JP3477921B2 - Projector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projector capable of measuring the length of each part of an object placed on a stage.

[0002]

2. Description of the Related Art Conventionally, as this type of projector, there is known a projector provided with a stage on which an object to be inspected is mounted and a projection lens for projecting the object to be inspected on a screen. When measuring the length of the measurement part (measurement side length, distance between two measurement points, etc.) of the test object with this projector, a scale is applied to the projected image of the test object formed on the screen. , And read the length of the measurement part of the projected image on a scale. In this case, the value obtained by dividing the value read on the scale with the magnification of the projection lens is the length of the measurement portion of the test object.

Further, as a conventional projector, an XY stage movable in the X-axis and Y-axis directions orthogonal to each other, a screen having a cross-shaped line composed of two reference lines orthogonal to each other, and an object to be inspected It is known that a projection lens for projecting on a screen and an X-axis and Y-axis movement amount detecting means for detecting the movement amounts of the XY stage in the X-axis and Y-axis directions are known. The measurement of the length of the test object by this projector is performed by the following procedure. (1) In order to make the measuring direction of the object to be measured (the direction of the measuring side or the direction of the straight line connecting the two measuring points) completely parallel to the moving direction of the XY stage (X-axis direction or Y-axis direction), Move the inspected object on the XY stage while looking at the screen so that the measurement part of the projected image (measurement side, two measurement points, etc.) is completely parallel to one of the reference lines of the crosshair. Adjust. (2) The XY stage is moved so that one end of the projection image measurement unit is aligned with the other reference line of the crosshair. The position of the XY stage at that time is read by the detecting means. The value at this time is referred to as "read value A". (3) The XY stage is moved so that the other end of the measurement unit for the projected image is aligned with the other reference line of the crosshair. The position of the XY stage at that time is read by the detecting means. The value at this time is referred to as "read value B". (4) Find the difference between the "read value A" and the "read value B". The difference is the length of the measurement part of the test object.

[0004]

However, in the former prior art described above, since a scale is applied to the projected image on the screen and the length of the measuring portion of the projected image is read by the scale, the projection of the entire object is projected. The image must fit within the projection plane of the screen. Therefore, there is a problem in that the magnification of the projection lens that can be used is limited, and highly accurate length measurement cannot be performed.

Further, in the latter prior art, in order to make the measuring direction of the object to be measured completely parallel to the moving direction of the XY stage, the measuring portion of the projected image is completely parallel to one of the reference lines of the crosshair. X while looking at the screen so that
It has to be moved on the Y stage, which requires skill and time.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a projector capable of highly accurately measuring a length and capable of easily performing a measuring operation in a short time. .

[0007]

In order to solve the above-mentioned problems, a projector according to a first aspect of the present invention provides a stage on which an object to be inspected is placed and an object to be inspected on the stage at a predetermined position. And a rotary screen having a reference mark consisting of at least one straight line or two points, which is arranged at the predetermined position and onto which the projection image of the test object is projected, and a rotation angle of the screen. Rotation angle detecting means for detecting, X-axis and Y of the stage and the projection optical system
In a projector equipped with X-axis and Y-axis movement amount detecting means for detecting relative movement amounts in the axial direction, the reference mark and a straight line connecting two measurement points of the projected image have a predetermined relationship. The rotation angle obtained when the screen is rotated, and the projection image is moved by a distance between the measurement points in the direction of a straight line connecting the two measurement points on the rotated screen. The X axis and Y obtained when the stage or the projection optical system is moved.
A calculation means for calculating the length between the two measurement points of the test object is provided based on the amount of movement in the axial direction.

The projector according to a second aspect of the invention is provided with display means for displaying the length calculated by the calculation means.

