JPH03223830A - Light projecting device for camera - Google Patents

Abstract

PURPOSE:To individually execute the focusing of a projection pattern and the adjustment of a light projecting direction by movably supporting an LED in the optical axis direction of a light projecting lens by a supporting member and providing a mount surface where the light projecting lens can be eccentric in a plane orthogonally crossed with the optical axis. CONSTITUTION:The supporting member 14 movably supports the LED 10 in the optical axis direction of the light projecting lens 12, and the mount surface where the lens 12 can be eccentric in the plane orthogonally crossed with the optical axis is provided. Since the adjustment of the light projecting direction is performed with the parallel eccentricity of the lens 12 and the focusing of a projection pattern image is performed with the back-and-forth movement of the LED, two kinds of adjustment are independently performed. Thus, accurate positioning is accomplished, and the increase of cost is checked because the structure of the device is simple.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention particularly relates to a light projection device for a camera used for focus detection.

[Prior Art] Conventionally, when the object strength is low and especially when the contrast is low, accurate detection becomes difficult with a passive focus detection device, so a predetermined pattern of light is projected. Until now, when assembling the components of this type of projector, the installation work had been carried out within the precision of the parts, but in order to project a pattern of a sufficient size, the light source energy had to be adjusted. There was some waste, and there were problems that would increase costs if parts were made more accurate.

On the other hand, - conventional cameras had a detection area limited to the center of the screen, but - eye reflex cameras are required to perform focus detection for subjects located in different parts of the screen. Focus detection devices equipped with a plurality of detection sensors are increasingly being incorporated into cameras.

In this case, since it is necessary that the projected pattern is received well by each detection sensor, the apparatus needs to be manufactured with higher precision than in the past.

[Problems to be Solved by the Invention] An object of the present invention is to eliminate the above-mentioned waste or to enable highly accurate adjustment.

[Means for Solving the Problems] The present invention includes an LED serving as a light source, a light projecting lens for guiding the emitted light flux of the LED to a subject, and a support member supporting the projecting lens and the LED. In the camera light projection device, the support member supports the LED movably along the optical axis of the light projection lens, and is mounted to allow the light projection lens to be decentered within a plane perpendicular to the optical axis. It is configured to have a surface so that focusing of the projection pattern and adjustment of the direction of light projection can be performed independently.

[Example 1] Figures 1 to 7 show examples according to the present invention, and Figure 1 is a cross-sectional view showing one embodiment of the present projector incorporated into a single-lens reflex camera. A camera body, 2 a lens barrel that holds an imaging lens 3 movably in its front axis direction, 4
A half mirror 6, which divides the subject light into a focus detection device 5 and a finder system, is a focusing plate, and together with a pentaprism 7 and an eyepiece 8, constitutes a finder system. Reference numeral 9 denotes a submirror for guiding the light beam transmitted through the half mirror 4 to a known focus detection device 5 which can detect a plurality of locations. 10
is an LED, which constitutes an auxiliary light projection system for focus detection together with a dome 11 that protects the light source and adjusts the directivity of the light beam, and a projection lens 12. 13 is an LED package.

The auxiliary light projection system is made into a unit by a work described below, and is incorporated into, for example, a camera body.

The LEDIO has a light emitting part shape as shown by diagonal lines in FIG. 2, and this pattern is projected onto the subject and becomes subject information for focus detection.

3 to 5 are detailed views of the auxiliary light projection unit, with FIG. 3 being a perspective view of the components, and FIG. 4 being a perspective view of the assembled state. In the figure, 14 is a support member, and the LED
O package 13 supports dome 11 and light projection lens 12. Numeral 15 is an adjustment screw used for adjusting the position of the support member 11. The dome 11 is provided with pins llc and lid on the surface in contact with the support member 14, and the support member 14
It penetrates and is supported by the positioning hole 14c and the oblique elongated hole 14d. On the other hand, for this dome, LED package 1
3 are fixed with transparent adhesive with their optical axes aligned. 14a.

