JPS62237697A - Light source - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a light source device for a latent image forming means such as a liquid crystal light shutter that forms an electrostatic latent image on an irradiating object, and more specifically, to a light source device for maintaining a constant light intensity of the light source. The present invention relates to a sight control device for controlling a scene to be controlled.

[Traditional technique]

In recent years, as a cold light source without heat dissipation, a light diffusing section is formed along the longitudinal direction on the circumferential surface of a transparent rond for light transmission, and the light incident on one end surface of the rond is diffusely reflected by the light diffusing section. Therefore, it has been proposed to emit light from the opposite direction of the light diffusing section. Since such a lighting device does not dissipate heat, it can be suitably used as a light source for a liquid crystal light shutter whose operating characteristics change depending on temperature.

By the way, when a liquid crystal optical shutter is used in a recording device,
Since the latent image potential changes when the amount of light changes, the light source is required to have a constant amount of light. Therefore,
When the above-mentioned lighting device is used as a light source, there is no heat dissipation, but the amount of light needs to be controlled to be constant. When controlling the amount of light, the amount of light emitted from the light source is detected, and the amount of light emitted from the light source is controlled based on this detected value.

Therefore, as a device for detecting the amount of light of a lighting device using the above-mentioned rondo, for example, the following device can be considered.

(1) As shown in FIG. 7, the optical sensor 23 is placed below the rod 21 at a position where it does not block the effective irradiation area A of the liquid crystal optical shutter 22. In this case, the optical sensor 23 is arranged to one side of the effective irradiation area A of the liquid crystal optical shutter 23.

(2) As shown in FIG. 8, the optical sensor 23 is placed below the end of the rod 21. Since the optical sensor 23 is located below the end of the rod 21, it does not block the light from the effective irradiation area of the liquid crystal light shutter.

(3) As shown in FIG. 9, the mirror 24 is rearranged to a position where it does not block the effective irradiation area of the liquid crystal light shutter, and the optical sensor 23 receives the light reflected from the mirror 24.

[Problems with conventional technology]

However, in the apparatus shown in FIGS. 7 and 8 described above, there is no problem as long as there is a sufficient distance between the rod 21 and the liquid crystal light shutter 22, which is the object to be irradiated, but due to the structure, the distance between the two is narrow. In this case, the effective irradiation area A of the liquid crystal light shutter 22 may be blocked by the optical sensor 23. Therefore, when attaching the optical sensor 23, high positional accuracy is required. Note that the mirror 2 shown in FIG.
4 may block light from the effective irradiation area A of the liquid crystal light shutter 22, so high positional accuracy of the mirror 24 is required.

Furthermore, if the distance between the rod 21 and the liquid crystal light shutter 22 is short, the mounting position of the optical sensor 23 will be restricted, which will affect the optical structure of the light source device and hinder the degree of freedom in design. . Further, the amount of light received by the optical sensor 23 changes depending on its angle, and the amount of light received changes depending on a slight change in the mounting position. Therefore, in the case shown in FIGS. 7 to 9 described above, changes in the amount of light received due to errors in the mounting position and angle of the optical sensor 23 must be corrected by adjusting the gain of the amplifier that amplifies the output of the optical sensor 23.

Furthermore, since the light emitted from the rod 21 is several thousand to tens of thousands of lux, all of the light shown in FIGS.
The light is attenuated by the slit 25a of the i25 and irradiated onto the optical sensor 23. However, since the amount of light received by the optical sensor 23 changes due to a slight error in the slit 25a, it is necessary to adjust the gain of the amplifier as described above, and the adjustment range is 2.
~10 times more was required.

[Purpose of the invention]

The present invention overcomes the above problems, dramatically increases the degree of freedom in the design of the device, requires relatively low precision in the mounting position of the optical sensor, and eliminates the need for light attenuation by slits. The purpose of the present invention is to provide a light source device that can perform

[Key points of the invention]

In order to achieve the above object, the present invention includes an optical transmission body and a light diffusing section formed along the longitudinal direction on the circumferential surface of the optical transmission body, and the present invention includes a light diffusion section formed on a circumferential surface of the optical transmission body, and the light is incident from one end surface of the optical transmission body. In the light source device, the light source device diffusely reflects the light from the light source by the light diffusing section and emits the light in a circumferential direction of the light transmitting body, in which a light diffusing section is formed that causes the light transmitting body to emit light for light amount detection. The present invention is also characterized in that it includes a sensor that receives the light emitted by the light diffusion section, and a control section that controls the amount of light from the light source to a predetermined amount based on the output of the sensor.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of a light source device of the present invention. In this embodiment, a light source device for a liquid crystal optical shutter will be described as an example.