[0009]

In the projector according to the first aspect, the rotation angle obtained when the screen is rotated so that the reference mark of the rotating screen and the straight line connecting the two measurement points of the projected image have a predetermined relationship with each other. , Its X-axis and Y-axis directions obtained when the stage or the projection optical system is moved so that the projected image moves in the direction of the straight line connecting the two measurement points on the rotated screen by the distance between the measurement points The calculation means calculates the length between the two measurement points of the test object on the basis of the moving amount. Therefore, when measuring the length of the test object, the screen may be rotated so that the reference mark of the rotating screen and the straight line connecting the two measurement points of the projected image have a predetermined relationship. Does not need to be moved on the XY stage to adjust its position. Moreover, since it is not necessary for the projected image of the entire test object to fit within the screen, there is no restriction on the projection magnification of the test object.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a contour projector according to an embodiment of the present invention. This contour projector has X
The XY stage 1 movable in the axial and Y-axis directions, the rotating screen 2, and the test object 3 placed on the XY stage 1.
And a projection optical system 5 for forming a projected image 4 by projecting the image on the projection surface of the rotating screen 2. Projection head 5a
Is composed of a rotating screen 2 and a projection optical system 5.

An XY stage (hereinafter simply referred to as a stage) 1 has an X-axis handle 6 for moving the stage 1 in the X-axis direction and a Y-axis handle for moving the stage 1 in the Y-axis direction. 7 and a vertical movement handle 8 for moving the stage 1 up and down for focusing. Further, on the stage 1, an X-axis encoder 9 which reads a movement amount in the X-axis direction and outputs an encoder signal indicating the movement amount, and a movement amount in the Y-axis direction, and outputs an encoder signal indicating the movement amount. Y-axis encoder 10 is provided.

On a projection surface of a rotary screen (hereinafter, simply referred to as a screen) 2, a cross line 11 is formed by two reference lines 11x and 11y which are orthogonal to each other.
The intersection of the reference lines 11x and 11y coincides with the rotation center of the screen 2. When the screen 2 is at the reference position shown in FIG. 2 (when the rotation angle θ of the screen 2 is 0 °), the reference line 11x coincides with the X-axis moving direction of the stage 1 and the reference line 11y is the Y-axis of the stage 1. It is configured to match the moving direction. Also, on the screen 2,
An encoder 12 is provided which reads the rotation amount and outputs an encoder signal representing the rotation amount (see FIG. 3).

FIG. 1 shows a signal processing circuit of the contour projector. This signal processing circuit receives the encoder signal output from the encoder 12, receives the encoder signal output from the counter 21 that counts the rotation amount of the screen 2, and the encoder signal output from the X-axis encoder 9, and moves the stage 1 in the X-axis direction. The stage 1 receives the encoder signal output from the Y-axis encoder 10 and the counter 22 that counts the amount.
And a counter 23 for counting the amount of movement in the Y-axis direction.

The output signals of the counters 21, 22 and 23 are input to the angle calculator 24, the X-axis movement amount calculator 25, and the Y-axis movement amount calculator 26, respectively. Angle calculator 2
4 calculates the rotation angle θ from the reference position from the value counted by the counter 21. X-axis movement amount calculation unit 2
5 is the stage 1 from the value counted by the counter 22.
The amount Xm of movement of X in the X-axis direction is calculated. The Y-axis movement amount calculation unit 26 calculates the movement amount Ym of the stage 1 in the Y-axis direction from the value counted by the counter 23.

The output signals of the calculation units 24, 25 and 26 are input to the X'-axis coordinate conversion unit 27 and the Y'-axis coordinate conversion unit 28, respectively.

The X'-axis coordinate conversion unit 27 includes an angle calculation unit 24.
The rotation angle θ calculated in step 2, the X-axis movement amount Xm calculated by the X-axis movement amount calculation unit 25, and the Y-axis movement amount calculation unit 2
Using the amount of movement Ym in the Y-axis direction calculated in step 6, the amount of movement in the X-axis direction Xm in the X′Y ′ coordinate system rotated by the rotation angle θ with respect to the XY coordinate system of the stage 1. It is configured to convert to Xw. The calculation formula is shown by the following formula.

