JPH0726842U - Brightness control of light source - Google Patents

Abstract

(57) [Summary] [Object] To provide a projector capable of adjusting the illuminance by appropriately changing the value of the current flowing through the light source lamp according to the distance between the projector and the screen and the zooming magnification. [Structure] A first sensor for detecting a lens position for focus adjustment and a lens position information signal from the first sensor
First A / D- / D-converted and output as upper address signal
A D converter, a second sensor for detecting the zoom lens position, and a second signal for A / D converting the information signal of the zoom lens position from the second sensor and outputting it as a lower address signal.
An A / D converter, a memory for outputting data according to the values of the upper address signal and the lower address signal, and a control unit for adjusting the light amount adjusting unit according to the data from the memory and changing the light amount of the light source lamp. It consists of.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a projector device.

[0002]

[Prior art]

 Conventionally, an image output device such as a liquid crystal projector is fixed to a common lens provided on a fixed body fixed to the body of the optical device and a first movable body movable along the optical axis with respect to this fixed body. The focusing lens is interposed between the fixed body and the first moving body to move the first moving body with respect to the fixed body, and the first moving body is rotated by the rotation of the focusing motor. Focus adjustment is performed by having a first operation ring, rotating the operation ring by a predetermined angle, and moving the focus adjustment lens of the first moving body. Furthermore, in the case of changing the projection magnification by zooming (zooming), a second operating ring provided inside the first moving body and rotated by the rotation of the zooming motor is used. In addition, the projection magnification is varied by rotating the second operation ring by a predetermined angle and moving the variable power lens fixed to the second moving body. The standard value of the brightness of the light source of the projector configured as described above is, for example, when the distance between the projector and the screen is 10 meters at the maximum and the zooming magnification is 5 times at the maximum. Since it is a necessary condition that the degree is 100 (lux) or more, the maximum rated value of the current flowing through the light source lamp is determined to satisfy the illuminance. However, for example, when the distance between the projector and the screen becomes 5 meters, or when the zooming magnification is doubled, the illuminance on the screen increases according to each distance and magnification. However, the current that flows in the light source lamp remains unchanged, which causes the screen to become too bright, consumes unnecessary power, and shortens the life of the light source lamp. Had.

[0003]

[Problems to be solved by the device]

 In view of the above problems, the present invention provides a projector capable of adjusting the illuminance by appropriately changing the value of the current flowing through the light source lamp according to the distance between the projector and the screen or the zooming magnification. To provide.

[0004]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a first sensor for detecting a lens position for focus adjustment and a first sensor for detecting a lens position for focus adjustment, and an information signal of the lens position from the first sensor. A / D converter that performs A / D conversion and outputs as a higher-order address signal, a second sensor that detects the zoom lens position, and an information signal of the zoom lens position from this second sensor that is A / D converted A second A / D converter that outputs as a lower address signal, a memory that inputs the upper address signal and the lower address signal, and outputs the stored data according to the address value, and the output data of this memory The reading unit includes a control unit that adjusts the light amount adjusting unit according to the read value, and a light source lamp that changes the light amount by the light amount adjusting unit.

[0005]

[Action]

 With the above configuration, in the liquid crystal projector according to the present invention, a predetermined address value is input to the memory via the sensor according to the rotation of the motor that adjusts the positions of the focus adjustment lens and the variable power lens. Therefore, the control unit reads the data corresponding to this address value, adjusts the light amount adjustment unit according to the read value, and this light amount adjustment unit adjusts the current flowing to the light source lamp to adjust the light amount. Can be changed.

[0006]

【Example】

 Hereinafter, an embodiment of a liquid crystal projector according to the present invention will be described in detail with reference to the drawings. In the embodiment of FIG. 1, reference numeral 21 is a first sensor for focus adjustment. An information signal of the lens position from the first sensor is input to an A / D converter 22 and the A / D converted value is stored in a memory. It outputs to the upper address terminal 26 of 23. On the other hand, a second zoom sensor 24 inputs the information signal of the zoom lens position from the second sensor to the A / D converter 25, and the converted value is inputted to the lower address terminal 27 of the memory 3. Output to. The control unit 28 reads the data corresponding to the address values of the upper address terminal 26 and the lower address terminal 27 of the memory 23, inputs the read value to the D / A converter 29, and the D / A converted value. Is input to the light quantity adjusting unit 30 to control the current flowing through the light source lamp 31.

