are respectively moved along the optical axis. The non-contact height measuring device according to claim 1, wherein the non-contact height measuring device is arranged parallel to the optical axis. 4. A light beam of each reflected light that has passed through the lens system is reflected by a reflector disposed between the lens system and the photoelectric conversion element, and the photoelectric conversion element receives each light beam vertically. 2. The non-contact height measuring device according to claim 1, wherein the height is measured.