In FIG. 1, reference numeral 1 denotes an optical transmission body having a circular cross section, and is made of quartz glass, silicone resin, or the like. Light from a light source such as a halogen lamp (not shown), which will be described later, is incident from one end surface of the optical transmission body 1 via an optical fiber or the like.

The light transmission body 1 functions to transmit the incident light to the other end in the axial direction. Due to this function, the optical transmission body 1
In order to reduce transmission loss, it is desirable to have high transparency and high light resistance. As shown in FIG. 2, on the outer circumferential surface of the light transmitting body 1, a light spreading section 2 is formed along the longitudinal direction to diffusely reflect the light incident from the light source. As the light diffusing part 2, transparent fine powder having a refractive index higher than that of the light transmitting body 1 is used. For example, barium sulfate, magnesia or titania are preferably used.

The light incident on the optical transmission body 1 undergoes repeated total reflection at the boundary surface and is then transmitted to the other end, and during the transmission, it is diffusely reflected into the optical transmission body 1 by the light diffusion section 2. This reflected light is directionally emitted in the opposite direction of the light diffusing section 2 by the lens action of the light transmitting body 1. The light transmitting body 1 is provided approximately at the center of the print head and extending over the entire length of the liquid crystal light shutter 3, and the light emitted from the light transmitting body 1 is projected onto the liquid crystal light shutter 3. In addition, a light diffusing section 4 for detecting the amount of light is formed on the side of one end of the optical transmission body 1 (see Fig. 2), and the incident light is emitted in the opposite direction to the light diffusing section 4 as described above. It is supposed to be done. The light diffusing section 4 for detecting the amount of light is located outside the effective irradiation area so as not to block the light projected onto the liquid crystal light shutter 3. The light diffused and reflected by the light diffusing section 4 is received by the optical sensor 6 on the driving section 5 disposed on the side of the optical transmission body 1 . The output of the optical sensor 6 is sent to the control section 8 through the flexible connector 7, and the control section 8 controls the amount of light emitted from the optical transmission body 1 to a predetermined amount by controlling the amount of light from the light source as described later. maintain. Note that the light diffusing section 4 for detecting the amount of light may be formed on the side of the center of the optical transmission body 1, as shown in FIG. In this case as well, since the light diffusion section 4 is formed on the side of the light transmission body 1, it does not interfere with the irradiation of the effective irradiation area of the liquid crystal light shutter 3.

The driving section 5 drives the liquid crystal optical shutter, and is arranged on both sides of the optical transmission body 1, and the optical sensor 6 is mounted on one side as described above. That is, as shown in FIG.
A plurality of driving LSIs 10 are mounted on a printed circuit board 9, and an optical sensor 6 is mounted on an end of the printed circuit board 9. The position of the optical sensor 6 is a position facing the light diffusion section 4 formed on the optical transmission body 1. Further, the driving LSI 10 selectively opens and closes each micro-shutter of the liquid crystal light shank 3 according to print data, so that the light emitted from the optical transmission body 1 is selectively transmitted by the micro-shutter.

This transmitted light is imaged by a lens on a photosensitive drum (not shown), and an electrostatic latent image is formed on the drum. Although a photodiode is used as the optical sensor 6 in this embodiment, a photoelectric conversion element such as a phototransistor can also be used. Further, the optical sensor 6 is mounted on the printed circuit board 9 of the drive section 5 by soldering, as shown in FIG. 5(a). This mounting method is common, but as shown in FIG. 5fb), the chip 6a of the optical sensor 6 may be directly attached to the printed circuit board 9, and its surface may be coated with resin or the like. Furthermore, the driving LSI I0 may also be mounted directly on the printed circuit board 9 as a bare chip.