Next, the optical system for the focus adjustment and zooming operations will be described with reference to FIG. In the figure, the movable frames 2 and 9 respectively hold a lens 1 constituting a focusing lens system and a zoom adjusting lens 8 at their inner diameters. By moving the lens 14 fixed inside the lens 14 relatively in the optical axis direction, continuous focusing and zooming, that is, zooming is performed. The lens 1 in front of the lens systems 1 and 2 for focusing is temporarily held by the holding moving frame 2, and then the holding moving frame 2 is movable via the helicoid screw portion 4 of the holding fixed frame 3. It has become. When the distance ring 5 is rotated around the optical axis, the protrusion 6 fitted in the spirally formed screw groove of the helicoid screw portion 4 moves back and forth together with the motor support 7 along the screw portion 4. Moreover, since the motor support 7 is fixed to the holding and moving frame 2, the lens 1 constituting the focusing can also be moved back and forth along the optical axis for focusing. On the other hand, the front lens 8 of the lenses 8 and 2 constituting the variable power lens system is once held by the holding frame 9, and then the holding frame 9 is attached to the holding moving frame 2 via the helicoid screw portion 10. It is screwed and integrally formed with the indirect moving frame 12. Further, a zoom ring 13 is formed on the outer peripheral portion of the indirect moving frame 12, and when the zoom ring 13 is rotated around the optical axis, the holding frame 9 is also rotated and the holding movement is performed. The projection 11 of the frame 2 and the helicoid colloid 10 allow the lens holding frame 9 to move forward and backward relative to the moving frame 2 in the optical axis direction, and the lens 2 adjusts the magnification. That is, the lens 14 serves both as a distance adjusting lens and a variable power lens.

The fixed terminal of the sliding resistor 16 is connected to the rotating shaft of the motor 17, and rotates as the motor rotates. The resistance film of the sliding resistor 17 presses the resistance surface as the motor rotates, whereby the movable contact of the sliding resistor 17 rotates on the resistance film by a predetermined angle. The other terminal of the sliding resistor 17 is connected to one terminal of the resistive film, rotates together with the sliding resistor 17, and a constant current is applied to the sliding resistor. The voltage level between the terminals of the sliding resistor 17 changes due to this constant current, this voltage level is A / D converted by the A / D converter, and this A / D converted value is set to the upper address of the memory. input. The fixed terminal of the sliding resistor 18 is connected to the rotating shaft of the motor 19 and rotates with the rotation of the motor, and the resistance film of the sliding resistor 18 has a resistance surface as the motor rotates. , Which causes the movable contact of the slide resistor 18 to rotate on the resistance film by a predetermined angle. The other terminal of the sliding resistor 18 is connected to one terminal of the resistance film, rotates together with the sliding resistor 18, and a constant current is applied to the sliding resistor. The voltage level between the terminals of the sliding resistor 18 due to the constant current changes, this voltage level is A / D converted by the A / D converter, and this A / D converted value is input to the lower address of the memory. To do. In this way, the specified address value is input to the memory according to the rotation of the motor that adjusts the positions of the focus adjustment lens and the variable power lens, and the control unit responds to this address value. The light intensity of the light source lamp can be adjusted by reading the data. Regarding the contents of the address value and the data value of the memory, the upper address value when the distance between the screen and the projector is closest is # 80, the value when the distance is farthest is # 00, and the middle thereof is # 40. , The lower address value when the zoom magnification is the smallest is # 08, the largest is # 00 and the middle is # 04. For example, when the distance between the screen and the projector is the closest, Further, the address value of the memory is # 88 when the zoom magnification is the smallest, and the memory value at this time is set to # 100. By storing the data in this way, even if the combination of the distance between the screen and the projector and the zoom magnification becomes various values, the address value is input to the memory and the desired value is read by reading the data. The current value data can be obtained.

[0009]

[Effect of device]

 As described above, according to the brightness control of the light source according to the present invention, it is possible to know the information about the projection distance and the screen size by detecting the position of the lens. By referring to the correspondence table with the amount of power supplied to the light source, the required amount of power is supplied to the light source, which makes the brightness on the screen constant regardless of the distance between the lens and the screen and the magnification. In addition, since the light source is not always used with full specifications, the life of the light source lamp can be extended.

[0010]

[Effect of device] [Brief description of drawings]

FIG. 1 is a block diagram of a liquid crystal projector according to the present invention.

FIG. 2 is a diagram illustrating the operation of the liquid crystal projector according to the present invention.

[Explanation of symbols]

 1 sensor 2 A / D converter 3 memory 4 address terminal 5 sensor 6 A / D converter 7 address terminal 8 controller 9 D / A converter 10 light intensity adjuster 11 light source lamp

Claims (1)

[Scope of utility model registration request] 1. A first sensor for detecting a lens position for focus adjustment, and a first A / D converter for A / D converting an information signal of the lens position from the first sensor and outputting as an upper address signal. , Second to detect zoom lens position
A sensor, a second A / D converter for A / D converting the information signal of the zoom lens position from the second sensor and outputting it as a lower address signal, and inputting the upper address signal and the lower address signal and inputting the address A brightness control of a light source, comprising: a memory that stores data according to a value; and a control unit that reads data from the memory and adjusts a light amount adjustment unit according to the read value.