JPH04318438A - Lens-meter - Google Patents

Abstract

PURPOSE:To measure the refracting power of a lens to be inspected even when the lens has a very powerful prism. CONSTITUTION:When a lens G to be inspected is brought into contact with a contact member 3 and a light source is turned on after fixing a variable-angle mirror 5 so that the optical path 01 of the luminous flux made incident to the mirror 5 and the optical path 02 of the reflected luminous flux from the mirror 5 can intersect at right angles at the time of measuring the refracting power of the lens G to be inspected, the luminous flux from a light source 1 is made incident to the lens G after the luminous flux is transformed to a parallel flux by means of a lens 2. The luminous flux passed through the lens G is reflected by the mirror 5 and forms four transmitted luminous flux images on the image pickup element 7 of a TV camera and the refracting power is calculated from the positional relation among the images. When the lens G is the powerful prism and the transmitted luminous flux images are formed on the outside of the element 7, the mirror 5 is tilted and the refracting power is found by taking the titled angle of the mirror 5 into account.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens meter used, for example, in ophthalmology clinics, optician shops, and the like.

0002

[Prior Art] In conventional general lens meters, a light beam is incident on a lens to be tested, is refracted, and the transmitted light beam is received on a photoelectric sensor, and the refractive power of the lens to be tested is measured from the shift in the light receiving position. are doing.

0003

However, the above-mentioned conventional example has the disadvantage that if the prism degree of the lens to be tested is too large, the transmitted light beam will deviate from the photoelectric sensor and cannot be received, making measurement impossible.

SUMMARY OF THE INVENTION An object of the present invention is to provide a lens meter that can measure the refractive power even of a lens to be tested with a large degree of prism.

[0005]

[Means for Solving the Problems] The present invention for achieving the above object projects a projected light beam from a light source onto a test lens, receives the transmitted light flux on a photoelectric sensor, and measures the refractive power of the test lens. In a lens meter that performs and calculation means for determining the refractive power of the lens to be tested from.

The present invention related to the above-mentioned specific invention provides a lens meter that projects a projected light flux from a light source onto a test lens, and measures the refractive power of the test lens by receiving the transmitted light flux on a photoelectric sensor. It has a switching means for switching the incident angle of the projection light beam incident on the test lens, and a calculation means for calculating the refractive degree of the test lens from the incident angle of the projection light flux and the position of the transmitted light flux on the photoelectric sensor. It is characterized by this.

[0007]

[Operation] When the lens to be tested has a large degree of prism, the lens meter having the above configuration changes the projection angle of the transmitted light beam that has passed through the lens to be tested and projects it onto the photoelectric sensor using a variable angle optical member. Perform refractive power measurement. Alternatively, the incident angle of the projection light beam used for measuring the lens to be tested is changed, the light beam is made incident on the lens to be tested, and the transmitted light beam is received on the photoelectric sensor to measure the refractive power.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail based on the illustrated embodiments. FIG. 1 is a configuration diagram of the first embodiment. On the optical path O1 of the light source 1, there are a lens 2, a contact member 3 for contacting the test lens G, and four apertures as shown in FIG. 4a-4d
A four-hole diaphragm 4 having a diaphragm 4 and a variable angle mirror 5 that can be rotated as shown by an arrow by a driving means (not shown) are provided. An image sensor 7 of a television camera 6 is placed on the optical path O2 in the reflection direction of the variable angle mirror 5, and the output of the image sensor 7 is connected to a television monitor 8. Note that the focal position of the lens 2 coincides with the position of the light source 1.

When measuring refractive power, the lens G to be tested is brought into contact with the contact member 3, and the optical path O of the light beam incident on the variable angle mirror 5 is adjusted.
The variable angle mirror 5 is fixed and the light source 1 is turned on so that the optical path O2 of the reflected light beam is orthogonal to the optical path O2 of the reflected light beam. The light beam from the light source 1 travels on the optical path O1, is made into a parallel light beam by the lens 2, and then enters the lens G to be tested. Then, the transmitted light beam is reflected by the variable angle mirror 5, and as shown in FIG.
The transmitted light flux images Ma to Md are formed on the image sensor 7 of the television camera 6, and their positions are displayed on the television monitor 8. When the test lens G does not have prism power, these transmitted light flux images Ma to Md are symmetrical with respect to the optical axis, and the distance between the transmitted light flux images Ma and Mc and the distance between Md and Mb can be calculated from the distance between the transmitted light flux images Ma and Mc, and the distance between Md and Mb. The refractive power in each radial direction is calculated by the means.

When the lens G to be tested has a degree of prism, the positions of the centers of gravity of these transmitted light flux images Ma to Md are shifted from the measurement optical axis, so that the degree of prism can be calculated from the shift of the center of gravity. However, if the degree of prism is too large, it becomes impossible to receive all of the transmitted light flux images Ma to Md on the image sensor 7, as shown in FIG. 4, for example. In this case, the examiner may tilt the variable angle mirror 5 in which direction while observing the television monitor 8 or automatically determining where the beam images Ma to Md remain within the angle of view. The inclination angle of the variable angle mirror 5 is changed so that the total transmitted light flux images Ma to Md can be received. From the center of gravity of images Ma to Md, test lens G
Calculate the prism degree of. Note that the transmitted light flux image received before the angle of the variable angle mirror 5 is changed can be easily identified from the positional relationship of the transmitted light flux images Ma to Md. In addition, a one-dimensional CCD is orthogonally arranged in place of the image sensor 7,
A display pattern of the position of the transmitted light flux image may be displayed on the television monitor 8. It is preferable to provide a switch for detecting the movement of the variable angle mirror 5 in order to store the positions of the transmitted light flux images Ma to Md before and after the tilting of the variable angle mirror 5 starts and ends.

