JPH02308665A - Picture reader - Google Patents

Abstract

PURPOSE:To save space and to reduce power consumption by using a light source radiating an original to be read in the case of reading a picture in common to a light source used for back light of a display device. CONSTITUTION:Part of light radiating from a fluorescent light 1 enters from the side face of a diffusion unit A located on the rear side of a liquid crystal panel 2. A unit A realizes a role of diffusing light on the entire panel and a role of lighting each small area uniformly. On the other hand, a read original O is carried between a roller 3 and a glass plate 4 with the carrier roller 3. The fluorescent light 1 lights the part of the original O to be read through the glass plate 4 and its reflecting light forms an image of the part of the original to be read to a photodetector section of a photodetector array 6 with a short focus array lens 5. Thus, the light source for radiating the original O and the light source used for a back light of the panel 2 are used in common.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a device for reading images of manuscripts, etc.

E. Prior Art] Computers, word processors, etc. are usually used by being connected to display devices, printers, and image input devices. In order to realize space saving and power saving of the entire system, a liquid crystal panel has been used as a display device. A liquid crystal panel has liquid crystal sealed between two glass plates with transparent electrodes attached, and uses electrical signals to change the alignment direction of the liquid crystal molecules and control the amount of light transmitted. In order to improve the quality of the display, many use the so-called backlight method, which illuminates from the back of the liquid crystal panel. Regarding image reading apparatuses, there have been so-called sheet-through type image reading apparatuses in which reading is performed by transporting the original to be read while the reading position remains stationary.

[Problems] However, it has been difficult to achieve significant space and power savings because the light source for the backlight of the display device and the light source for irradiating the document to be read of the image reading device are major constraints.

Means for Solving Problem E] In order to solve this problem, the present invention uses a light source that irradiates the original to be read 1^ when reading an image in common with a light source used for the backlight of the display device. Adopt means.

[First Embodiment] FIG. 1 is a diagram illustrating the configuration of a first embodiment of the present invention. FIG. 2 is a diagram of the same embodiment viewed from the longitudinal direction of the conveyance roller. FIG. 3 is an enlarged view of a portion of the diffusion unit into which light is incident.

A part of the light emitted from the fluorescent lamp enters from the side of the diffusion unit A located on the back side of the liquid crystal panel 2 and travels through the acrylic plate 10. A light scattering pattern II is printed on the two acrylic plates 10 by screen printing. The combination of two patterns achieves the role of generally dispersing light to the entire panel and the role of uniformly illuminating each small area. In the figure, 13 is a diffusion plate, 12 is a reflection plate, and the side ends are fixed with light-shielding tape 14.

Next, the reading operation will be explained. The part to be read M0 is conveyed between the conveyance roller 3 and the glass 4 by the conveyance roller 3. The fluorescent lamp 1 illuminates the area to be read of the document on the glass 4, and the reflected light is converted into COD by the short focus array lens array 5.
An image of the portion to be read of the document is formed on the light receiving portion of the light receiving element array 6 such as the above. 13 indicates a light shielding plate.

The charges accumulated in the light receiving element row in proportion to the amount of light received by each light receiving element are shifted by a shift pulse to an analog shift register with the same number of light receiving elements, and transferred by a transfer pulse.
Sequentially extracted as image signals! Line image data is retrieved. The above process of extracting one line of image data is repeated in synchronization with the conveyance operation by the stepping motor, and the document is read.

[Second Embodiment] FIG. 4 is a diagram illustrating the configuration of a second embodiment of the present invention.

Two cold cathode tubes 7 and 8 provide backlight for the liquid crystal display.

The light emitted from the two cold cathode tubes 7 and 8 to the side opposite to the liquid crystal display device t is incident on the wavelength conversion condensing film 9. This wavelength conversion film 9 is a film that confines a fluorescent substance, and utilizes the fact that the fluorescence emitted by absorbing incident light is totally reflected on the film surface. In other words, the fluorescence generated within the film is dispersed in all directions, but most of it is totally reflected and reaches the sides of the film. Furthermore, three of the side surfaces of the film are mirrored so that light is emitted only in the direction where the image reading mechanism is located. In this way, the light emitted from the two cold cathode tubes to the side opposite to the 1IIIi crystal display device is focused onto the read portion of the image reading device through the wavelength conversion light focusing film.

Since the reading operation section is the same as that in the first embodiment, the explanation thereof will be omitted.

Of course, the present invention is not concerned with the type of light source, backlight, or image reading method. The display device is not limited to one connected to a computer or a word processor. It is also conceivable to provide a backlight using a plurality of light sources, some of which may be used as light sources for image reading.

[Effects of the Invention] By using the light source that illuminates the original to be read when reading an image as the light source used for the backlight of the display device, it is possible to save space and power.

[Brief explanation of drawings]

FIG. 1 is a perspective view illustrating the configuration of an embodiment of the present invention. FIG. 2 is a sectional view of the embodiment viewed from the longitudinal direction of the conveying roller. Figure 3 shows the same university JJi! FIG. 2 is an enlarged view of a portion into which light is incident in one example of a diffusion unit. FIG. 4 is a sectional view illustrating the configuration of a second embodiment of the present invention. In the figure, 1 is a fluorescent lamp, 3 is a transport roller, 6 is a light receiving element array serving as a reading means, and 7 is a cold shade 8i screen.

Claims (1)

[Scope of Claims] A display device having a backlight, comprising means for guiding and irradiating the light from the light source that provides the backlight onto the original to be read, and forming an image of the original by reflecting light from the original onto a light receiving unit. An image reading device having an image sensor that reads.