Xw = XmCOSθ + YmSINθ (1) The Y′-axis coordinate conversion unit 28 uses the rotation angle θ, the movement amount Xm in the X-axis direction, and the movement amount Ym in the Y-axis direction to calculate the movement amount in the Y-axis direction. Ym is converted into a movement amount Yw in the X'Y 'coordinate system. The calculation formula is shown by the following formula.

Yw = YmCOSθ−XmSINθ (2) Further, in the signal processing circuit of FIG.
And an X'-axis coordinate display section 30 and a Y'-axis coordinate display section 31 (see FIG. 2). Rotation angle display section 29
Displays the rotation angle θ calculated by the angle calculation unit 24. The X′-axis coordinate display unit 30 displays the movement amount Xw calculated by the X′-axis coordinate conversion unit 27 as the length on the X′-axis. The Y′-axis coordinate display unit 31 includes the Y′-axis coordinate conversion unit 2
The moving amount Yw calculated in 8 is displayed as the length on the Y'axis.

Next, a procedure for measuring the length of the object 3 to be measured by the contour projector according to the above embodiment will be described. Here, as one measurement example, a case will be described in which the length of one side (measurement side) 3a of the rectangular test object 3 is measured. (1) Place the test object 3 on the stage 3 at an arbitrary angular position. As a result, the projection image 4 of the object 3 is projected onto the projection optical system 5.
Is formed on the projection surface of the screen 2 (see FIG. 2). (2) The reference line 11x of the crosshair 11 is the measurement side 4 of the projected image 4.
The screen 2 is rotated from the reference position shown in FIG. 2 so as to be parallel to a. FIG. 3 shows a state in which the screen 2 is rotated from the reference position by an angle θ so that the reference line 11x is parallel to the measurement side 4a. When the screen 2 is rotated from the reference position, the rotation amount is read by the encoder 12, and the rotation amount is counted by the counter 21. The angle calculation unit 24 calculates the rotation angle θ from the reference position from the value counted by the counter 21, and the rotation angle θ is displayed on the rotation angle display unit 29. (3) With the reference line 11x and the measurement side 4a parallel to each other, the handles 6 and 7 are operated to move the stage 1 to the X-axis and Y-axis.
By moving in the axial direction, one end (point A) of the measurement side 4a of the projected image 4 is aligned with the reference line 11y (see FIG. 4).
At this time, the counters 22 and 23 are reset and the count value of each is set to zero. (4) Next, operate the handles 6 and 7 to move the stage 1 to the X position.
The other end (point B) of the measurement side 4a is aligned with the reference line 11y by moving in the axis and Y-axis directions (see FIG. 5).

Thus, the point A on the measurement side 4a is the reference line 1
From the position corresponding to 1y (the position in FIG. 4) to B on the measurement side 4a
When the stage 1 is moved to a position where the points coincide with the reference line 11y (position in FIG. 5), the X-axis movement amount Xm of the stage 1 is read by the X-axis encoder 9 and the Y-axis movement amount thereof is read. Ym is read by the Y-axis encoder 10. FIG. 6 shows a movement coordinate diagram when the stage 1 is moved from point A to point B.

The encoder signal from the X-axis encoder 9 is counted by the counter 22, and the X-axis movement amount Xm is calculated by the X-axis movement amount calculation unit 25 from the counted value. On the other hand, the encoder signal from the Y-axis encoder 10 is counted by the counter 23, and the movement amount Ym in the Y-axis direction is calculated by the Y-axis movement amount calculation unit 26 from the counted value.

The X'-axis coordinate conversion unit 27 includes an angle calculation unit 2
4, the rotation angle θ output from the X-axis movement amount calculation unit 25 and the Y-axis movement amount calculation unit 26, and the movement amounts Xm and Y in the X-axis direction.
The amount of movement Ym in the axial direction is used to perform the calculation of the above equation (1) to convert the amount of movement Xw in the X′Y ′ coordinate system (see FIG. 6).