This implementation includes COB, COF, as shown in the table below.
There are implementation methods such as

In the case of COF mounting, it is possible to eliminate the need for the aforementioned flexible connector (see Figure 1), and in this case,
The drive section 5 and the control section 8 can be configured integrally. Further, as described above, when the chip 6a of the optical sensor 6 is directly mounted on the printed circuit board 9, the peripheral circuits of the optical sensor 6 can also be chip-mounted on the same substrate. In this case, noise resistance can be improved.

FIG. 6 shows a specific example of a control circuit that controls light emitted from the optical transmission body 1. In FIG.

Reference numeral 11 in the figure is a current/voltage converter, which converts the output of the optical sensor 6 into a voltage. The photocurrent of the optical sensor 6 changes depending on the amount of light received, and therefore the current/TL pressure converter 11
The output voltage changes depending on the amount of light received by the optical sensor 6.

The output of the current/voltage converter 11 is sent to a differential amplifier Q2, and this amplifier Q2 has resistors R3 and R6 connected to its non-inverting terminal.
, R7, and is compared and amplified. The output of the differential amplifier Q2 is current amplified by the transistor Q3, and the output is input to the transistor Q4.

When the amount of light incident on the optical sensor 6 is small, the transistor Q4
The collector current increases, and the power supplied to the light source 12 increases. Moreover, when the amount of light incident on the optical sensor 6 increases, the collector current of the transistor Q4 decreases, and the light source 12
The power supplied to the system also decreases. In this way, the power supplied to the light source 12 is maintained at the value set by the resistors R5-R6,
Therefore, the amount of light from the light transmission body 1 that emits the light from the light source 12 is also maintained at a predetermined value. In addition, 13 in the figure is a switch for blinking the light source 12.

〔Effect of the invention〕

As explained above, according to the present invention, a light diffusing section for detecting the amount of light is formed in the light transmitting body, and this reflected light is received by the optical sensor, so that the optical path from the light transmitting body to the irradiated object is There is no need to arrange an optical sensor inside, and the conventional problem of having to attach an optical sensor with high precision can be solved. In addition, since the light is reflected to the optical sensor by the light diffusing part, it is only necessary to place the optical sensor opposite to the formation position of the light diffusing part, which dramatically increases the degree of freedom in design. This is effective when installing sensors. Furthermore, by changing the size, film thickness, material, etc. of the light diffusing section, the light meter that diffusely reflects the light can be adjusted, so that light attenuation by slits can be made unnecessary. Therefore,
Since there are no slits, there is no need to make corrections due to errors in the size of the slits, which is advantageous in terms of manufacturing.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an embodiment of the present invention, Fig. 2 is a perspective view showing the main parts of the invention, Fig. 3 is a perspective view showing another example, and Fig. 4 is a drive unit. 5(a) is a sectional view showing the mounting state of the optical sensor; FIG. 5(bl) is a sectional view showing another mounting example of the optical sensor; FIG. 6 is the above Light amount control circuit diagram of the embodiment, Figs. 7 and 8
9 and 9 are configuration diagrams showing conventional light amount detection devices, respectively. ■...Light transmission body, 2...Light diffusion section, 3...Liquid crystal light shutter, 4...Light diffusion section (for light amount detection) 5...Drive section, 6...Photo sensor, 11... Current/voltage converter, 12... Light source. Patent applicant Casio Computer Co., Ltd. Same as above
Casio Electronics Co., Ltd. No. 11'ltt No. 2 Figure 3 Figure 4 (a) (b) Factor 5 j Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] It has a light transmitting body and a light diffusing part formed along the longitudinal direction on the circumferential surface of the light transmitting body, and the light diffusing part diffuses light from a light source incident from one end surface of the light transmitting body. A light source device that reflects and emits light in a circumferential direction of the light transmission body,
A light diffusing section for emitting light for light amount detection is formed on the light transmitting body, and a sensor is provided for receiving the light emitted by the light diffusing section, and the light amount of the light source is determined based on the output of the sensor. A light source device characterized by being provided with a control section that performs quantitative control.