14b is a flexible connecting arm that connects the front and rear parts of the support member. During assembly of the unit, the mounting surfaces of the wing portions 12e and 12f of the projecting lens 12 are pressed against the mounting surfaces of the fixing columns 14e and 14f of the support member 14 by an assembly jig so that they are flush with each other. The eccentricity of the optical axis is adjusted in the directions of arrows A and B so that the light flux emitted from the LED 10 reaches the adjustment subject within the distance measurement field of the focus detection device 5 via this projection lens. After the adjustment is completed, the fixing columns 14e, 14f and the wing parts 12e, 12
Bonding is performed using an adhesive between f. 12g, 1
2h is an adjustment hole for holding a jig used for this eccentric adjustment.

FIG. 5 is a sectional view showing a state in which the light projection unit is fixed to the substrate 16 of the camera body. The base body 16 has a fixed bottle 16j and a screw hole 1 in the slide guide part 16.
6Il is provided, and the fixing hole 14j of the support member I4
A fixed pin 16j is press-fitted into the support member 14, and a slide guide portion 16k is slidably fitted into a guide groove 14k of the support member 14. Further, the adjustment screw 15 is screwed into the base body 16 by sandwiching the bottom portion of the support member 14 . The support member 14 is provided with a slope 14i that contacts the head 15i of the adjustment screw 15, and generates a component force that moves the LED lo and the dome 11 in the direction of arrow C as the adjustment screw 15 moves forward and backward by rotation. are doing.

Focus adjustment of a projection pattern using a force applied in the direction of arrow C will be described with reference to FIGS. 6 and 7. Figures 6 and 7 are plan views of the light projecting unit viewed from above. Figure 6 shows the adjustment screw 15 in the position shown in Figure 5, and Figure 7 shows the adjustment screw 15 screwed in further. Each case is shown. Connecting arms f4a, 14b of support member 14
has flexibility, and allows the rear part of the support member that supports the LED 10 and the front part that supports the light projecting lens to be brought close to each other and separated from each other. Therefore, when the adjustment screw 15 is screwed in and a force is generated that pushes the slope 14i of the support member away, the connecting arms 14a-14b are bent and the position of the LED is moved rearward. That is, the distance between the light projection lens 12 and the LEDIO in FIG. 7 is larger than the distance between the light projection lens 12 and the LED 10 in FIG. 6. In this way, the out-of-focus of the projection pattern caused by manufacturing errors of each component can be corrected by moving the adjustment screw 15 forward and backward while monitoring the focus position.

As described above, since the direction of light projection is adjusted by the parallel eccentricity of the light projection lens 12, and the focus of the projected pattern image is adjusted by moving the LED back and forth, these two adjustments can be performed independently. Very easy to assemble.

Incidentally, the base body 16 may be a casing that is detachably attached to the camera body. Further, on the upper side, the front part of the support body is fixed to the base body, but the rear part may be fixed. The pattern may be provided on a separate negative film and illuminated.

[Effects of the Invention] According to the present invention described above, since the basic constituent elements of the unit can be adjusted independently, there is an effect that accurate positioning can be performed. In addition, since the structure for this purpose is simple, the desired purpose can be achieved without increasing costs, which is a great advantage.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example in which a light projection device according to the present invention is incorporated into a single-lens reflex camera. FIG. 2 is an explanatory diagram showing the shape of the light emitting part of the LED. 3 and 4 are perspective views of the light projecting device. FIG. 5 is a sectional view of the light projecting device. FIG. 6 and FIG. 7 are top views of the light projecting device, respectively. In the figure, 10 is an LED, 12 is a light projecting lens, 14 is a support member, 14a and 14b are connecting arms, and 16 is a base. /4. 6 figure 2

Claims (1)

[Claims] (1) An LED serving as a light source, a light projection lens for guiding the emitted light flux of the LED to the subject, and the light projection lens and the LE
D, the supporting member supports the LED so as to be movable in the optical axis direction of the light projecting lens, and the light projecting lens is perpendicular to the optical axis. A camera light projection device characterized by having a mounting surface that can be decentered within a plane.