On the other hand, the Y'-axis coordinate conversion unit 28 performs the calculation of the above equation (2) by using the rotation angle θ, the movement amount Xm in the X-axis direction and the movement amount Ym in the Y-axis direction, and thereby the Y-axis is calculated. The movement amount Ym in the direction is converted into the movement amount Yw in the X'Y 'coordinate system.

The movement amount Xw calculated by the X'-axis coordinate conversion unit 27 is displayed as the length on the X'-axis on the X'-axis coordinate display unit 30, and is calculated by the Y'-axis coordinate conversion unit 28. The moved amount Yw is displayed as the length on the Y'axis on the Y'axis coordinate display unit 31. Here, the movement amount Xw displayed on the X′-axis coordinate display unit 30 indicates the length of the measurement side 3 a of the test object 3.

In this way, the length of the measuring side 3a of the test object 3 is measured.

The other side 3b of the object 3 (see FIG. 2)
The reference line 11y of the crosshair 11 when measuring the length of
The screen 2 is rotated from the reference position so that is parallel to the measurement side 4b of the projected image 4. By moving the stage 1 in the X-axis and Y-axis directions in this state, one end (point A) of the measurement side 4b of the projected image 4 is aligned with the reference line 11x. At this time, the counters 22 and 23 are reset and the count value of each is set to zero. Next, by moving the stage 1 in the X-axis and Y-axis directions, the other end (point C) of the measurement side 4b of the projected image 4 is aligned with the reference line 11x. When such a measurement is performed, the movement amount Yw displayed on the Y′-axis coordinate display unit 31 indicates the length of the measurement side 3b of the test object 3.

Also, regarding the distance between two measurement points of the test object, for example, the distance between the centers of the two holes formed in the test object, the length of the measurement side of the test object 3 is measured. The measurement can be performed in the same manner as in the case of That is, assuming that the center points of the two holes are points A and B, the screen 2 is rotated so that one of the reference lines 11x and 11y is parallel to an imaginary straight line connecting the points A and B, and thereafter, Object 3 mentioned above
This is the same as the case of measuring the length of the measurement side 3a.

As described above, according to the above-described embodiment, the length of the test object 3 (the length of the measurement side, the distance between two measurement points, etc.)
When measuring, the screen 2 may be rotated so that the crosshairs 11 of the rotating screen 2 and the measurement side of the projected image 4 or an imaginary straight line connecting two measurement points are parallel to each other. Does not need to be moved on the XY stage 1 to adjust its position. Moreover, since it is not necessary for the projected image of the entire test object 3 to fit within the rotary screen 2, there is no restriction on the magnification of the projection optical system 5 that projects the test object 3 onto the rotary screen 2. Therefore, highly accurate length measurement can be performed, and the measurement work can be easily performed in a short time.

In the above embodiment, the encoder 12
The counter 21, and the angle calculator 24 constitute a rotation angle detecting means for detecting the rotation angle of the rotary screen 2. X-axis encoder 9, counter 22,
The X-axis movement amount calculation unit 25 constitutes X-axis movement amount detection means for detecting the movement amount of the XY stage 1 in the X-axis direction. Then, the Y-axis encoder 10 and the counter 23
The Y-axis movement amount calculation unit 26 constitutes Y-axis movement amount detection means for detecting the movement amount of the XY stage 1 in the Y-axis direction.

In the above embodiment, the rotary screen 2 is used.
However, the present invention is not limited to this. That is, even when the rotary screen 2 is provided with a reference mark composed of at least one straight line or two points instead of the cross hair 11, the same effect as that of the above-described embodiment can be obtained.

