JPH0533008U - Non-contact measuring device - Google Patents

Abstract

(57) [Summary] [Problem] To provide a non-contact type measuring device capable of accurately measuring the thickness of a light-transmissive material without being limited by its thickness. A laser light source 1, a light projecting lens 2 for projecting the laser light of the laser light source 1 onto a surface Wa of an object to be measured W, a light receiving element 4, and a light receiving element for allowing reflected light from the object to be measured W to enter the light receiving element 4. In a non-contact type measuring device including the lens 3 and measuring the thickness of the object to be measured W based on the signal from the light receiving element 4, a mask 11 is provided on the optical axis of the reflected light from the object to be measured W, Only the back surface reflected light Lb from the surface Wb opposite to the measurement surface Wa of the object to be measured is cut, and only the front surface reflected light La is received by the light receiving element 4.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a non-contact measuring device. In particular, the present invention relates to a non-contact type measuring device capable of accurately measuring the thickness of a member made of a translucent material such as glass, such as a lens.

[0002]

[Background technology]

 For example, the laser displacement meter shown in FIG. 4 is widely used for non-contact measurement of the thickness and warpage of an object to be measured. This includes a laser light source 1, a light projecting lens 2, a light receiving lens 3 and a light receiving element 4, and projects the laser light emitted from the laser light emitting source 1 through the light projecting lens 2 onto the surface Wa of the object to be measured W. Light is emitted, the reflected light from the object to be measured W is imaged by the light receiving lens 3 and is received by the light receiving element 4, and the thickness or warpage of the object to be measured W is obtained based on the signal from the light receiving element 4. Is.

[0003]

[Problems to be solved by the device]

 However, when it is attempted to measure the thickness or warpage of the measured object W made of a translucent material such as glass with a conventional laser displacement meter, as the measurement range becomes wider, the measured value from the back surface Wb of the measured object W increases. There is a problem that the backside reflected light Lb is easily affected and accurate measurement cannot be performed.

That is, as shown in FIG. 4, when laser light L is projected onto the surface Wa of the object to be measured W, the laser light L is divided into surface reflected light La (solid line) and refracted light Lb (broken line). . The refracted light Lb is reflected by the back surface Wb of the measured object W and then travels in parallel with the surface reflected light La from the front surface Wa of the measured object W. Here, when the measurement range of the laser displacement meter is wide, the back surface reflected light Lb is received by the light receiving element 4 via the light receiving lens 3, and as a result, the back surface reflected light Lb from the back surface Wb of the object W is affected. There is a problem that accurate measurement cannot be performed.

Therefore, from the above, when it is attempted to measure the thickness or warpage of the object W made of a translucent material by the conventional laser displacement meter, the thickness of the object W is measured within the measurement range. Since it is limited to about 3 times or more of the above, there is no choice but to change to a laser displacement meter having a narrow measurement range in order to measure the object W having a smaller thickness. However, this impairs versatility.

Here, the object of the present invention is to solve such a conventional problem, and to measure an object to be measured, which is made of a translucent material, without being limited in thickness. It is intended to provide a non-contact type measuring device capable of accurately measuring the thickness of an object.

[0007]

[Means for Solving the Problems]

 Therefore, the non-contact measuring device of the present invention includes a light source, a light projecting lens for projecting light from the light source onto the measurement surface of the object to be measured, a light receiving element, and a light receiving element for reflecting light from the object to be measured. In a non-contact type measuring device that includes a light-receiving lens that makes light incident on the object, and measures the thickness of the object to be measured based on the signal from the light-receiving element, the object to be measured is on the optical axis of the reflected light from the object to be measured. It is characterized in that a light shielding means for cutting off only the reflected light from the side opposite to the measurement surface is provided.

[0008]

[Action]

 When the light from the light source is projected onto the surface of the object to be measured made of a translucent material, the laser light is divided into surface reflected light and refracted light. The refracted light travels in parallel with the surface reflected light from the front surface of the DUT after being reflected on the back surface of the DUT, but is shielded by the light shielding means provided on the optical axis of the reflected light from the DUT. Since the light is cut, only the surface reflected light from the surface of the DUT is received by the light receiving element. Therefore, even for an object to be measured made of a translucent material, it is possible to accurately measure the thickness of the object to be measured without being limited in thickness.

[0009]

【Example】

 Hereinafter, preferred embodiments of the non-contact measuring device according to the present invention will be described in detail with reference to the accompanying drawings. In the following description of FIGS. 1 to 3, the same components as those in FIG. 4 described above will be denoted by the same reference numerals, and the description thereof will be omitted or simplified.