FIG. 5 shows a configuration diagram of the second embodiment, and FIG.
The same reference numerals indicate the same members. In this embodiment, instead of the light source 1 and the lens 2, a light source 1' and a lens 2' that can be moved while being arranged around the optical path O1 are provided, and the variable angle mirror 5 of the first embodiment is provided. is omitted. If the prismatic degree of the test lens G is large,
By moving the light source 1' and lens 2' themselves, the optical axis O is shown by the dotted line.
If placed above the light source 1', it becomes possible to receive the totally transmitted light beam images Ma to Md on the image sensor 7, so that the same effect as the variable angle mirror 5 can be obtained, and the position of the light source 1', that is, the subject The degree of refraction can be determined from the angle of incidence of the projected light flux onto the lens G and the positions of the transmitted light flux images Ma to Md on the image sensor 7.

FIG. 6 shows a configuration diagram of a third embodiment, in which instead of the light source 1' movable around the optical path O1, a 90° angle is placed on and around the optical path O1 as shown in FIG. For example, five light sources 9a to 9e are arranged at symmetrical positions.

When the prism degree of the lens G to be tested is small, the light flux passing position from the central light source 9a is as shown in FIG. 8(a).
As shown in FIG. 9(a), four transmitted light beam images Ma to Md are received on the image sensor 7 as shown in FIG. 9(a), making it possible to measure refractive power. If the prism degree is too large, the light flux passing position from the light source 9a will be as shown in FIG. 8(b), so the transmitted light flux image on the image sensor 7 will be as shown in FIG.
As shown in (b), measurement becomes impossible. In this case, when the light source 9a is turned off and the light source 9d is turned on, the light flux passing position becomes as shown in FIG. 8(c).
As shown in FIG. 9(c), since the total transmitted light flux images Ma to Md can be received on the image sensor 7, measurement can be performed from the position of the light source 9d and the position of the transmitted light flux images Ma to Md.

FIG. 10 shows a configuration diagram of the fourth embodiment. On the optical path O1 of the light source 1, as shown in FIG. An image sensor 12 consisting of a contact member 3, a lens 11, and four photosensors 12a to 12d as shown in FIG. It is considered to be approximately conjugate.

When there is no test lens G and the center aperture 10a of the liquid crystal diaphragm 10 is opened, the luminous flux image P of the light source 1 is focused at the center of the image sensor 12 as shown in FIG. 13(a). If the lens G to be tested does not have prismatic power, the refractive index is calculated from the size of the beam image. When the lens G to be tested includes a prism degree, the light flux image P' is, for example, as shown in FIG.
(b) Since it shifts to the dotted line position, the photosensor 12a
The prism degree is calculated from the received light amount ratio of ~12d. Also,
If the degree of prism is large and the luminous flux image P deviates from the image sensor 12 as shown in FIG. In this embodiment, the same effect as when another light source is turned on can be obtained. Note that the measurement limit is the position of the luminous flux image P'' shown by the dotted line.

[0016]

[Effects of the Invention] As explained above, the lens meter according to the present invention changes the projection angle of the transmitted light beam onto the photoelectric sensor using the angle-variable reflecting member when the prism degree of the lens to be tested is excessively large. Alternatively, since the incident angle of the projected light beam on the test lens is changed and the light is guided onto the photoelectric sensor to measure the refractive power, it is possible to measure the refractive power of the test lens with a large degree of prism.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a front view of a four-hole diaphragm.

FIG. 3 is an explanatory diagram of the position of a transmitted light beam image on an image sensor.

FIG. 4 is an explanatory diagram of the position of a transmitted light beam image on an image sensor when the degree of prism is large.

FIG. 5 is a configuration diagram of a second embodiment.

FIG. 6 is a configuration diagram of a third embodiment.

FIG. 7 is an explanatory diagram of the arrangement positions of light sources.

FIG. 8 is an explanatory diagram of the light flux passing position of the light source.

FIG. 9 is an explanatory diagram of the position of a transmitted light beam image on an image sensor.

FIG. 10 is a configuration diagram of a fourth embodiment.

FIG. 11 is a front view of a liquid crystal aperture.

FIG. 12 is a front view of the image sensor.

FIG. 13 is an explanatory diagram of the position of a transmitted light beam image on an image sensor.

[Explanation of symbols]

1, 1' light source 3 Contact member 4 4-hole aperture 5　Angle variable mirror 6 TV camera 7, 12 Imaging device 8 TV monitor 10 Liquid crystal aperture

Claims (2)

[Claims] 1. A lens meter that measures the refractive power of the test lens by projecting a projected light flux from a light source onto a test lens and receiving the transmitted light flux on a photoelectric sensor, wherein the test lens measurement light flux is adjusted to an angle. a light-receiving optical system that projects onto the photoelectric sensor via a variable reflection member; and a calculation means for determining the refractive power of the test lens from the inclination angle of the angle-variable reflection member and the position of the transmitted light beam on the photoelectric sensor. A lens meter comprising: 2. A lens meter that measures the refractive power of the test lens by projecting a projected light flux from a light source onto the test lens and receiving the transmitted light flux on a photoelectric sensor, in which the refractive power of the test lens is measured. A lens meter comprising: a switching means for switching the incident angle of the projection light beam; and a calculation means for determining the refractive power of the test lens from the incidence angle of the projection light beam and the position of the transmitted light beam on the photoelectric sensor.