In the above embodiment, the reference lines 11x,
Although the rotary screen 2 is rotated so that one of 11y and the measurement side of the projected image 4 or an imaginary straight line connecting two measurement points are parallel to each other, the present invention is not limited to this. For example, one of the reference lines 11x and 11y and a measurement side of the projected image 4 or an imaginary straight line connecting two measurement points form an arbitrary angle (for example, a right angle) (in a predetermined relationship), The rotary screen 2 may be rotated.
In this case, the length Xw or Yw, which is the measurement result, may be corrected by the arbitrary angle.

Although the stage is moved and the focus is adjusted by the handle in the above embodiment, these operations may be performed electrically or by CNC control.

Further, the projection lens 5 and the projection head 5a may be moved at the same time for focusing.

Further, focusing may be performed using an infinity projection lens.

A photoelectric microlaser may be used to detect the amount of movement in the X-axis direction and the Y-axis direction.

The projection head 5a may be moved instead of the stage.

[0038]

As described above, according to the projector of the first aspect of the invention, the reference mark of the rotating screen and the straight line connecting the two measurement points of the projected image have a predetermined relationship. Move the stage or the projection optical system so that the rotation angle obtained when the screen is rotated and the projected image moves by the distance between the measurement points in the direction of the straight line connecting the two measurement points on the rotated screen. Based on the movement amounts in the X-axis and Y-axis directions obtained when the calculation is performed, the calculation means calculates the length between the two measurement points of the test object. Therefore, when measuring the length of the test object, the screen may be rotated so that the reference mark of the rotating screen and the straight line connecting the two measurement points of the projected image have a predetermined relationship. Does not need to be moved on the XY stage to adjust its position. Moreover, since it is not necessary for the projected image of the entire test object to fit within the screen, there is no restriction on the projection magnification of the test object. Therefore, highly accurate length measurement can be performed, and the measurement work can be easily performed in a short time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a signal processing circuit of a projector according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a projector according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a state in which a rotary screen is rotated.

FIG. 4 is an explanatory diagram showing a measurement procedure.

FIG. 5 is an explanatory diagram showing a measurement procedure.

FIG. 6 is a movement coordinate diagram when the stage 1 is moved.

[Explanation of symbols]

1 XY stage 2 rotating screen 11 Crosshairs (reference mark) 12 Encoder (rotation angle detection means) 21 Counter (rotation angle detection means) 24 Angle calculation unit (rotation angle detection means) 9 X-axis encoder (X-axis movement amount detection means) 22 Counter (X-axis movement amount detection means) 25 X-axis movement amount calculation section (X-axis movement amount detection means) 10 Y-axis encoder (Y-axis movement amount detection means) 23 Counter (Y-axis movement amount detection means) 26 Y-axis movement amount calculation unit (Y-axis movement amount detection means) 27 X'axis coordinate conversion unit (calculation means) 28 Y'axis coordinate conversion unit (calculation means) 30 X'axis coordinate display section (display means) 31 Y'axis coordinate display section (display means)

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01B 9/08 G01B 11/02

Claims (2)

(57) [Claims] 1. A stage on which an object to be inspected is placed, a projection optical system for projecting the object to be inspected on the stage to a predetermined position,
A rotary screen which has at least one straight line or a reference mark consisting of two points, is arranged at the predetermined position, and onto which the projection image of the test object is projected, and a rotation angle detection means for detecting the rotation angle of the screen. And an X-axis and Y-axis movement amount detecting means for detecting relative movement amounts of the stage and the projection optical system in the X-axis and Y-axis directions, respectively. The rotation angle obtained when the screen is rotated so that the straight line connecting the two measurement points has a predetermined relationship, and the projection image is a straight line connecting the two measurement points on the rotated screen. Based on the amount of movement in the X-axis and Y-axis directions that is obtained when the stage or the projection optical system is moved so as to move in the direction of the distance between the measurement points. A projector having a calculation means for calculating the length between the two measurement points. 2. The projector according to claim 1, further comprising display means for displaying the length calculated by the calculation means.