FIG. 1 shows the measurement principle of the non-contact type measuring apparatus of this embodiment. In the non-contact type measuring apparatus of the present embodiment, on the optical axis of the surface reflected light La from the object to be measured W, the surface opposite to the surface Wa which is the measurement surface of the object to be measured W 1, that is, from the back surface Wb side A mask 11 is provided as a light shielding means for cutting off only the back surface reflected light Lb. Specifically, on the optical axis of the surface-reflected light La from the object to be measured W, a mask 11 is provided between the object to be measured W and the light receiving lens 3.

As shown in FIG. 2, the mask 11 has a light receiving port 14 of a case 13 in which the above-mentioned optical elements, that is, the laser light source 11, the light projecting lens 2, the light receiving lens 3, the light receiving element 4 and the like are housed inside. The diaphragm 12 is detachably attached to the side, and has a diaphragm 12 at the center for passing only the surface reflected light La from the object to be measured W. If the diameter of the diaphragm 12 is adjustable, the versatility can be improved.

With such a configuration, when the laser light L emitted from the laser light source 1 is projected onto the front surface Wa of the object to be measured W through the projection lens 2, the laser light L is emitted from the front surface Wa. Is divided into surface reflected light La and refracted light Lb. The refracted light Lb is reflected by the back surface Wb of the object to be measured W and then travels in parallel with the surface reflected light La from the front surface Wa of the object to be measured W, but on the optical axis of the reflected light from the object to be measured W. Since it is cut by the mask 11 provided on the light receiving element 4, only the surface reflected light La from the surface Wa of the object to be measured W is received by the light receiving element 4, and the thickness of the object to be measured W is obtained based on the signal. .

Therefore, according to the present embodiment, on the optical axis of the surface reflected light La from the object to be measured W, the surface opposite to the front surface Wa which is the measurement surface of the object to be measured W, that is, from the back surface Wb side Since the mask 11 that cuts only the back surface reflected light Lb is provided, the back surface reflected light Lb from the back surface Wb of the object W can be cut. Therefore, since only the surface-reflected light La of the object to be measured W can be received by the light receiving element 4, even the object to be measured W made of a light-transmissive material is not limited in its thickness. It is possible to accurately measure the thickness of the object to be measured W and the like.

Therefore, even if the object W to be measured has a small thickness, it is not necessary to change to a laser displacement meter having a different measurement range as in the conventional case, and therefore the versatility is high and the mask 11 is simple and inexpensive. Since it can be configured, it can be made simple and inexpensive as a whole. If the diameter of the diaphragm 12 of the mask 11 can be adjusted, the versatility can be improved.

Although the present invention has been described with reference to the preferred embodiment, the present invention is not limited to this embodiment, and various improvements and design changes can be made without departing from the scope of the present invention. Of course, it is possible.

For example, in the above embodiment, the mask 11 is provided between the object to be measured W and the light receiving lens 3 on the optical axis of the surface reflected light La from the object to be measured W. As shown in FIG. 3, a mask 11 may be provided between the light receiving lens 3 and the light receiving element 4 on the optical axis of the surface reflected light La from the measured object W. However, the above embodiment has an advantage that only the mask 11 can be detachably attached to the case 13.

[0017]

[Effect of the device]

 As described above, according to the present invention, it is possible to accurately measure the thickness and the like of these measured objects even if the measured objects are made of a translucent material, without being limited in thickness.

[Brief description of drawings]

FIG. 1 is a diagram showing a measurement principle of an embodiment of the present invention.

2 is a front view showing the device of FIG. 1. FIG.

FIG. 3 is a diagram showing the measurement principle of another embodiment of the present invention.

FIG. 4 is a diagram showing a measurement principle of a conventional laser displacement meter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 laser light source 2 light projecting lens 3 light receiving lens 4 light receiving element 4 11 mask (light blocking means) W object to be measured Wa front surface Wb back surface L laser light La front surface reflected light Lb back surface reflected light

Claims (1)

[Scope of utility model registration request] 1. A light source, a light projecting lens for projecting light from the light source onto a measurement surface of an object to be measured, a light receiving element, and a light receiving lens for causing reflected light from the object to be measured to enter the light receiving element, In a non-contact type measuring device that measures the thickness of the object to be measured based on the signal from the light receiving element, from the side opposite to the measurement surface of the object to be measured on the optical axis of the reflected light from the object to be measured. A non-contact type measuring device, characterized in that it is provided with a light-shielding means for cutting off only the reflected light.